PDA

View Full Version : Spin networks and strings


Daniel
May5-04, 06:20 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>In 3 roads to QG, by Lee Smolin,\nhe seems to suggest that strings could, if resolved finely enough, be\na coherent symphony of string networks.\n\n[Moderator\'s note: you perhaps meant "spin networks".\nString networks are something that we also study, and\nthey are probably more interesting mathematically than\nthe spin networks. LM]\n\nWhat is the current string theory research on this subject matter?\nCould spin foam make up strings?\n\n[Moderator\'s note: Virtually every string theorist would agree\nthat there exists almost no evidence that the full string theory\ncan be described via spin networks and spin foams. Recent\npapers of Vafa and his collaborators try to change this\nsituation, and Vafa et al. have already found some extremely\nintriguing discrete physics (crystals) dual to a simplified\nversion of string theory, the so-called topological string\ntheory.\n\nBesides the efforts of Vafa, there also exists activity in the\nfield of loop quantum gravity to "include" string theory\n- activity associated with the names such as Lee Smolin,\nThomas Thiemann, Karl Pohlmeyer, and others. The majority\nof string theorists apparently has not found these proposals\nconvincing, interesting or likely, and therefore most of us don\'t\nwork on them seriously.\n\nThe unification of loop quantum gravity\nwith string theory is activity that squarely belongs to the camp\nof loop quantum gravity. This is the camp that apparently thinks\nthat everything goes, and any random conjecture or equation that\ncan be written on the paper or artificially constructed should be\nstudied as a theory of Nature. The other camp, the camp\ncontrolling this newsgroup, are the string theorists, and they\nbelieve that mathematical consistency as well as experimental\nfacts should be treated seriously, and they heavily constrain\nall these new hypotheses and regulate our imagination. LM]\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">&nbsp;&nbsp;View this Usenet post in original ASCII form </a></div><P></jabberwocky>In 3 roads to QG, by Lee Smolin,
he seems to suggest that strings could, if resolved finely enough, be
a coherent symphony of string networks.

[Moderator's note: you perhaps meant "spin networks".
String networks are something that we also study, and
they are probably more interesting mathematically than
the spin networks. LM]

What is the current string theory research on this subject matter?
Could spin foam make up strings?

[Moderator's note: Virtually every string theorist would agree
that there exists almost no evidence that the full string theory
can be described via spin networks and spin foams. Recent
papers of Vafa and his collaborators try to change this
situation, and Vafa et al. have already found some extremely
intriguing discrete physics (crystals) dual to a simplified
version of string theory, the so-called topological string
theory.

Besides the efforts of Vafa, there also exists activity in the
field of loop quantum gravity to "include" string theory
- activity associated with the names such as Lee Smolin,
Thomas Thiemann, Karl Pohlmeyer, and others. The majority
of string theorists apparently has not found these proposals
convincing, interesting or likely, and therefore most of us don't
work on them seriously.

The unification of loop quantum gravity
with string theory is activity that squarely belongs to the camp
of loop quantum gravity. This is the camp that apparently thinks
that everything goes, and any random conjecture or equation that
can be written on the paper or artificially constructed should be
studied as a theory of Nature. The other camp, the camp
controlling this newsgroup, are the string theorists, and they
believe that mathematical consistency as well as experimental
facts should be treated seriously, and they heavily constrain
all these new hypotheses and regulate our imagination. LM]

sol
May6-04, 07:43 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>Daniel &lt;ensabah6@yahoo.com&gt; wrote in message news:&lt;ba566c17.0405051324.437676c3-100000@posting.google.com&gt;...\n\n&gt; In 3 roads to QG, by Lee Smolin,\n&gt; he seems to suggest that strings could, if resolved finely enough, be\n&gt; a coherent symphony of string networks. ...\n\n[Moderator\'s note: The moderator believes that the text below is not really\nconnected with string theory or modern theoretical physics and that the\narticles mentioned below are irrelevant and not quite serious, but anyone\ncan make up her mind. LM]\n\n"A possible connection between the electromagnetic quantum vacuum and\ninertia was first published by Haisch, Rueda and Puthoff (1994). If\ncorrect, this would imply that mass may be an electromagnetic\nphenomenon and thus in principle subject to modification, with\npossible technological implications for propulsion. A multiyear\nNASA-funded study at the Lockheed Martin Advanced Technology Center\nfurther developed this concept, resulting in an independent\ntheoretical validation of the fundamental approach (Rueda and Haisch,\n1998ab). Distortion of the quantum vacuum in accelerated reference\nframes results in a force that appears to account for inertia. We have\nnow shown that the same effect occurs in a region of curved spacetime,\nthus elucidating the origin of the principle of equivalence (Rueda,\nHaisch and Tung, 2001). A further connection with general relativity\nhas been drawn by Nickisch and Mollere (2002): zero-point fluctuations\ngive rise to spacetime micro-curvature effects yielding a\ncomplementary perspective on the origin of inertia. Numerical\nsimulations of this effect demonstrate the manner in which a massless\nfundamental particle, e.g. an electron, acquires inertial properties;\nthis also shows the apparent origin of particle spin along lines\noriginally proposed by Schroedinger. Finally, we suggest that the\nheavier leptons (muon and tau) may be explainable as spatial-harmonic\nresonances of the (fundamental) electron. They would carry the same\noverall charge, but with the charge now having spatially lobed\nstructure, each lobe of which would respond to higher frequency\ncomponents of the electromagnetic quantum vacuum, thereby increasing\nthe inertia and thus manifesting a heavier mass."\n\nhttp://arxiv.org/abs/gr-qc/0209016\n\nWhat are your thoughts here Lubos?\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">&nbsp;&nbsp;View this Usenet post in original ASCII form </a></div><P></jabberwocky>Daniel <ensabah6@yahoo.com> wrote in message news:<ba566c17.0405051324.437676c3-100000@posting.google.com>...

