<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no,scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\nI ask this seriously and respectfully. And I apologize if it seems\nlike a troll. I always feel uncomfortable when I hear physicists make\nstatements about beauty. Who here thinks reality is ugly?\nInterestingly, I do not hear mathematicians speak like this as often\nas I do physicists. So what is it that string theorists find so\nbeautiful? Brian Greene did not convey it to me. Sorry and thanks.\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>I ask this seriously and respectfully. And I apologize if it seems
like a troll. I always feel uncomfortable when I hear physicists make
statements about beauty. Who here thinks reality is ugly?
Interestingly, I do not hear mathematicians speak like this as often
as I do physicists. So what is it that string theorists find so
beautiful? Brian Greene did not convey it to me. Sorry and thanks.
Peter Woit
Jul22-04, 10:40 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no,scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>backdoorstudent wrote:\n\n>I ask this seriously and respectfully. And I apologize if it seems\n>like a troll. I always feel uncomfortable when I hear physicists make\n>statements about beauty. Who here thinks reality is ugly?\n>Interestingly, I do not hear mathematicians speak like this as often\n>as I do physicists. So what is it that string theorists find so\n>beautiful? Brian Greene did not convey it to me. Sorry and thanks.\n\n\nI\'ve spent a lot of time thinking about this question, since the idea\nthat the universe can be described by a complicated 11 dimensional theory,\nwith 7 of them having a complicated structure which explains everything we\nsee, seems to be neither elegant nor beautiful.\n\nFor one thing, some string theorists (e.g. Susskind) are now explicitly\narguing that string theory is not an elegant theory, that its virtue is\nthat it can describe all sorts of complicated things, some of which are\ncomplicated enough to produce intelligent life. In his talks, Susskind\nexplicitly sneers at and criticizes the use of the term "elegant" to\nrefer to string theory.\n\nFirst of all, what does it mean to be "elegant"? Roughly what I\nthink this means is that a huge amoutnt of structure is packaged in\na small number of simple principles or equations. The Dirac\nequation is probably the best example: it is very simple, uses surprising\nideas from mathematics, and explains a huge range of complicated\nphenomena.\n\nWhy do string theorists call the theory elegant? The main thing to\nkeep in mind is that string theorists don\'t really know what string\ntheory is.\nAs a result, I think there are two reasons they call the theory elegant.\n\n1. What is known about string theory is that it is supposed to\nencompass a lot of different phenomena associated with 2d QFT,\nespecially conformal field theory.\n2d QFT is a fantastic subject, with a lot of examples of beauty and\nelegance. Often you can write down a very simple 2d QFT, and show\nthat it has a huge amount of very deep and surprising mathematical\nstrucure. Unfortunately these structures don\'t seem to have anything\nto do with the real world. None of the most beautiful aspects of\nCFT explain anything about the world, and if you want to make contact\nwith real physics, you need to bring in exceedingly complex and ugly\nCFTs.\n\n2. As long as you don\'t know what string theory really is, you can\nkeep hoping that it is something truly wonderful and beautiful. The\nbeautiful, elegant theory that string theorists often are referring to\nis the one they hope exists. Two of Witten\'s definitions of the "M"\nin M-theory are "Mystery" and "Magic". Much of the beauty of\nM-theory is the beauty of mystery, of something you don\'t understand\nthat you invest with your hopes and dreams. Other similar statements\nare characterizations of string theory as something magical that\ndropped in from the 21st century to the 20th, or as a spaceship we\ndon\'t have the instruction manual for. But maybe if one ever\nunderstands what M-theory is, it will turn out to be something\nhorribly complicated and ugly (see Susskind). Maybe the mysterious\nobject string theorists think is a space-ship is really a toaster.\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>backdoorstudent wrote:
>I ask this seriously and respectfully. And I apologize if it seems
>like a troll. I always feel uncomfortable when I hear physicists make
>statements about beauty. Who here thinks reality is ugly?
>Interestingly, I do not hear mathematicians speak like this as often
>as I do physicists. So what is it that string theorists find so
>beautiful? Brian Greene did not convey it to me. Sorry and thanks.
I've spent a lot of time thinking about this question, since the idea
that the universe can be described by a complicated 11 dimensional theory,
with 7 of them having a complicated structure which explains everything we
see, seems to be neither elegant nor beautiful.
For one thing, some string theorists (e.g. Susskind) are now explicitly
arguing that string theory is not an elegant theory, that its virtue is
that it can describe all sorts of complicated things, some of which are
complicated enough to produce intelligent life. In his talks, Susskind
explicitly sneers at and criticizes the use of the term "elegant" to
refer to string theory.
First of all, what does it mean to be "elegant"? Roughly what I
think this means is that a huge amoutnt of structure is packaged in
a small number of simple principles or equations. The Dirac
equation is probably the best example: it is very simple, uses surprising
ideas from mathematics, and explains a huge range of complicated
phenomena.
Why do string theorists call the theory elegant? The main thing to
keep in mind is that string theorists don't really know what string
theory is.
As a result, I think there are two reasons they call the theory elegant.
1. What is known about string theory is that it is supposed to
encompass a lot of different phenomena associated with 2d QFT,
especially conformal field theory.
2d QFT is a fantastic subject, with a lot of examples of beauty and
elegance. Often you can write down a very simple 2d QFT, and show
that it has a huge amount of very deep and surprising mathematical
strucure. Unfortunately these structures don't seem to have anything
to do with the real world. None of the most beautiful aspects of
CFT explain anything about the world, and if you want to make contact
with real physics, you need to bring in exceedingly complex and ugly
CFTs.
2. As long as you don't know what string theory really is, you can
keep hoping that it is something truly wonderful and beautiful. The
beautiful, elegant theory that string theorists often are referring to
is the one they hope exists. Two of Witten's definitions of the "M"
in M-theory are "Mystery" and "Magic". Much of the beauty of
M-theory is the beauty of mystery, of something you don't understand
that you invest with your hopes and dreams. Other similar statements
are characterizations of string theory as something magical that
dropped in from the 21st century to the 20th, or as a spaceship we
don't have the instruction manual for. But maybe if one ever
understands what M-theory is, it will turn out to be something
horribly complicated and ugly (see Susskind). Maybe the mysterious
object string theorists think is a space-ship is really a toaster.
Michael Varney
Jul22-04, 10:44 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no,scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n"backdoorstudent" <backdoorstudent@yahoo.com> wrote in message\nnews:750f5e99.0407211611.61f734a6@posting.google.com...\n>\n> I ask this seriously and respectfully. And I apologize if it seems\n> like a troll. I always feel uncomfortable when I hear physicists make\n> statements about beauty. Who here thinks reality is ugly?\n> Interestingly, I do not hear mathematicians speak like this as often\n> as I do physicists. So what is it that string theorists find so\n> beautiful? Brian Greene did not convey it to me. Sorry and thanks.\n\nBeauty is in the eye of the beholder... a truism that applies to physicists\nas well.\nReality is ugly in many cases.\n\nHowever, the mathematical description of reality is considered beautiful\nwhen it is concise, succinct, simple and encompassing.\n\nString theory is beautiful in its potential to unify physics... no\nadjustable parameters.\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>"backdoorstudent" <backdoorstudent@yahoo.com> wrote in message
news:750f5e99.0407211611.61f734a6@posting.google.com...
>
> I ask this seriously and respectfully. And I apologize if it seems
> like a troll. I always feel uncomfortable when I hear physicists make
> statements about beauty. Who here thinks reality is ugly?
> Interestingly, I do not hear mathematicians speak like this as often
> as I do physicists. So what is it that string theorists find so
> beautiful? Brian Greene did not convey it to me. Sorry and thanks.
Beauty is in the eye of the beholder... a truism that applies to physicists
as well.
Reality is ugly in many cases.
However, the mathematical description of reality is considered beautiful
when it is concise, succinct, simple and encompassing.
String theory is beautiful in its potential to unify physics... no
adjustable parameters.
FrediFizzx
Jul23-04, 06:34 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no,scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n\n"backdoorstudent" <backdoorstudent@yahoo.com> wrote in message\nnews:750f5e99.0407211611.61f734a6@posting.google.com...\n|\n| I ask this seriously and respectfully. And I apologize if it seems\n| like a troll. I always feel uncomfortable when I hear physicists make\n| statements about beauty. Who here thinks reality is ugly?\n| Interestingly, I do not hear mathematicians speak like this as often\n| as I do physicists. So what is it that string theorists find so\n| beautiful? Brian Greene did not convey it to me. Sorry and thanks.\n\nErr... It is the Universe that is elegant and beautiful; not necessarily\nstring theory. Now, I happen to believe that this is a thing of freakin\'\nbeauty; vacuum charge = +,- sqrt(hbar*c). Quite possibly the simplest\nexpression of the marriage of QM + SR = QFT. The thing that I think is\nbeautiful about string theory is the concept of one thing being able to\nmaking it all. If you have massless point-like quantum entities traveling\nat c, they are going to be like strings. So strings make sense to me. Even\nif the point-like quantum entities are strings, you have strings making\nstrings. Fantastic!\n\nFrediFizzx\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>"backdoorstudent" <backdoorstudent@yahoo.com> wrote in message
news:750f5e99.0407211611.61f734a6@posting.google.com...
|
| I ask this seriously and respectfully. And I apologize if it seems
| like a troll. I always feel uncomfortable when I hear physicists make
| statements about beauty. Who here thinks reality is ugly?
| Interestingly, I do not hear mathematicians speak like this as often
| as I do physicists. So what is it that string theorists find so
| beautiful? Brian Greene did not convey it to me. Sorry and thanks.
Err... It is the Universe that is elegant and beautiful; not necessarily
string theory. Now, I happen to believe that this is a thing of freakin'
beauty; vacuum charge = +,- \sqrt(\hbar*c). Quite possibly the simplest
expression of the marriage of QM + SR = QFT. The thing that I think is
beautiful about string theory is the concept of one thing being able to
making it all. If you have massless point-like quantum entities traveling
at c, they are going to be like strings. So strings make sense to me. Even
if the point-like quantum entities are strings, you have strings making
strings. Fantastic!
FrediFizzx
Ulmo
Jul23-04, 06:35 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no,scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\nbackdoorstudent@yahoo.com (backdoorstudent) wrote in message news:<750f5e99.0407211611.61f734a6@posting.google.com>...\n> I ask this seriously and respectfully. And I apologize if it seems\n> like a troll. I always feel uncomfortable when I hear physicists make\n> statements about beauty. Who here thinks reality is ugly?\n> Interestingly, I do not hear mathematicians speak like this as often\n> as I do physicists. So what is it that string theorists find so\n> beautiful? Brian Greene did not convey it to me. Sorry and thanks.\n\nPhysicists usually use the word "elegant" and they use it to mean\nsomething that is predicted by the theory, or falls out naturally,\ninstead of being put in my hand in an ad hoc way, such as in gauge\ntheory, in the process of making it gauge invariant, you have to add\nvector term, which can then be identified with the gauge bosons that\nmediate the force.\n\nDavid\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>backdoorstudent@yahoo.com (backdoorstudent) wrote in message news:<750f5e99.0407211611.61f734a6@posting.google.com>...
