View Full Version : Wave-function of Universe?
p.valletta
Apr9-04, 02:22 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>The Wave-function of the Universe is based on QM principles of probabilty\nand thus of observertional quantities. Quantum Tunneling is a good\nexperimental method of \'Wave-function\' analysis.\n\nIs it true that there is a corresponding \'Particle-function\', based on the\nsame variables? and could we use this to devise an experiment whereby a\n\'particle\' tunnels outside of the Universe revealing the\n\'Universe-wavefunction\'?\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>The Wave-function of the Universe is based on QM principles of probabilty
and thus of observertional quantities. Quantum Tunneling is a good
experimental method of 'Wave-function' analysis.
Is it true that there is a corresponding 'Particle-function', based on the
same variables? and could we use this to devise an experiment whereby a
'particle' tunnels outside of the Universe revealing the
'Universe-wavefunction'?
James Baugh
Apr15-04, 11:14 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>"p.valletta" <p.valletta@ntlworld.com> wrote in message news:<7Yndc.870\\$qe5.780@newsfe1-win>...\n> The Wave-function of the Universe is based on QM principles of probabilty\n> and thus of observertional quantities. Quantum Tunneling is a good\n> experimental method of \'Wave-function\' analysis.\n>\n> Is it true that there is a corresponding \'Particle-function\', based on the\n> same variables? and could we use this to devise an experiment whereby a\n> \'particle\' tunnels outside of the Universe revealing the\n> \'Universe-wavefunction\'?\n\nPardon Me,\nI began with a short note and it turned into a sermon,\nnot all of which may apply to your inquiry.\n********\n\n[First]\nBefore using such phrases as "The wave function of the Universe"\nfirst keep in mind what a "wave-funtion" means.\nIn QM a wave function is a distribution of probability\namplitudes over a range of possible obserables.\n(Usually but not always position observations, e.g.\nwe can have a wave function over momentum space.)\n\nIn other words it describes for example how likely we are to see\na particle pass through a pin-hole. The arguments (x,y,z,t)\ndescribe where the pin-hole i.e. measuring device "is" not where\nthe particle "is".\n\nIn (other) other words a wave function describes\n*What We Know* about the system w.r.t.\nthe probability of future observations.\nBefore you write down a wave function\nof "the universe" or any other posited\nsystem you first need to define what\n"the universe" means in terms of what\nmeasurements you can make.\n\n[Second]\nGiven we exist within "the universe" our knowledge of the universe\ncannot be complete (in the quantum sense of maximal). A measuring\ndevice cannot measure itself. (Thermodynamics is an integral part\nof the measuring process, you must have a heat sink to cool the\namplifier which amplifies the measurement signal. Measurement\nis by definition gain > 0 dB.)\nSo at best we should only define a Density Operator for the universe.\n\n[Third]\nHaving said this let me point out that "outside the universe"\nalso has no operational meaning. If we can reach it then it\ncan reach us in the sense of exchanging interactions and thus\nit is part of "The Universe" where one defines "The Universe" as\na limiting case of the largest system possible.\n\nQuantum theory does not posit extra dimensions or multiple universes.\n(Unless you need a plot device for a Science Fiction script.)\nIt simply gives us a more "stable" description of what we may\nobserve and how one act of observation can alter the outcome\nof future observations.\n\nToo many people have become confuse by reading\n"Many Worlds" re-interpretations of quatum theory\nwhich essentially tries to re-embed quantum theory\nwithin a larger classical framework.\nThe quantum language is by definition\na more general language than classical.\nIt simple relaxes assumptions about actions you may\neffect on a system (i.e. that all acts of\nobservation commute and thus have no effect on one another.)\n\nThe same sort of confusion arises when you play with relativized\nspace-time but try to stick it back into a context of absolute time.\nIn the example of the twin paradox the question of\n"Which twin is *really* older?" is just such a case.\nOnce you relativize you mustn\'t frame questions in\nterms of the old absolutes.\n\nQuantum theory relativizes the concept of physical state.\nHolding on to the same absolute assumptions that one has\nrelativized again leads to a paradox. In\nthis case the EPR paradox in the form of assumptions\nabout classical probabilities intrensically vested\nwith a particle when the probabilities of QM are\nintrensically non-local correlations between system\nand observer.\n\n"Collapsing wave functions" are exactly analogous to\n"collapsing average value of a Lotto ticket" when the drawing\nis held.\n\n[Fourth]\nI would qualify that the above doesn\'t preclude\nextra "hyperspace" dimensions. However assuming\nthere are we must ask if our "universe" is a "thin membrane" or\nif rather it extends into those extra dimensions completely.\nIt is one thing to posit extra dimensions\nand quite another to assume physical objects are already\nlocalized (i.e. thin) with respect to those dimensions.\nThis is the point of string theory. (although it too has\nserious conceptual problems.)