> In 3 roads to QG, by Lee Smolin,
> he seems to suggest that strings could, if resolved finely enough, be
> a coherent symphony of string networks. ...

[Moderator's note: The moderator believes that the text below is not really
connected with string theory or modern theoretical physics and that the
articles mentioned below are irrelevant and not quite serious, but anyone
can make up her mind. LM]

"A possible connection between the electromagnetic quantum vacuum and
inertia was first published by Haisch, Rueda and Puthoff (1994). If
correct, this would imply that mass may be an electromagnetic
phenomenon and thus in principle subject to modification, with
possible technological implications for propulsion. A multiyear
NASA-funded study at the Lockheed Martin Advanced Technology Center
further developed this concept, resulting in an independent
theoretical validation of the fundamental approach (Rueda and Haisch,
1998ab). Distortion of the quantum vacuum in accelerated reference
frames results in a force that appears to account for inertia. We have
now shown that the same effect occurs in a region of curved spacetime,
thus elucidating the origin of the principle of equivalence (Rueda,
Haisch and Tung, 2001). A further connection with general relativity
has been drawn by Nickisch and Mollere (2002): zero-point fluctuations
give rise to spacetime micro-curvature effects yielding a
complementary perspective on the origin of inertia. Numerical
simulations of this effect demonstrate the manner in which a massless
fundamental particle, e.g. an electron, acquires inertial properties;
this also shows the apparent origin of particle spin along lines
originally proposed by Schroedinger. Finally, we suggest that the
heavier leptons (muon and \tau) may be explainable as spatial-harmonic
resonances of the (fundamental) electron. They would carry the same
overall charge, but with the charge now having spatially lobed
structure, each lobe of which would respond to higher frequency
components of the electromagnetic quantum vacuum, thereby increasing
the inertia and thus manifesting a heavier mass."

http://arxiv.org/abs/http://www.arxiv.org/abs/gr-qc/0209016

What are your thoughts here Lubos?

Daniel
May9-04, 07:03 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>yes, i mean spin networks, as stated in the subject.\nstring networks is a typo.\nby the way, have you heard of www.wikipedia.com?\n\n[Moderator\'s note: Yes, I think that it is a very good\npiece of work. LM]\n\nyour posts would benefit wikipedia enormously.\nyour posts for string theory could benefit wikipedia at\n\nhttp://en.wikipedia.org/wiki/String_theory\nhttp://en.wikipedia.org/wiki/Superstring_theory\nhttp://en.wikipedia.org/wiki/M-theory\n\nand your criticism of loop quantum gravity could benefit wikipedia at\n\nhttp://en.wikipedia.org/wiki/Loop_quantum_gravity\n\nalternatively, if i have your express permission, I can cut and paste\nyour posts and criticisms directly there.\n\n[Thank you very much for your nice words.\nSorry, I think that it would be better to improve these text\na lot before they are posted to such a relatively permanent place. LM]\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">&nbsp;&nbsp;View this Usenet post in original ASCII form </a></div><P></jabberwocky>yes, i mean spin networks, as stated in the subject.
string networks is a typo.
by the way, have you heard of www.wikipedia.com?

[Moderator's note: Yes, I think that it is a very good
piece of work. LM]

your posts would benefit wikipedia enormously.
your posts for string theory could benefit wikipedia at

http://en.wikipedia.org/wiki/String_theory
http://en.wikipedia.org/wiki/Superstring_theory
http://en.wikipedia.org/wiki/M-theory

and your criticism of loop quantum gravity could benefit wikipedia at

http://en.wikipedia.org/wiki/Loop_quantum_gravity

alternatively, if i have your express permission, I can cut and paste
your posts and criticisms directly there.

[Thank you very much for your nice words.
Sorry, I think that it would be better to improve these text
a lot before they are posted to such a relatively permanent place. LM]