> I ask this seriously and respectfully. And I apologize if it seems
> like a troll. I always feel uncomfortable when I hear physicists make
> statements about beauty. Who here thinks reality is ugly?
> Interestingly, I do not hear mathematicians speak like this as often
> as I do physicists. So what is it that string theorists find so
> beautiful? Brian Greene did not convey it to me. Sorry and thanks.
Physicists usually use the word "elegant" and they use it to mean
something that is predicted by the theory, or falls out naturally,
instead of being put in my hand in an ad hoc way, such as in gauge
theory, in the process of making it gauge invariant, you have to add
vector term, which can then be identified with the gauge bosons that
mediate the force.
David
Doug Sweetser
Jul23-04, 08:25 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no,scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\nHello "student":\n\n> So what is it that string theorists find so beautiful? Brian Greene\n> did not convey it to me. Sorry and thanks.\n\nI bought the 3 hour Nova documentary, not the book. Beauty,\nelegance, and mystery is all part of the way string theory is marketed\nto the general public which finances string theory. To "seriously and\nrespectively" challenge the beauty and elegance could be taken as a\nchallenge to financing. One needs to be careful.\n\nFor me, it is equations where one should look for beauty. In the TV\ndocumentary, only the second hour on the history of string theory had\nequations. Because I owned the DVD, I was able to stop and take a look\nat a few.\n\nThe first was the Euler Beta function. Gabriele Venezioano in 1968 used\nit to describe the strong force. The Beta function looks with obvious\nASCII limitations like so:\n\nB(p, q) = L(p) L(q)/L(p+q)\n\nThe L\'s are suppose to be capital gammas. Gammas are a continuous form\nof factorials, something that did strike me as really cool. Beta is\nfor a function with two variables. As for what beta does, here is one\ndescription:\n\n"The beta function comes into picture when calculating the total density\nby performing convolutions of classical state densities which have a\npower law form. An example is the situation of two subsystems composed\nof different sets of harmonic oscillators s1 and s2. Then the density\nis a function of B(s1, s2)."\n\n[from http://www.2dcurves.com/gamma/gammab.html]\n\nSuskind wrote the next equation from memory on a blackboard. It was an\nexample of beta in action:\n\nA(s, t) = L(1 - alpha(s)) L(1 - alpha(t)) / L(2 - alpha(s) - alpha(t))\n\nThey did not tell what alpha(s) or alpha(t) where. One of Suskind\'s\ncontributions was that this beta function could not only be stretched\nand compressed but also could vibrate at different frequencies. This\nfunction could thus represent a string of some sort in the strong\nforce. I could understand his words, but not see the string itself, so\nthat is frustrating.\n\nThis approach to the strong force had important technical problems, with\na massless particle and anomalies. It was John Schwartz in 1973 who\nfirst suggested a connection to gravity. The equation there was quite\ncomplicated:\n\nF_grav ~ i /2 g^2 (8 pi alpha\') g^4 [(P_1 - P_2)^2 - P_1^2 P_2^2/D-2]\ndelta phi_1 phi_2 delta phi_1 phi_2\n\nAlthough the massless particle now had the role of the graviton, there\nwere still anomalies. A calculation by Green and Schwartz in Aspen\n(1984?) during a thunderstorm showed that the number of gravitational\nanomalies, 496, exactly equaled the Yang Mills Anomalies at 496. That\nmeant that the theory was consistent. The calculation shown was far\ntoo complicated for anyone but an expert to follow. Still, it was\nperhaps the most satisfying because it looked like two very complicated\ncalculations were used to test the theory, and it passed a tough test.\n\nThe only partial equation to appear on the third episode was one of\nWitten\'s from String 95 where he unified the 5 string theories:\n\nG^10 = e^-gamma\nI = 1/2 Int d^10 x g^(1/2) e^-3 gamma R ...\n\nThe partial doodle had little impact on me, although it rocked the\nmeeting. That d^10 means the theory is in ten dimensions. To be\nbeautiful requires to be seen. String theorist try to sell the idea\nthat the six or seven hidden dimensions are part of a beautiful,\nmind-expanding concept. The compactification proposal is hollow for me\nbecause I will never be able to visit. Being there is a key to the\nappreciation of beauty.\n\nAt this time I do not find string theory beautiful or elegant. The\nequations look too complicated. That may be because Nature is that\nway, but I remain skeptical (in a positive sense of the word,\nrespecting this body of work while hoping for something better). I\nsupport the continued funding because the peer review process continues\nto find there are avenues worth exploring.\n\ndoug\nquaternions.com\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Hello "student":
> So what is it that string theorists find so beautiful? Brian Greene
> did not convey it to me. Sorry and thanks.
I bought the 3 hour Nova documentary, not the book. Beauty,
elegance, and mystery is all part of the way string theory is marketed
to the general public which finances string theory. To "seriously and
respectively" challenge the beauty and elegance could be taken as a
challenge to financing. One needs to be careful.
For me, it is equations where one should look for beauty. In the TV
documentary, only the second hour on the history of string theory had
equations. Because I owned the DVD, I was able to stop and take a look
at a few.
The first was the Euler \Beta function. Gabriele Venezioano in 1968 used
it to describe the strong force. The \Beta function looks with obvious
ASCII limitations like so:
B(p, q) = L(p) L(q)/L(p+q)
The L's are suppose to be capital gammas. Gammas are a continuous form
of factorials, something that did strike me as really cool. \Beta is
for a function with two variables. As for what \beta does, here is one
description:
"The \beta function comes into picture when calculating the total density
by performing convolutions of classical state densities which have a
power law form. An example is the situation of two subsystems composed
of different sets of harmonic oscillators s1 and s2. Then the density
is a function of B(s1, s2)."
[from http://www.2dcurves.com/\gamma/gammab.html]
Suskind wrote the next equation from memory on a blackboard. It was an
example of \beta in action:
They did not tell what \alpha(s) or \alpha(t) where. One of Suskind's
contributions was that this \beta function could not only be stretched
and compressed but also could vibrate at different frequencies. This
function could thus represent a string of some sort in the strong
force. I could understand his words, but not see the string itself, so
that is frustrating.
This approach to the strong force had important technical problems, with
a massless particle and anomalies. It was John Schwartz in 1973 who
first suggested a connection to gravity. The equation there was quite
complicated:
Although the massless particle now had the role of the graviton, there
were still anomalies. A calculation by Green and Schwartz in Aspen
(1984?) during a thunderstorm showed that the number of gravitational
anomalies, 496, exactly equaled the Yang Mills Anomalies at 496. That
meant that the theory was consistent. The calculation shown was far
too complicated for anyone but an expert to follow. Still, it was
perhaps the most satisfying because it looked like two very complicated
calculations were used to test the theory, and it passed a tough test.
The only partial equation to appear on the third episode was one of
Witten's from String 95 where he unified the 5 string theories:
G^{10} = e^-\gammaI = 1/2 \Int d^{10} x g^(1/2) e^-3 \gamma R ...
The partial doodle had little impact on me, although it rocked the
meeting. That d^{10} means the theory is in ten dimensions. To be
beautiful requires to be seen. String theorist try to sell the idea
that the six or seven hidden dimensions are part of a beautiful,
mind-expanding concept. The compactification proposal is hollow for me
because I will never be able to visit. Being there is a key to the
appreciation of beauty.
At this time I do not find string theory beautiful or elegant. The
equations look too complicated. That may be because Nature is that
way, but I remain skeptical (in a positive sense of the word,
respecting this body of work while hoping for something better). I
support the continued funding because the peer review process continues
to find there are avenues worth exploring.
doug
quaternions.com
Franz Heymann
Jul25-04, 09:16 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no,scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n\n\n\n"Michael Varney" <varney@colorado_no_spam.edu> wrote in message\nnews:cmQLc.19\\$Xt6.5081@news.uswest.net...\n>\n> "backdoorstudent" <backdoorstudent@yahoo.com> wrote in message\n> news:750f5e99.0407211611.61f734a6@posting.google.com...\n> >\n> > I ask this seriously and respectfully. And I apologize if it seems\n> > like a troll. I always feel uncomfortable when I hear physicists\nmake\n> > statements about beauty. Who here thinks reality is ugly?\n> > Interestingly, I do not hear mathematicians speak like this as\noften\n> > as I do physicists. So what is it that string theorists find so\n> > beautiful? Brian Greene did not convey it to me. Sorry and thanks.\n>\n> Beauty is in the eye of the beholder... a truism that applies to\nphysicists\n> as well.\n> Reality is ugly in many cases.\n>\n> However, the mathematical description of reality is considered\nbeautiful\n> when it is concise, succinct, simple and encompassing.\n>\n> String theory is beautiful in its potential to unify physics... no\n> adjustable parameters.\n\nAnd no testable predictions?\n\nFranz\n\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>"Michael Varney" <varney@colorado_no_spam.edu> wrote in message
news:cmQLc.19$Xt6.5081@news.uswest.net...
>
> "backdoorstudent" <backdoorstudent@yahoo.com> wrote in message
> news:750f5e99.0407211611.61f734a6@posting.google.com...
> >
> > I ask this seriously and respectfully. And I apologize if it seems
> > like a troll. I always feel uncomfortable when I hear physicists
make
> > statements about beauty. Who here thinks reality is ugly?
> > Interestingly, I do not hear mathematicians speak like this as
often
> > as I do physicists. So what is it that string theorists find so
> > beautiful? Brian Greene did not convey it to me. Sorry and thanks.
>
> Beauty is in the eye of the beholder... a truism that applies to
physicists
> as well.
> Reality is ugly in many cases.
>
> However, the mathematical description of reality is considered
beautiful
> when it is concise, succinct, simple and encompassing.
>
> String theory is beautiful in its potential to unify physics... no
> adjustable parameters.
And no testable predictions?
Franz
Thomas Larsson
Jul27-04, 08:52 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no,scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n\n\n\nPeter Woit <woit@cpw.math.columbia.edu> wrote in message news:<cdohtu\\$siv\\$1@newsmaster.cc.columbia.edu>...\n\n> 2d QFT is a fantastic subject, with a lot of examples of beauty and\n> elegance. Often you can write down a very simple 2d QFT, and show\n> that it has a huge amount of very deep and surprising mathematical\n> strucure. Unfortunately these structures don\'t seem to have anything\n> to do with the real world. None of the most beautiful aspects of\n> CFT explain anything about the world,\n\nActually, CFT explains just everything there is to know about phase\ntransitions in 2D. Soft condensed matter is not particle physics, but\nit is certainly part of the real world. Although people usually\ncompare CFT results to computer simulations or exact solutions,\nreal laboratory experiments have been done - a monolayer of argon\natoms on an inert graphite substrate seems to be a favorite system.\n\nSo even if string theory is wrong, the beauty of CFT is not wasted.\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Peter Woit <woit@cpw.math.columbia.edu> wrote in message news:<cdohtu$siv$1@newsmaster.cc.columbia.edu>...
> 2d QFT is a fantastic subject, with a lot of examples of beauty and
> elegance. Often you can write down a very simple 2d QFT, and show
> that it has a huge amount of very deep and surprising mathematical
> strucure. Unfortunately these structures don't seem to have anything
> to do with the real world. None of the most beautiful aspects of
> CFT explain anything about the world,
Actually, CFT explains just everything there is to know about phase
transitions in 2D. Soft condensed matter is not particle physics, but
it is certainly part of the real world. Although people usually
compare CFT results to computer simulations or exact solutions,
real laboratory experiments have been done - a monolayer of argon
atoms on an inert graphite substrate seems to be a favorite system.
So even if string theory is wrong, the beauty of CFT is not wasted.
Esa A E Peuha
Jul28-04, 04:58 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no,scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n\nPeter Woit <woit@cpw.math.columbia.edu> writes:\n\n> 2. As long as you don\'t know what string theory really is, you can\n> keep hoping that it is something truly wonderful and beautiful. The\n> beautiful, elegant theory that string theorists often are referring to\n> is the one they hope exists. Two of Witten\'s definitions of the "M"\n> in M-theory are "Mystery" and "Magic". Much of the beauty of\n> M-theory is the beauty of mystery, of something you don\'t understand\n> that you invest with your hopes and dreams.\n\nThis reminds me a lot about how mathematicians couldn\'t find a way to do\nsome constructions with compass and ruler (trisecting an angle, squaring\na circle, halving a cube) but were convinced that those constructions\nwould turn out to be extremely beautiful and elegant once thay were\ndiscovered. The only problem was that those constructions are provably\nimpossible. I hope the obvious analogy to string theory isn\'t true...\n\n--\nEsa Peuha\nstudent of mathematics at the University of Helsinki\nhttp://www.helsinki.fi/~peuha/\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Peter Woit <woit@cpw.math.columbia.edu> writes:
> 2. As long as you don't know what string theory really is, you can
> keep hoping that it is something truly wonderful and beautiful. The
> beautiful, elegant theory that string theorists often are referring to
> is the one they hope exists. Two of Witten's definitions of the "M"
> in M-theory are "Mystery" and "Magic". Much of the beauty of
> M-theory is the beauty of mystery, of something you don't understand
> that you invest with your hopes and dreams.
This reminds me a lot about how mathematicians couldn't find a way to do
some constructions with compass and ruler (trisecting an angle, squaring
a circle, halving a cube) but were convinced that those constructions
would turn out to be extremely beautiful and elegant once thay were
discovered. The only problem was that those constructions are provably
impossible. I hope the obvious analogy to string theory isn't true...
--
Esa Peuha
student of mathematics at the University of Helsinki
http://www.helsinki.fi/~peuha/
Danny Ross Lunsford
Jul29-04, 05:59 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no,scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n\n\nbackdoorstudent@yahoo.com (backdoorstudent) wrote in message news:<750f5e99.0407211611.61f734a6@posting.google.com>...\n> I ask this seriously and respectfully. And I apologize if it seems\n> like a troll. I always feel uncomfortable when I hear physicists make\n> statements about beauty. Who here thinks reality is ugly?\n> Interestingly, I do not hear mathematicians speak like this as often\n> as I do physicists. So what is it that string theorists find so\n> beautiful? Brian Greene did not convey it to me. Sorry and thanks.\n\nThe beauty in physics is "operational" - by this I mean, the thing\nprogresses by stages, with an old theory settling into a new one in an\nextremely unexpected way that involves bringing in new mathematical\nideas. The end result is usually *simpler* on a conceptual level - and\nthe mathematical expression is usually "tighter", less dependent on\narbitrary assumptions, involving fewer ambiguous objects. The key\npoint is simplification. If we have a complex algebraic expression to\nsimplify, then there is a satisfaction in canceling this and that and\narriving at a simple expression. The same thing happens on a much more\nintense level in physics - to take the example of electrodynamics,\nhere were these two related but self-standing theories, one of magnets\nand the other of currents and charges - by introducing relativity they\nmagically coalesce into a single theory of a new thing, the EM field.\nThis in turn allows one to see the real physical principle in stark\nsimplicity - the conservation of charge. It\'s easy to imagine that the\nintroduction of spacetime and the seeming paradoxes of relativity make\nthings *more* complex, but that\'s not so at all - the final theory is\nfar simpler than the originals, and the apparent complexity is just an\nartifact of trying to interpret the new thing in the old context. The\nsimplification itself gives rise to a new context. It\'s the\nrecognition of the new context that is the "kicker", the "wow" factor\nthat impresses the mind.\n\nThe really huge advances are all like this. If something doesn\'t have\nan immediately perceptible new context along with some kind of\ndramatic simplication of a once thorny issue, then it is not likely to\nbe a fundamental advance.\n\nNote that math is not at all like this (IMO) - math gets more\nbeautiful with generalization, while physics gets more beautiful by\ngetting ever more specific and focused. That is why the exclusively\nmathematical approach to physics, that is, attempts at generalization\nof previous work, rarely succeed (Feynman) - to get to the\nsimplifications requires intuitive leaps that are, in hindsight,\nalmost obvious.\n\nAlso note that "revolutions" in physical thought are fictions. Physics\nis very "evolutionary" - the new develops gradually out of the old, in\nspite of the triumphalist titles given to popularizations. Again (IMO)\nthis is not at all like math - in math brand new things really are\nsometimes just invented on the spot and create a brand new context\nwithout an earlier referent.\n\n-drl\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>backdoorstudent@yahoo.com (backdoorstudent) wrote in message news:<750f5e99.0407211611.61f734a6@posting.google.com>...
> I ask this seriously and respectfully. And I apologize if it seems
> like a troll. I always feel uncomfortable when I hear physicists make
> statements about beauty. Who here thinks reality is ugly?
> Interestingly, I do not hear mathematicians speak like this as often
> as I do physicists. So what is it that string theorists find so
> beautiful? Brian Greene did not convey it to me. Sorry and thanks.
The beauty in physics is "operational" - by this I mean, the thing
progresses by stages, with an old theory settling into a new one in an
extremely unexpected way that involves bringing in new mathematical
ideas. The end result is usually *simpler* on a conceptual level - and
the mathematical expression is usually "tighter", less dependent on
arbitrary assumptions, involving fewer ambiguous objects. The key
point is simplification. If we have a complex algebraic expression to
simplify, then there is a satisfaction in canceling this and that and
arriving at a simple expression. The same thing happens on a much more
intense level in physics - to take the example of electrodynamics,
here were these two related but self-standing theories, one of magnets
and the other of currents and charges - by introducing relativity they
magically coalesce into a single theory of a new thing, the EM field.
This in turn allows one to see the real physical principle in stark
simplicity - the conservation of charge. It's easy to imagine that the
introduction of spacetime and the seeming paradoxes of relativity make
things *more* complex, but that's not so at all - the final theory is
far simpler than the originals, and the apparent complexity is just an
artifact of trying to interpret the new thing in the old context. The
simplification itself gives rise to a new context. It's the
recognition of the new context that is the "kicker", the "wow" factor
that impresses the mind.
The really huge advances are all like this. If something doesn't have
an immediately perceptible new context along with some kind of
dramatic simplication of a once thorny issue, then it is not likely to
be a fundamental advance.
Note that math is not at all like this (IMO) - math gets more
beautiful with generalization, while physics gets more beautiful by
getting ever more specific and focused. That is why the exclusively
mathematical approach to physics, that is, attempts at generalization
of previous work, rarely succeed (Feynman) - to get to the
simplifications requires intuitive leaps that are, in hindsight,
almost obvious.
Also note that "revolutions" in physical thought are fictions. Physics
is very "evolutionary" - the new develops gradually out of the old, in
spite of the triumphalist titles given to popularizations. Again (IMO)
this is not at all like math - in math brand new things really are
sometimes just invented on the spot and create a brand new context
without an earlier referent.
-drl
Lubos Motl
Oct24-04, 06:52 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no,scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>On Sun, 24 Oct 2004, backdoorstudent wrote:\n\n> What\'s so "beautiful" or "elegant" about string theory?\n>\n> I ask this seriously and respectfully. And I apologize if it seems\n> like a troll. I always feel uncomfortable when I hear physicists make\n> statements about beauty. Who here thinks reality is ugly?\n> Interestingly, I do not hear mathematicians speak like this as often\n> as I do physicists. So what is it that string theorists find so\n> beautiful? Brian Greene did not convey it to me. Sorry and thanks.\n\nOf course, I don\'t believe that if Brian failed, I can succeed. ;-) The\nfeeling of beauty in physics is something caused by very objective and\nrational properties of the physical theory, but finally it is an emotional\nfeeling, and if someone just does not have these emotions, it\'s hard to\nconvey them.\n\nBut let me try to answer it anyway.\n\nThe issue of beauty in theoretical physics is very subtle.\n\nFirst of all, the laws behind the Universe are not dumb. If a physicist\ntalks about beauty, she never thinks about "simplicity" of the kind that\nan average teenager who hates math classes at school might appreciate. The\nUniverse is not that simple, and its rules just can\'t be dumb.\n\nAs Einstein said, the laws of the Universe should be as simple as\npossible, but not more.\n\nIn physics, this naive notion of simplicity is often replaced by symmetry.\nSymmetry has something to do with beauty, and it is something that\nconstrains the physical system. If your face has a symmetry, you need to\nknow 1/2 of it only. If a theory respects some symmetries, it proves that\nit is special among other conceivable theories.\n\nIn older theories than string theory, some symmetries must be assumed, and\nthis reduces the number of free parameters and arbitrariness. For example,\nthe Standard Model has less than 30 parameters that describe the strength\nof various interactions (and masses) that are compatible with the given\nsymmetries. In this counting, string theory is maximally constrained - it\nhas no adjustable parameters. One of the first justifications of beauty.\n\nThere are many types of symmetries known in physics - rotational symmetry,\nU(1), SU(2), or SU(3) gauge symmetry, E_8 symmetry, supersymmetry,\nconformal symmetry, and so forth. All of them can be found in string\ntheory, but they always seem to be tiny reflections of something much more\nbeautiful. String theory is something that can start as a small package,\nhowever a package that contains so much good stuff. Moreover, the\nsymmetries can transmute into each other as you walk along the stringy\n"landscape" (I mean moduli space). They can be spontaneously broken,\nunbroken, enhanced, confined.\n\nSymmetric theories don\'t necessarily have to be simple, in the naive\nsense. Eleven-dimensional supergravity is, in some sense, the most\n(super)symmetric field theory, but its Lagrangian is pretty long. A real\nphysicist does not care whether it\'s long or not; a physicist is always\nready to spend an hour by writing a Lagrangian. That\'s not a big deal for\nher, and such superficial questions as time and money don\'t matter. The\nbeauty inside is more important, and eleven-dimensional supergravity has\n32 supersymmetries and other symmetries. There is no rule that beautiful\nobjects must fit one line.\n\nEleven-dimensional supergravity is a part of string theory, a low-energy\nlimit of M-theory in 11 dimensions. There are many potentially beautiful\ntheories in physics, and all of the good ones seem to be connected within\nstring theory. This union is not artificial, and it is another reason that\nmakes it beautiful. You usually find out that string theory can have\nmoduli (exactly massless scalar fields, some sort of dynamical\nparameters), and as you change them, the different theories with different\nsymmetries transform into one another in an exactly controllable and\nunique way.\n\nNevertheless, I don\'t really think that we view the symmetries as the most\nimportant reason why string theory is beautiful. Maybe string theory\'s\npower to naturally include all types of essential and "rigid" physical\nphenomena and derive them from a modest starting point may be a more\naccurate reason behind our claims about "beauty" in string theory. Of\ncourse, this point will not be appreciated by an enemy of reductionism. ;-)\n\nIf someone is not impressed by the fact that a formula (e.g. the\nLagrangian of QED) can explain a large number of physical situations,\nincluding chemistry and animals, as well as the sunset, she can never\nunderstand why the physicists think that string theory is beautiful. From\nthis perspective, string theory is the most advanced achievement of\nreductionism - everything is included in a theory that uniquely and\nnaturally follows from the assumption of a one-dimensional object with\nmeaningful interactions (or from other possible starting points, and\nstring theory now has many). The elementary particles and interactions of\nthe Standard Model are reduced to something even more fundamental -\nsomething that probably cannot be reduced further.\n\nBut I believe that one thing is perhaps even more important for the beauty\nof string theory: the way how it avoids all potential problems.\n\nIf you "glue" a random theory of some type and you try to quantize it, you\nwill be led to many different kinds of diseases that will make the quantum\ntheory unusable. Classical symmetries will be destroyed by quantum effects\n(anomalies). Physical quantities will be expressed by divergent integrals,\nand sometimes the divergences cannot be eliminated, even if you use the\nbest tricks (non-renormalizable theories).\n\nAll these problems always miraculously disappear in string theory. It\'s\nlike in a good movie that keeps you excited, nervous, but eventually leads\nto an unexpected (but reasonable) happy end. It\'s like the Superman who\ncan save the city in time by an unexpected move - except that in string\ntheory, you can prove that these unlikely events are *facts*. You may want\nto invent an "easier" approach than string theory to make the integrals\nconvergent, but such choices will always introduce new problems - such as\nanomalies (or more generally, some breaking of gauge symmetries). String\ntheory just seems to be the only framework where all these problems -\nanomalies and divergences - are avoided. It\'s the only movie with a real\nhappy end. Also, you must think for a while to see why the end is really\nhappy - string theory is not like the cheap movies. It requires you to\nthink, and the beauty can only be appreciated if it works through your\nmind for some time.\n\nPeter Woit finds it unacceptable to work with more than 4 coordinates, so\nhe will prefer movie directors that claim that a movie should only contain\n4 points. He may like these movies, but they are really cheap movies. You\nknow that good movies should really have several dimensions. The movie of\nstring theory is 10 or 11-dimensional, depending on the way how you look\nat it. ;-) Yes, the higher-dimensional geometry itself is beautiful, too.\nIt\'s what distinguishes a sophisticated 3D sculpture from a naive 2D\ncartoon.\n\nBut let me return to the miraculous power of string/M-theory to eliminate\ninconsistencies.\n\nWhat we\'re thinking about is the infinite ocean of "ugly" theories. Each\nof them suffers from a problem. And string/M-theory marches on an\ninfinitely thin road (or string) stretched above this ocean, and its\ncalculations always miraculously combine in such a way that the\npredictions are unique, and they fit together. The detailed features are\nalways "right" so that the result makes sense, even though a single\n"error" would make the theory meaningless.\n\nFinally, string theory is beautiful because of dualities. Take five things\nthat you like - for example, your girlfriend, your favorite bird, a\nphotograph with a sunset above the ocean, your favorite food in a French\nrestaurant, and your new car. ;-) Now imagine an object ST that can be\nobserved from five different directions, or in five different ways of\nthinking. From one vantage point, it will look like your girlfriend, and\nso forth.\n\nYou may think that it is impossible - if something looks like your\ngirlfriend from the left, it can\'t look like a car from another direction.\nSomeone may come with a similar argument in string theory. Nevertheless\nstring theory always brings a set of miracles that make these different\npictures compatible, and therefore it can look like five (or more)\ndifferent beautiful things simultaneously.\n\nString theory is able to change an object to a different object or\nphenomenon smoothly; it is free of any unpredictable singularities. Every\ntime something becomes too singular or sharp and one starts to be afraid\nthat a disaster is looming, string theory always predicts some new objects\nand phenomena that regularize physics and make it as smooth as before.\n\nOK, the beauty is a combination of symmetries and their interplays\n(something that Einstein knows well from his theories of relativity, and\nsomething that underlies the Standard Model too); inevitability and\nuniqueness of the predictions; cancellation of divergences and anomalies\nand the unexpected character of these cancelations; equivalences between\ndifferent ways to look at the theory that eventually turn out to be\ntotally compatible; its natural unification of virtually all other\nimportant phenomena and concepts in quantum field theory and general\nrelativity; its connections to structures in mathematics that are also\ncalled "beautiful" - for example those associated with higher-dimensional\ngeometry (mirror symmetry).\n\nYes, some mathematicians do not talk about "beauty" as often - many of\nthem, in fact, really enjoy if their research is really dry. ;-)\n______________________________________________________________________________\nE-mail: lumo@matfyz.cz fax: +1-617/496-0110 Web: http://lumo.matfyz.cz/\neFax: +1-801/454-1858 work: +1-617/384-9488 home: +1-617/868-4487 (call)\nWebs: http://schwinger.harvard.edu/~motl/ http://motls.blogspot.com/\n^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>On Sun, 24 Oct 2004, backdoorstudent wrote:
> What's so "beautiful" or "elegant" about string theory?
>
> I ask this seriously and respectfully. And I apologize if it seems
> like a troll. I always feel uncomfortable when I hear physicists make
> statements about beauty. Who here thinks reality is ugly?
> Interestingly, I do not hear mathematicians speak like this as often
> as I do physicists. So what is it that string theorists find so
> beautiful? Brian Greene did not convey it to me. Sorry and thanks.
Of course, I don't believe that if Brian failed, I can succeed. ;-) The
feeling of beauty in physics is something caused by very objective and
rational properties of the physical theory, but finally it is an emotional
feeling, and if someone just does not have these emotions, it's hard to
convey them.
But let me try to answer it anyway.
The issue of beauty in theoretical physics is very subtle.
First of all, the laws behind the Universe are not dumb. If a physicist
talks about beauty, she never thinks about "simplicity" of the kind that
an average teenager who hates math classes at school might appreciate. The
Universe is not that simple, and its rules just can't be dumb.
As Einstein said, the laws of the Universe should be as simple as
possible, but not more.
In physics, this naive notion of simplicity is often replaced by symmetry.
Symmetry has something to do with beauty, and it is something that
constrains the physical system. If your face has a symmetry, you need to
know 1/2 of it only. If a theory respects some symmetries, it proves that
it is special among other conceivable theories.
In older theories than string theory, some symmetries must be assumed, and
this reduces the number of free parameters and arbitrariness. For example,
the Standard Model has less than 30 parameters that describe the strength
of various interactions (and masses) that are compatible with the given
symmetries. In this counting, string theory is maximally constrained - it
has no adjustable parameters. One of the first justifications of beauty.
There are many types of symmetries known in physics - rotational symmetry,
U(1), SU(2), or SU(3) gauge symmetry, E_8 symmetry, supersymmetry,
conformal symmetry, and so forth. All of them can be found in string
theory, but they always seem to be tiny reflections of something much more
beautiful. String theory is something that can start as a small package,
however a package that contains so much good stuff. Moreover, the
symmetries can transmute into each other as you walk along the stringy
"landscape" (I mean moduli space). They can be spontaneously broken,
unbroken, enhanced, confined.
Symmetric theories don't necessarily have to be simple, in the naive
sense. Eleven-dimensional supergravity is, in some sense, the most
(super)symmetric field theory, but its Lagrangian is pretty long. A real
physicist does not care whether it's long or not; a physicist is always
ready to spend an hour by writing a Lagrangian. That's not a big deal for
her, and such superficial questions as time and money don't matter. The
beauty inside is more important, and eleven-dimensional supergravity has
32 supersymmetries and other symmetries. There is no rule that beautiful
objects must fit one line.
Eleven-dimensional supergravity is a part of string theory, a low-energy
limit of M-theory in 11 dimensions. There are many potentially beautiful
theories in physics, and all of the good ones seem to be connected within
string theory. This union is not artificial, and it is another reason that
makes it beautiful. You usually find out that string theory can have
moduli (exactly massless scalar fields, some sort of dynamical
parameters), and as you change them, the different theories with different
symmetries transform into one another in an exactly controllable and
unique way.
Nevertheless, I don't really think that we view the symmetries as the most
important reason why string theory is beautiful. Maybe string theory's
power to naturally include all types of essential and "rigid" physical
phenomena and derive them from a modest starting point may be a more
accurate reason behind our claims about "beauty" in string theory. Of
course, this point will not be appreciated by an enemy of reductionism. ;-)
If someone is not impressed by the fact that a formula (e.g. the
Lagrangian of QED) can explain a large number of physical situations,
including chemistry and animals, as well as the sunset, she can never
understand why the physicists think that string theory is beautiful. From
this perspective, string theory is the most advanced achievement of
reductionism - everything is included in a theory that uniquely and
naturally follows from the assumption of a one-dimensional object with
meaningful interactions (or from other possible starting points, and
string theory now has many). The elementary particles and interactions of
the Standard Model are reduced to something even more fundamental -
something that probably cannot be reduced further.
But I believe that one thing is perhaps even more important for the beauty
of string theory: the way how it avoids all potential problems.
If you "glue" a random theory of some type and you try to quantize it, you
will be led to many different kinds of diseases that will make the quantum
theory unusable. Classical symmetries will be destroyed by quantum effects
(anomalies). Physical quantities will be expressed by divergent integrals,
and sometimes the divergences cannot be eliminated, even if you use the
best tricks (non-renormalizable theories).
All these problems always miraculously disappear in string theory. It's
like in a good movie that keeps you excited, nervous, but eventually leads
to an unexpected (but reasonable) happy end. It's like the Superman who
can save the city in time by an unexpected move - except that in string
theory, you can prove that these unlikely events are *facts*. You may want
to invent an "easier" approach than string theory to make the integrals
convergent, but such choices will always introduce new problems - such as
anomalies (or more generally, some breaking of gauge symmetries). String
theory just seems to be the only framework where all these problems -
anomalies and divergences - are avoided. It's the only movie with a real
happy end. Also, you must think for a while to see why the end is really
happy - string theory is not like the cheap movies. It requires you to
think, and the beauty can only be appreciated if it works through your
mind for some time.
Peter Woit finds it unacceptable to work with more than 4 coordinates, so
he will prefer movie directors that claim that a movie should only contain
4 points. He may like these movies, but they are really cheap movies. You
know that good movies should really have several dimensions. The movie of
string theory is 10 or 11-dimensional, depending on the way how you look
at it. ;-) Yes, the higher-dimensional geometry itself is beautiful, too.
It's what distinguishes a sophisticated 3D sculpture from a naive 2D
cartoon.
But let me return to the miraculous power of string/M-theory to eliminate
inconsistencies.
What we're thinking about is the infinite ocean of "ugly" theories. Each
of them suffers from a problem. And string/M-theory marches on an
infinitely thin road (or string) stretched above this ocean, and its
calculations always miraculously combine in such a way that the
predictions are unique, and they fit together. The detailed features are
always "right" so that the result makes sense, even though a single
"error" would make the theory meaningless.
Finally, string theory is beautiful because of dualities. Take five things
that you like - for example, your girlfriend, your favorite bird, a
photograph with a sunset above the ocean, your favorite food in a French
restaurant, and your new car. ;-) Now imagine an object ST that can be
observed from five different directions, or in five different ways of
thinking. From one vantage point, it will look like your girlfriend, and
so forth.
You may think that it is impossible - if something looks like your
girlfriend from the left, it can't look like a car from another direction.
Someone may come with a similar argument in string theory. Nevertheless
string theory always brings a set of miracles that make these different
pictures compatible, and therefore it can look like five (or more)
different beautiful things simultaneously.
String theory is able to change an object to a different object or
phenomenon smoothly; it is free of any unpredictable singularities. Every
time something becomes too singular or sharp and one starts to be afraid
that a disaster is looming, string theory always predicts some new objects
and phenomena that regularize physics and make it as smooth as before.
OK, the beauty is a combination of symmetries and their interplays
(something that Einstein knows well from his theories of relativity, and
something that underlies the Standard Model too); inevitability and
uniqueness of the predictions; cancellation of divergences and anomalies
and the unexpected character of these cancelations; equivalences between
different ways to look at the theory that eventually turn out to be
totally compatible; its natural unification of virtually all other
important phenomena and concepts in quantum field theory and general
relativity; its connections to structures in mathematics that are also
called "beautiful" - for example those associated with higher-dimensional
geometry (mirror symmetry).
Yes, some mathematicians do not talk about "beauty" as often - many of
them, in fact, really enjoy if their research is really dry. ;-)
__{____________________________________________________________________________}
E-mail: lumo@matfyz.cz fax: +1-617/496-0110 Web: http://lumo.matfyz.cz/
eFax: +1-801/454-1858 work: +1-617/384-9488 home: +1-617/868-4487 (call)
Webs: http://schwinger.harvard.edu/~motl/ http://motls.blogspot.com/
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Doug Sweetser
Oct28-04, 02:29 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no,scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n\n\nHello Lubos:\n\n> On Sun, 24 Oct 2004, backdoorstudent wrote:\n>\n>> What\'s so "beautiful" or "elegant" about string theory?\n\nI bought the DVD and looked for the elegant equations. The few I found\ndid not make a strong case for the thesis.\n\n\n> First of all, the laws behind the Universe are not dumb.\n\nPerhaps instead of "dumb", backdoorstudent should have said something\nabout "no thought involved" or "necessarily automatic". Fundamental\nparticles are labeled that due to their simplicity. We don\'t understand\nall the rules or logic, but no particles are making tricky calculations\nvery rapidly.\n\n\n> If someone is not impressed by the fact that a formula (e.g. the\n> Lagrangian of QED) can explain a large number of physical situations,\n> including chemistry and animals, as well as the sunset, she can never\n> understand why the physicists think that string theory is beautiful.\n\nFor me, the focus should be on Lagrange densities, so lets write out\nexplicitly some that are gorgeous. Here is the Lagrange density for\ngeneral relativity in a vacuum:\n\nL = (-g)^(1/2) R\n\nwhere\ng is the determinant of the metric tensor\nR is the Ricci scalar\n\nVary the action with respect to the metric tensor, and Einstein\'s field\nequations results. It is all about the how the connection varies,\nthere is nothing else. There is a problem of completeness, or\nconnections to other aspects of physics, because this metric is only\nabout how spacetime geometry changes.\n\nCase two, already cited, EM, but I\'ll do the classical form in a vacuum:\n\nL = -(d^u A^v - d^v A^u)(d_u A_v - d_v A_u)\n\nVary the action with respect to the potential and you get the Maxwell\nequations in a vacuum. It is all about the potential. Because this\ntensor uses the exterior derivative, it is silent on the connection,\nhow the metric changes. This is why the metric and connection must be\nsupplied to solve any problems in EM, although a flat metric and a\nconnection that is torsion-free and metric compatible is usually\nassumed (nothing dictates this must be so).\n\nI am one of the few people posting to the newsgroup to write out the\nstandard model Lagrange density explicitly. Here it is again:\n\nL = g_mu_nu phi* gamma^mu D^nu phi\n\nwhere D^nu = d^nu - i k_EM Y/2 A^nu - i k_weak tau^i/2 W^i^nu\n- i k_strong lambda^j/2 G^j^nu\ni goes from 1-3, j from 1-8\nk_EM, k_weak, and k_strong are coupling constants.\nY, tau^i, and lambda^j generate U(1), SU(2), and SU(3).\nA^nu, W^i^nu, and G^j^nu are potentials.\n\nDifferent symmetries are brought in in similar fashion. The aspect that\nfeels incomplete is why Nature decided to use U(1), SU(2), and SU(3)\nbut not some other combination. Still, who can argue with success?\n\nSo Lubos, that brings me to a question for you. I would like to see one\nof these "pretty long" Lagrangians in 11 dimensions. Please try to\nlabel all the parts that go into it as I did for the standard model\nLagrangian. I realize this is an ongoing area of research, so there is\nno consensus on which particular one to write out, I just would like to\nsee one of the 11D Lagrange densities as part of my continuing\neducation in string theory.\n\n\ndoug\nquaternions.com\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Hello Lubos:
> On Sun, 24 Oct 2004, backdoorstudent wrote:
>
>> What's so "beautiful" or "elegant" about string theory?
I bought the DVD and looked for the elegant equations. The few I found
did not make a strong case for the thesis.
> First of all, the laws behind the Universe are not dumb.
Perhaps instead of "dumb", backdoorstudent should have said something
about "no thought involved" or "necessarily automatic". Fundamental
particles are labeled that due to their simplicity. We don't understand
all the rules or logic, but no particles are making tricky calculations
very rapidly.
> If someone is not impressed by the fact that a formula (e.g. the
> Lagrangian of QED) can explain a large number of physical situations,
> including chemistry and animals, as well as the sunset, she can never
> understand why the physicists think that string theory is beautiful.
For me, the focus should be on Lagrange densities, so lets write out
explicitly some that are gorgeous. Here is the Lagrange density for
general relativity in a vacuum:
L = (-g)^(1/2) R
where
g is the determinant of the metric tensor
R is the Ricci scalar
Vary the action with respect to the metric tensor, and Einstein's field
equations results. It is all about the how the connection varies,
there is nothing else. There is a problem of completeness, or
connections to other aspects of physics, because this metric is only
about how spacetime geometry changes.
Case two, already cited, EM, but I'll do the classical form in a vacuum:
L = -(d^u A^v - d^v A^u)(d_u A_v - d_v A_u)
Vary the action with respect to the potential and you get the Maxwell
equations in a vacuum. It is all about the potential. Because this
tensor uses the exterior derivative, it is silent on the connection,
how the metric changes. This is why the metric and connection must be
supplied to solve any problems in EM, although a flat metric and a
connection that is torsion-free and metric compatible is usually
assumed (nothing dictates this must be so).
I am one of the few people posting to the newsgroup to write out the
standard model Lagrange density explicitly. Here it is again:
L = g_{mu_nu} \phi* \gamma^\mu D^\nu \phi
where D^\nu = d^\nu - i k_{EM} Y/2 A^\nu - i k_{weak} \tau^i/2 W^i^\nu- i k_{strong} \lambda^j/2 G^j^\nu
i goes from 1-3, j from 1-8
k_{EM}, k_{weak}, and k_{strong} are coupling constants.
Y, \tau^i, and \lambda^j generate U(1), SU(2), and SU(3).
A^\nu, W^i^\nu, and G^j^\nu are potentials.
Different symmetries are brought in in similar fashion. The aspect that
feels incomplete is why Nature decided to use U(1), SU(2), and SU(3)
but not some other combination. Still, who can argue with success?
So Lubos, that brings me to a question for you. I would like to see one
of these "pretty long" Lagrangians in 11 dimensions. Please try to
label all the parts that go into it as I did for the standard model
Lagrangian. I realize this is an ongoing area of research, so there is
no consensus on which particular one to write out, I just would like to
see one of the 11D Lagrange densities as part of my continuing
education in string theory.
doug
quaternions.com
backdoorstudent
Oct29-04, 03:07 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no,scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n\n\n\nDoug Sweetser <sweetser@alum.mit.edu> wrote in message news:<clqlfl\\$7a1\\$1@pcls4.std.com>...\n> Hello Lubos:\n>\n> > On Sun, 24 Oct 2004, backdoorstudent wrote:\n> >\n> >> What\'s so "beautiful" or "elegant" about string theory?\n>\n> I bought the DVD and looked for the elegant equations. The few I found\n> did not make a strong case for the thesis.\n>\n>\n> > First of all, the laws behind the Universe are not dumb.\n>\n> Perhaps instead of "dumb", backdoorstudent should have said something\n> about "no thought involved" or "necessarily automatic".\n\nI never said any such thing; that was Lubos putting words in my mouth.\nNevertheless, I would say that it\'s dumb to call the laws of nature\ndumb (or smart).\n\nIf my opinion matters, -it doesn\'t, yet I cannot resist sharing it:)-\nit is that the laws of the universe are completely indifferent to our\npresumptions of beauty. Physicists love to romanticize about their\nsense of beauty leading the way and repeatedly quote and make\nreference to Einstein and his intellectual methods to support this\nthesis. But the history of science reflects a much more mundane and\ntortured endeavor based mostly on curiosity and common sense rather\nthan aesthetics. This is what leads me to feel that all this blather\nabout beauty and elegance is nothing more than pontification.\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Doug Sweetser <sweetser@alum.mit.edu> wrote in message news:<clqlfl$7a1$1@pcls4.std.com>...
> Hello Lubos:
>
> > On Sun, 24 Oct 2004, backdoorstudent wrote:
> >
> >> What's so "beautiful" or "elegant" about string theory?
>
> I bought the DVD and looked for the elegant equations. The few I found
> did not make a strong case for the thesis.
>
>
> > First of all, the laws behind the Universe are not dumb.
>
> Perhaps instead of "dumb", backdoorstudent should have said something
> about "no thought involved" or "necessarily automatic".
I never said any such thing; that was Lubos putting words in my mouth.
Nevertheless, I would say that it's dumb to call the laws of nature
dumb (or smart).
If my opinion matters, -it doesn't, yet I cannot resist sharing it:)-
it is that the laws of the universe are completely indifferent to our
presumptions of beauty. Physicists love to romanticize about their
sense of beauty leading the way and repeatedly quote and make
reference to Einstein and his intellectual methods to support this
thesis. But the history of science reflects a much more mundane and
tortured endeavor based mostly on curiosity and common sense rather
than aesthetics. This is what leads me to feel that all this blather
about beauty and elegance is nothing more than pontification.
Lubos Motl
Oct30-04, 06:16 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no,scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>On Fri, 29 Oct 2004, backdoorstudent wrote:\n\n> backdoorstudent: What\'s so "beautiful" or "elegant" about string theory?\n>\n> > Lubos Motl: First of all, the laws behind the Universe are not dumb.\n>\n> backdoorstudent: I never said any such thing; that was Lubos putting\n> words in my mouth. Nevertheless, I would say that it\'s dumb to call the\n> laws of nature dumb (or smart).\n\nI was also surprised when someone confiscated my quote. ;-) Incidentally,\nthe laws of Nature are pretty smart, and it\'s dumb if someone does not see\nit, and even more dumb if someone says that they are *not* smart. They are\nsmarter than we are, and string theory seems to be smarter yet.\n\nI was not putting anything in your mouth. Instead, I was seriously writing\nan important fact about the physical laws - and the only relation to you\nis that I was trying to answer your question "What\'s beauty in physics and\nstring theory". Sorry for any potential contributions of mine to the\nmisunderstanding.\n\nThe context of my sentence was that the laws of physics are not "simple"\nin the naive sense - i.e. simple from the viewpoint of a teenager who\nhates math. The beauty of the laws of Nature requires some intelligence\nand research to be appreciated.\n\n> If my opinion matters, -it doesn\'t, yet I cannot resist sharing it:)-\n> it is that the laws of the universe are completely indifferent to our\n> presumptions of beauty.\n\nI agree with that. They are indifferent - and they are beautiful. ;-)\n\n> Physicists love to romanticize about their\n> sense of beauty leading the way and repeatedly quote and make\n> reference to Einstein and his intellectual methods to support this\n> thesis.\n\nRight. Einstein, Dirac, and others were the people who started to\nemphasize beauty of the physical laws, and all of us are just followers,\nin a sense. But of course, it\'s not quite the same type of beauty that\nartists appreciate and create - or the beauty of women that attracts men.\n\nThe beauty of the laws of Nature is a very rational thing - at the very\nend, XY\'s statement that the laws are beautiful really means that the laws\nmake sense to XY, and they fit together, and XY sort of understands them\nand can remember them - much like a smooth shape of a beautiful object (or\nsubject). The other people, those who do *not* understand the laws of\nNature, also don\'t appreciate their beauty. As long as something looks\nconvoluted and unnatural to me, I won\'t say that it\'s beautiful.\n\n> But the history of science reflects a much more mundane and\n> tortured endeavor based mostly on curiosity and common sense rather\n> than aesthetics. This is what leads me to feel that all this blather\n> about beauty and elegance is nothing more than pontification.\n\nYou don\'t seem to appreciate how amazing it is that the world satisfies\nsome simple enough comprehensible laws at all. Einstein said that the most\nincomprehensible thing about the world is that it is comprehensible. If\nthe laws of Nature were something that a theoretical physicist would call\n"ugly", it would be pretty difficult to find out how they exactly work -\nbecause this "ugliness" really means that the theories would not be\nrobust, and there would be too many arbitrary components in them.\n______________________________________________________________________________\nE-mail: lumo@matfyz.cz fax: +1-617/496-0110 Web: http://lumo.matfyz.cz/\neFax: +1-801/454-1858 work: +1-617/384-9488 home: +1-617/868-4487 (call)\nWebs: http://schwinger.harvard.edu/~motl/ http://motls.blogspot.com/\n^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>On Fri, 29 Oct 2004, backdoorstudent wrote:
> backdoorstudent: What's so "beautiful" or "elegant" about string theory?
>
> > Lubos Motl: First of all, the laws behind the Universe are not dumb.
>
> backdoorstudent: I never said any such thing; that was Lubos putting
> words in my mouth. Nevertheless, I would say that it's dumb to call the
> laws of nature dumb (or smart).
I was also surprised when someone confiscated my quote. ;-) Incidentally,
the laws of Nature are pretty smart, and it's dumb if someone does not see
it, and even more dumb if someone says that they are *not* smart. They are
smarter than we are, and string theory seems to be smarter yet.
I was not putting anything in your mouth. Instead, I was seriously writing
an important fact about the physical laws - and the only relation to you
is that I was trying to answer your question "What's beauty in physics and
string theory". Sorry for any potential contributions of mine to the
misunderstanding.
The context of my sentence was that the laws of physics are not "simple"
in the naive sense - i.e. simple from the viewpoint of a teenager who
hates math. The beauty of the laws of Nature requires some intelligence
and research to be appreciated.
> If my opinion matters, -it doesn't, yet I cannot resist sharing it:)-
> it is that the laws of the universe are completely indifferent to our
> presumptions of beauty.
I agree with that. They are indifferent - and they are beautiful. ;-)
> Physicists love to romanticize about their
> sense of beauty leading the way and repeatedly quote and make
> reference to Einstein and his intellectual methods to support this
> thesis.
Right. Einstein, Dirac, and others were the people who started to
emphasize beauty of the physical laws, and all of us are just followers,
in a sense. But of course, it's not quite the same type of beauty that
artists appreciate and create - or the beauty of women that attracts men.
The beauty of the laws of Nature is a very rational thing - at the very
end, XY's statement that the laws are beautiful really means that the laws
make sense to XY, and they fit together, and XY sort of understands them
and can remember them - much like a smooth shape of a beautiful object (or
subject). The other people, those who do *not* understand the laws of
Nature, also don't appreciate their beauty. As long as something looks
convoluted and unnatural to me, I won't say that it's beautiful.
> But the history of science reflects a much more mundane and
> tortured endeavor based mostly on curiosity and common sense rather
> than aesthetics. This is what leads me to feel that all this blather
> about beauty and elegance is nothing more than pontification.
You don't seem to appreciate how amazing it is that the world satisfies
some simple enough comprehensible laws at all. Einstein said that the most
incomprehensible thing about the world is that it is comprehensible. If
the laws of Nature were something that a theoretical physicist would call
"ugly", it would be pretty difficult to find out how they exactly work -
because this "ugliness" really means that the theories would not be
robust, and there would be too many arbitrary components in them.
__{____________________________________________________________________________}
E-mail: lumo@matfyz.cz fax: +1-617/496-0110 Web: http://lumo.matfyz.cz/
eFax: +1-801/454-1858 work: +1-617/384-9488 home: +1-617/868-4487 (call)
Webs: http://schwinger.harvard.edu/~motl/ http://motls.blogspot.com/
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Lubos Motl
Oct30-04, 06:42 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no,scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>On Thu, 28 Oct 2004, Doug Sweetser wrote:\n\n> I bought the DVD and looked for the elegant equations. The few I found\n> did not make a strong case for the thesis.\n\nThe document on PBS has been created for regular viewers, so it does not\ncover any math - except for potential anomalies in 1+1=2 and 31x16=496,\nand except for Einstein\'s equations and the Euler beta function (Veneziano\namplitude) which are not really explained. ;-) I thought it was\ncomprehensible that the document was not created for physics PhD students\nor professionals. :-)\n\n> > L.M.: First of all, the laws behind the Universe are not dumb.\n>\n> Perhaps instead of "dumb", backdoorstudent should have said something\n> about "no thought involved" or "necessarily automatic".\n\nIt was my statement, not backdoorstudent\'s statement, as we now explain in\ntwo other postings.\n\n> Fundamental particles are labeled that due to their simplicity.\n\nElementary particles are called elementary because according to the most\ncurrent theory that describes them (and their interactions), namely the\nStandard Model, they have no internal structure. In string theory, they\nwould not be quite elementary, but we tolerate the term anyway. ;-)\n\n> ... We don\'t understand all the rules or logic, ...\n\nWhich rules of logic do you precisely misunderstand? We may be able to\nhelp you. ;-)\n\n> but no particles are making tricky calculations very rapidly.\n\nApologies for I don\'t quite understand this sentence.\n\n> For me, the focus should be on Lagrange densities, ...\n\nThe whole of string theory probably cannot be written as a simple\nLagrangian density in spacetime.\n\n> L = (-g)^(1/2) R\n\nThis is the 1915 type of beauty, but in 2004 we\'re a bit further.\n\n> L = -(d^u A^v - d^v A^u)(d_u A_v - d_v A_u)\n\nThat\'s a 1864-style beauty.\n\n> Different symmetries are brought in in similar fashion. The aspect that\n> feels incomplete is why Nature decided to use U(1), SU(2), ...\n\n1969.\n\n> and SU(3) ...\n\n1974.\n\n> ... but not some other combination.\n\nWe can eliminate many other combinations because they would be anomalous,\nbut something is missing. String theory is the only framework with the\ncapacity to answer such questions about the gauge groups, but it has not\ndone it yet.\n\n> So Lubos, that brings me to a question for you. I would like to see one\n> of these "pretty long" Lagrangians in 11 dimensions.\n\nOnce again, local field theories with Lagrangians for a finite number of\nfields in spacetime are just approximations of string theory at long\ndistances. At general distances, string theory predicts an infinite number\nof new fields, phenomena, and their precise structure.\n\nThe only Lagrangian in large 11 dimensions worth your time is the\nLagrangian of 11-dimensional supergravity - which is more beautiful, in a\nphysics counting, than just general relativity - because it has not only\ngeneral covariance, but also local supersymmetry. But in a sense, it is\njust some Lagrangian - a generalization of your GR and Maxwell\'s system,\nplus some fermions. See e.g. the original paper by Cremmer+Julia+Scherk\n\nhttp://ccdb3fs.kek.jp/cgi-bin/img_index?7805106\n\nor one of its citations or the textbooks on SUGRA or string theory - for\nexample volumes II of Polchinski\'s "String Theory" (page 85) or\nGreen+Schwarz+Witten "Superstring theory".\n\nThe bosonic part of the Lagrangian has 11D version of \\sqrt(g).R, as in\nGeneral Relativity, plus |F(4)|^2, where F(4) is the completely\nantisymmetric tensor with 4 indices (4-form), plus C(3) /\\ F(4) /\\ F(4) / 6,\nwhere C(3) is the 3-form potential for the 4-form F(4). The last term is\ncalled the Chern-Simons term, and it is required by supersymmetry. There\nare also the fermionic terms for the gravitino - psi^a_\\mu with one spinor\nindex and one vector index (gravitino is spin 3/2, in the 4-dimensional\nlanguage). The gravitino psi also couples to the field strength F(4), and\nthere is also a quartic term of the form psi^4, with some contractions.\nAll this structure is completely determined by supersymmetry.\n\nThe exact physics of M-theory at all energies can also be described by a\nLagrangian - of the large N BFSS matrix model\n\nhttp://arxiv.org/abs/hep-th/9610043\n\n> Please try to label all the parts that go into it as I did for the\n> standard model Lagrangian. I realize this is an ongoing area of\n> research, so there is no consensus on which particular one to write\n> out, I just would like to see one of the 11D Lagrange densities as\n> part of my continuing education in string theory.\n\nThere is only one meaningful SUSY Lagrangian in 11 dimensions, and it is\njust too long to write it again, and therefore I referred to literature.\nRealistic models based on 11-dimensional M-theory are obtained by\ncompactifying the M-theory on a singular 7-dimensional manifold of G2\nholonomy.\n______________________________________________________________________________\nE-mail: lumo@matfyz.cz fax: +1-617/496-0110 Web: http://lumo.matfyz.cz/\neFax: +1-801/454-1858 work: +1-617/384-9488 home: +1-617/868-4487 (call)\nWebs: http://schwinger.harvard.edu/~motl/ http://motls.blogspot.com/\n^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>On Thu, 28 Oct 2004, Doug Sweetser wrote:
> I bought the DVD and looked for the elegant equations. The few I found
> did not make a strong case for the thesis.
The document on PBS has been created for regular viewers, so it does not
cover any math - except for potential anomalies in 1+1=2 and 31x16=496,
and except for Einstein's equations and the Euler \beta function (Veneziano
amplitude) which are not really explained. ;-) I thought it was
comprehensible that the document was not created for physics PhD students
or professionals. :-)
> > L.M.: First of all, the laws behind the Universe are not dumb.
>
> Perhaps instead of "dumb", backdoorstudent should have said something
> about "no thought involved" or "necessarily automatic".
It was my statement, not backdoorstudent's statement, as we now explain in
two other postings.
> Fundamental particles are labeled that due to their simplicity.
Elementary particles are called elementary because according to the most
current theory that describes them (and their interactions), namely the
Standard Model, they have no internal structure. In string theory, they
would not be quite elementary, but we tolerate the term anyway. ;-)
> ... We don't understand all the rules or logic, ...
Which rules of logic do you precisely misunderstand? We may be able to
help you. ;-)
> but no particles are making tricky calculations very rapidly.
Apologies for I don't quite understand this sentence.
> For me, the focus should be on Lagrange densities, ...
The whole of string theory probably cannot be written as a simple
Lagrangian density in spacetime.
> L = (-g)^(1/2) R
This is the 1915 type of beauty, but in 2004 we're a bit further.
> L = -(d^u A^v - d^v A^u)(d_u A_v - d_v A_u)
That's a 1864-style beauty.
> Different symmetries are brought in in similar fashion. The aspect that
> feels incomplete is why Nature decided to use U(1), SU(2), ...
1969.
> and SU(3) ...
1974.
> ... but not some other combination.
We can eliminate many other combinations because they would be anomalous,
but something is missing. String theory is the only framework with the
capacity to answer such questions about the gauge groups, but it has not
done it yet.
> So Lubos, that brings me to a question for you. I would like to see one
> of these "pretty long" Lagrangians in 11 dimensions.
Once again, local field theories with Lagrangians for a finite number of
fields in spacetime are just approximations of string theory at long
distances. At general distances, string theory predicts an infinite number
of new fields, phenomena, and their precise structure.
The only Lagrangian in large 11 dimensions worth your time is the
Lagrangian of 11-dimensional supergravity - which is more beautiful, in a
physics counting, than just general relativity - because it has not only
general covariance, but also local supersymmetry. But in a sense, it is
just some Lagrangian - a generalization of your GR and Maxwell's system,
plus some fermions. See e.g. the original paper by Cremmer+Julia+Scherk
http://ccdb3fs.kek.jp/cgi-bin/img_index?7805106
or one of its citations or the textbooks on SUGRA or string theory - for
example volumes II of Polchinski's "String Theory" (page 85) or
Green+Schwarz+Witten "Superstring theory".
The bosonic part of the Lagrangian has 11D version of \sqrt(g).R, as in
General Relativity, plus |F(4)|^2, where F(4) is the completely
antisymmetric tensor with 4 indices (4-form), plus C(3) /\ F(4) /\ F(4) / 6,
where C(3) is the 3-form potential for the 4-form F(4). The last term is
called the Chern-Simons term, and it is required by supersymmetry. There
are also the fermionic terms for the gravitino - \psi^a_\mu with one spinor
index and one vector index (gravitino is spin 3/2, in the 4-dimensional
language). The gravitino \psi also couples to the field strength F(4), and
there is also a quartic term of the form \psi^4, with some contractions.
All this structure is completely determined by supersymmetry.
The exact physics of M-theory at all energies can also be described by a
Lagrangian - of the large N BFSS matrix model
> Please try to label all the parts that go into it as I did for the
> standard model Lagrangian. I realize this is an ongoing area of
> research, so there is no consensus on which particular one to write
> out, I just would like to see one of the 11D Lagrange densities as
> part of my continuing education in string theory.
There is only one meaningful SUSY Lagrangian in 11 dimensions, and it is
just too long to write it again, and therefore I referred to literature.
Realistic models based on 11-dimensional M-theory are obtained by
compactifying the M-theory on a singular 7-dimensional manifold of G2
holonomy.
__{____________________________________________________________________________}
E-mail: lumo@matfyz.cz fax: +1-617/496-0110 Web: http://lumo.matfyz.cz/
eFax: +1-801/454-1858 work: +1-617/384-9488 home: +1-617/868-4487 (call)
Webs: http://schwinger.harvard.edu/~motl/ http://motls.blogspot.com/
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
backdoorstudent
Nov2-04, 01:38 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no,scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>\n\n\n\nLubos Motl <motl@feynman.harvard.edu> wrote in message news:<Pine.LNX.4.31.0410301801160.20931-100000@feynman.harvard.edu>...\n> You don\'t seem to appreciate how amazing it is that the world satisfies\n> some simple enough comprehensible laws at all.\n\nOf course I do. I think almost everybody reading this newsgroup does.\n\n> Einstein said that the most incomprehensible thing about the world is that it is comprehensible.\n\nI know. And I\'m getting sick of hearing everybody parrot it around as\ntheir mantra. And if you insist on presuming that it must be that way\nyou may miss out on finding out something more accurate about the\nworld. Because our experience of the world being this way is a very\nshort one so far, and it is an idealist extrapolation to think it will\ncontinue forever. I am not saying I believe it won\'t. I\'m just saying\nkeep your mind open to other possibilties.\n\nWould you really be surprised if the world was ultimately\nincomprehensible?\n\n> If the laws of Nature were something that a theoretical physicist would call\n> "ugly", it would be pretty difficult to find out how they exactly work -\n> because this "ugliness" really means that the theories would not be\n> robust, and there would be too many arbitrary components in them.\n\nIf this is really what you mean by "ugliness" then it looks to me as\nthough we have indeed reached that place of being not robust with too\nmany arbitrary components. Am I wrong?\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Lubos Motl <motl@feynman.harvard.edu> wrote in message news:<Pine.LNX.4.31.0410301801160.20931-100000@feynman.harvard.edu>...
> You don't seem to appreciate how amazing it is that the world satisfies
> some simple enough comprehensible laws at all.
Of course I do. I think almost everybody reading this newsgroup does.
> Einstein said that the most incomprehensible thing about the world is that it is comprehensible.
I know. And I'm getting sick of hearing everybody parrot it around as
their mantra. And if you insist on presuming that it must be that way
you may miss out on finding out something more accurate about the
world. Because our experience of the world being this way is a very
short one so far, and it is an idealist extrapolation to think it will
continue forever. I am not saying I believe it won't. I'm just saying
keep your mind open to other possibilties.
Would you really be surprised if the world was ultimately
incomprehensible?
> If the laws of Nature were something that a theoretical physicist would call
> "ugly", it would be pretty difficult to find out how they exactly work -
> because this "ugliness" really means that the theories would not be
> robust, and there would be too many arbitrary components in them.
If this is really what you mean by "ugliness" then it looks to me as
though we have indeed reached that place of being not robust with too
many arbitrary components. Am I wrong?
John Gonsowski
Nov3-04, 10:59 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no,scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Doug Sweetser <sweetser@alum.mit.edu> wrote in message news:<clqlfl\\$7a1\\$1@pcls4.std.com>...\n> So Lubos, that brings me to a question for you. I would like to see one\n> of these "pretty long" Lagrangians in 11 dimensions. Please try to\n> label all the parts that go into it as I did for the standard model\n> Lagrangian. I realize this is an ongoing area of research, so there is\n> no consensus on which particular one to write out, I just would like to\n> see one of the 11D Lagrange densities as part of my continuing\n> education in string theory.\n>\n>\n> doug\n> quaternions.com\n\nHere is Tony Smith\'s very well labeled Lagrangian for bosonic string\ntheory, I\'m curious as to what you think of it:\n\nthe Integral over the Cl(1,7) vector 1+7=8-dimensional SpaceTime of\n\ndd P\' /\\ * dd P + F /\\ *F + S\' D S + GF + GG\nwhere\n\nd is the 8-dim covariant derivative\nP is the scalar field\nF is the adjoint Spin(8) curvature\nS\' and S are half-spinor fermion spaces\nD is the 8-dim Dirac operator\nGF is the gauge-fixing term\nGG is the ghost term,\nplus a topological Pontrjagin term.\n\nThe Pontrjagin term represents Instantons in 8-dimensional spacetime\nthat is locally RP1 x S7. Since, after dimensional reduction of\nspacetime from 8 to 4 dimensions, the Pontrjagin term goes into the\nSpin(6) conformal gravity sector of the D4-D5-E6-E7-E8 VoDou physics\nmodel, it does not go to the SU(3) color force sector. Therefore, the\nSU(3) color force Sector has no THETA-term and the D4-D5-E6-E7-E8\nVodou Physics model has no theoretical THETA-CP problem.\n\nAfter dimensional reduction to 4-dimensional spacetime, the S7 of RP1\nx S7 is factored by the Hopf fibration S3 -> S7 -> S4 into\n4-dimensional spacetime that is locally RP1 x S3, plus a CP2 part\nrelated to 4-dimensional Internal Symmetry Space.\n\nReduction also produces, for each World of the Many-Worlds, a\n4-dimensional lattice Spacetime with MacDowell-Mansouri Gravity, a\nHiggs Mechanism, and a Complex Propagator Phase;\n\na 4-dimensional lattice Internal Symmetry Space with 8 Color Force\nGluons, 3 Weak Force Bosons, and a Photon that live on the links of\nthe lattice Spacetime; and 3 generations of 8 Fermion Particles and 8\nFermion AntiParticles that live on the vertices of the lattice\nSpacetime.\n\nIn terms of a 5-level grading of the E6 Lie algebra, that is, the\nGraded Lie Alagebra of type e7, we have\n\nE6(-14) =\n8-dim\n+ 16-dim\n+ R + so(1,7) + iR\n+ 16-dim\n+ 8-dim\nwith physical interpretation in the Lagrangian of the D4-D5-E6-E7-E8\nVoDou Physics Model as:\n\n8-dim of g(-2) plus R of g(0) plus 8-dim of g(2), an\n8-Complex-dimensional domain plus an R generator of Complex U(1)\nsymmetry, with an 8-real-dimensional Shilov boundary of the form S1 x\nS7, corresponds to an 8-dimensional spacetime base manifold over which\nthe Lagrangian integral is integrated;\nso(1,7) of g(0), the double cover of the Lorentz group over the\nOctonions, corresponds to the 28 generators of gauge bosons in the\ncurvature term of the Lagrangian integrand; and\n16-dim of g(-1) plus iR of g(0) plus 16-dim of g(1), a\n16-Complex-dimensional domain, the Complexified Octonion Plane\n(CxO)P2, plus an iR generator of Complex U(1) symmetry, with a Shilov\nboundary ( not entirely real, as the 16-Complex-dimensional domain is\nnot of tube type ) that may be regarded as being a bundle made up of a\nreal fibre S1 x S7 over a base space made up of S1 and CP4 ( note that\nthe CP4 has embedded S7 structure ), so that the real fibre S1 x S7\nrepresents 8 first-generation fermion particles in the Dirac spinor\nterm of the Lagrangian integrand, and an S1 x S7 in the base space\nrepresents 8 corresponding antiparticles.\n\n\nRelated Graded Lie Algebra structures give:\n\na Bohm Quantum Potential from 26-dimensional String Theory;\na 27-dimensional M-theory of timelike branes in the MacroSpace of the\nMany-Worlds; and\na 28-dimensional F-theory of spacelike branes in the MacroSpace of the\nMany-Worlds.\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Doug Sweetser <sweetser@alum.mit.edu> wrote in message news:<clqlfl$7a1$1@pcls4.std.com>...
> So Lubos, that brings me to a question for you. I would like to see one
> of these "pretty long" Lagrangians in 11 dimensions. Please try to
> label all the parts that go into it as I did for the standard model
> Lagrangian. I realize this is an ongoing area of research, so there is
> no consensus on which particular one to write out, I just would like to
> see one of the 11D Lagrange densities as part of my continuing
> education in string theory.
>
>
> doug
> quaternions.com
Here is Tony Smith's very well labeled Lagrangian for bosonic string
theory, I'm curious as to what you think of it:
the Integral over the Cl(1,7) vector 1+7=8-dimensional SpaceTime of
dd P' /\ * dd P + F /\ *F + S' D S + GF + GG
where
d is the 8-dim covariant derivative
P is the scalar field
F is the adjoint Spin(8) curvature
S' and S are half-spinor fermion spaces
D is the 8-dim Dirac operator
GF is the gauge-fixing term
GG is the ghost term,
plus a topological Pontrjagin term.
The Pontrjagin term represents Instantons in 8-dimensional spacetime
that is locally RP1 x S7. Since, after dimensional reduction of
spacetime from 8 to 4 dimensions, the Pontrjagin term goes into the
Spin(6) conformal gravity sector of the D4-D5-E6-E7-E8 VoDou physics
model, it does not go to the SU(3) color force sector. Therefore, the
SU(3) color force Sector has no \THETA-term and the D4-D5-E6-E7-E8
Vodou Physics model has no theoretical \THETA-CP problem.
After dimensional reduction to 4-dimensional spacetime, the S7 of RP1
x S7 is factored by the Hopf fibration S3 -> S7 -> S4 into
4-dimensional spacetime that is locally RP1 x S3, plus a CP2 part
related to 4-dimensional Internal Symmetry Space.
Reduction also produces, for each World of the Many-Worlds, a
4-dimensional lattice Spacetime with MacDowell-Mansouri Gravity, a
Higgs Mechanism, and a Complex Propagator Phase;
a 4-dimensional lattice Internal Symmetry Space with 8 Color Force
Gluons, 3 Weak Force Bosons, and a Photon that live on the links of
the lattice Spacetime; and 3 generations of 8 Fermion Particles and 8
Fermion AntiParticles that live on the vertices of the lattice
Spacetime.
In terms of a 5-level grading of the E6 Lie algebra, that is, the
Graded Lie Alagebra of type e7, we have
E6(-14) =8-dim+ 16-dim
+ R + so(1,7) + iR+ 16-dim+ 8-dim
with physical interpretation in the Lagrangian of the D4-D5-E6-E7-E8
VoDou Physics Model as:
8-dim of g(-2) plus R of g(0) plus 8-dim of g(2), an
8-Complex-dimensional domain plus an R generator of Complex U(1)
symmetry, with an 8-real-dimensional Shilov boundary of the form S1 x
S7, corresponds to an 8-dimensional spacetime base manifold over which
the Lagrangian integral is integrated;
so(1,7) of g(0), the double cover of the Lorentz group over the
Octonions, corresponds to the 28 generators of gauge bosons in the
curvature term of the Lagrangian integrand; and
16-dim of g(-1) plus iR of g(0) plus 16-dim of g(1), a
16-Complex-dimensional domain, the Complexified Octonion Plane
(CxO)P2, plus an iR generator of Complex U(1) symmetry, with a Shilov
boundary ( not entirely real, as the 16-Complex-dimensional domain is
not of tube type ) that may be regarded as being a bundle made up of a
real fibre S1 x S7 over a base space made up of S1 and CP4 ( note that
the CP4 has embedded S7 structure ), so that the real fibre S1 x S7
represents 8 first-generation fermion particles in the Dirac spinor
term of the Lagrangian integrand, and an S1 x S7 in the base space
represents 8 corresponding antiparticles.
Related Graded Lie Algebra structures give:
a Bohm Quantum Potential from 26-dimensional String Theory;
a 27-dimensional M-theory of timelike branes in the MacroSpace of the
Many-Worlds; and
a 28-dimensional F-theory of spacelike branes in the MacroSpace of the
Many-Worlds.
Doug Sweetser
Nov3-04, 10:59 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no,scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Hello backdoorstudent:\n\nSorry if I misquoted you.\n\nNature was using all the same laws of physics two billion years ago when\nonly single-celled organisms lived here, so she has historically been\nindifferent to us beings that did not exist :-) No matter our fate,\nshe will continue to work on grand scales.\n\nIt is common to quote Einstein, he is the Jimi Hendricks of physics :-)\nI tried to stay focused on equations and how they work. Do you know\nhow to:\n\n1. Derive the Maxwell equations from the classical Lagrange density?\n2. Derive Einstein\'s field equations from the Hilbert action?\n3. Derive the field equation of the standard model from its\nLagrangian?\n\nNo one was born knowing how to do these three. I learned how to do the\nfirst one in ~2001. I learned how to do the second one a few months\nago. The third one should be similar to the first, but I have not done\nit yet. If you have learned enough physics to do the calculation\nyourself, these are some of the most elegant uses of paper you will\nexperience in your life. The equations govern the behavior of photons,\nelectrons, and gravity throughout the entire Universe. Yes, much of\nphysics can and should be mundane, but the specific Lagrange densities\ncited reach across the Universe.\n\nI suspect the long, complicated Lagrange densities of string theory will\nnot have that same feel. Yet the pitch to the public does try to make\na connection. I want to see at least one example, kind of like calling\nthe bluff of a string theorist.\n\ndoug\nquaternions.com\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Hello backdoorstudent:
Sorry if I misquoted you.
Nature was using all the same laws of physics two billion years ago when
only single-celled organisms lived here, so she has historically been
indifferent to us beings that did not exist :-) No matter our fate,
she will continue to work on grand scales.
It is common to quote Einstein, he is the Jimi Hendricks of physics :-)
I tried to stay focused on equations and how they work. Do you know
how to:
1. Derive the Maxwell equations from the classical Lagrange density?
2. Derive Einstein's field equations from the Hilbert action?
3. Derive the field equation of the standard model from its
Lagrangian?
No one was born knowing how to do these three. I learned how to do the
first one in ~2001. I learned how to do the second one a few months
ago. The third one should be similar to the first, but I have not done
it yet. If you have learned enough physics to do the calculation
yourself, these are some of the most elegant uses of paper you will
experience in your life. The equations govern the behavior of photons,
electrons, and gravity throughout the entire Universe. Yes, much of
physics can and should be mundane, but the specific Lagrange densities
cited reach across the Universe.
I suspect the long, complicated Lagrange densities of string theory will
not have that same feel. Yet the pitch to the public does try to make
a connection. I want to see at least one example, kind of like calling
the bluff of a string theorist.
doug
quaternions.com
Spud
Nov3-04, 11:03 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no,location=no,scrollbars=yes,resizable=yes,status=no,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>backdoorstudent@yahoo.com (backdoorstudent) wrote in message news:<750f5e99.0410281615.67aeff9a@posting.google.com>...\n<snip>\n> > >> What\'s so "beautiful" or "elegant" about string theory?\n<snip>\n\n> If my opinion matters, -it doesn\'t, yet I cannot resist sharing it:)-\n> it is that the laws of the universe are completely indifferent to our\n> presumptions of beauty. Physicists love to romanticize about their\n> sense of beauty leading the way and repeatedly quote and make\n> reference to Einstein and his intellectual methods to support this\n> thesis. But the history of science reflects a much more mundane and\n> tortured endeavor based mostly on curiosity and common sense rather\n> than aesthetics. This is what leads me to feel that all this blather\n> about beauty and elegance is nothing more than pontification.\n\nRelevant:\nI have heard a Freemason use the word "Masonic" in relation to the\ndevelopment of the sciences and Brians book on string theory/s.\n\nSpud\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>backdoorstudent@yahoo.com (backdoorstudent) wrote in message news:<750f5e99.0410281615.67aeff9a@posting.google.co