\n\nOur three dimensional\nspatial picture may be just a cross section of a broader\npicture where an electron is a rope looping around\n4 dimensional hyper-space (ignoring time). But again\nthese are just mental pictures. The physics is in how\nthings behave and that is described mathematically\nwhere one can add as many dimensions as one wants.\nDon\'t confuse the mathematical model for the physics.\n\nToo many people do including\nquite a few PhD\'s in Physics.\n\nFinally with regard to "Tunneling". Tunneling\nis a phenomenon where classical theory predicts\nsomething is impossible while quantum theory\npredicts it is improbable but not impossible.\nThink of tunneling this way. I design an\nescape-proof prison. Suppose that I can prove\nmathmatically that . . .\n\n***provided the guards follow protocol***\n\nit is impossible for you to escape.\nBut in the "real world" the guards\nare only human and mistakes\nhave a certain probability of occuring.\nGiven this then I can only prove in the\nreal world that the probability of you\nescaping is very very small.\n\nThe classical potential describing\nsay the binding of an electron within\nan atom is just an idealized average description\nof the quantum electromagnetic field.\nThe actual electromagnetic field you\ncould view as "noisy" but its better just\nto say\n****The e-m potential only has meaning in QM\nas defined by the probabilistic behavior of a charged particle***\n\nThere is only a mystery when you try to\nimpose a classical picture on the behavior.\nAnytime you see the word "potential" remember\nit is an artifact used to describe how something\nelse behaves.\n\nCarry this back to descriptions of "The Universe"\n"The Universe" is not a four dimensional space-time\nmanifold with fields affixed to it. That is just a model.\nThe universe is a bunch of interacting processes.\nThe structure of their interaction we break down into\npieces which classically we describe as localized particles\nor continuous waves. Both are imperfect approximations and\nthe "quantum wave functions" are just a bit better.\nThe best description is simply to look at how different\nactions correlate. "Look for a click here after seeing a click there"\n(where what\'s clicking we classically describe as a particle detector.)\nThis is usually done with the operator algebras or Lie groups.\n(And usually done badly with infinite dimensional versions, hence\nthe problems with divergences when quantizing gravitation.)\n\n\nRegards\nJ. Baugh\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>"p.valletta" <p.valletta@ntlworld.com> wrote in message news:<7Yndc.870$qe5.780@newsfe1-win>...
> The Wave-function of the Universe is based on QM principles of probabilty
> and thus of observertional quantities. Quantum Tunneling is a good
> experimental method of 'Wave-function' analysis.
>
> Is it true that there is a corresponding 'Particle-function', based on the
> same variables? and could we use this to devise an experiment whereby a
> 'particle' tunnels outside of the Universe revealing the
> 'Universe-wavefunction'?
Pardon Me,
I began with a short note and it turned into a sermon,
not all of which may apply to your inquiry.
********
[First]
Before using such phrases as "The wave function of the Universe"
first keep in mind what a "wave-funtion" means.
In QM a wave function is a distribution of probability
amplitudes over a range of possible obserables.
(Usually but not always position observations, e.g.
we can have a wave function over momentum space.)
In other words it describes for example how likely we are to see
a particle pass through a pin-hole. The arguments (x,y,z,t)
describe where the pin-hole i.e. measuring device "is" not where
the particle "is".
In (other) other words a wave function describes
*What We Know* about the system w.r.t.
the probability of future observations.
Before you write down a wave function
of "the universe" or any other posited
system you first need to define what
"the universe" means in terms of what
measurements you can make.
[Second]
Given we exist within "the universe" our knowledge of the universe
cannot be complete (in the quantum sense of maximal). A measuring
device cannot measure itself. (Thermodynamics is an integral part
of the measuring process, you must have a heat sink to cool the
amplifier which amplifies the measurement signal. Measurement
is by definition gain > dB.)
So at best we should only define a Density Operator for the universe.
[Third]
Having said this let me point out that "outside the universe"
also has no operational meaning. If we can reach it then it
can reach us in the sense of exchanging interactions and thus
it is part of "The Universe" where one defines "The Universe" as
a limiting case of the largest system possible.
Quantum theory does not posit extra dimensions or multiple universes.
(Unless you need a plot device for a Science Fiction script.)
It simply gives us a more "stable" description of what we may
observe and how one act of observation can alter the outcome
of future observations.
Too many people have become confuse by reading
"Many Worlds" re-interpretations of quatum theory
which essentially tries to re-embed quantum theory
within a larger classical framework.
The quantum language is by definition
a more general language than classical.
It simple relaxes assumptions about actions you may
effect on a system (i.e. that all acts of
observation commute and thus have no effect on one another.)
The same sort of confusion arises when you play with relativized
space-time but try to stick it back into a context of absolute time.
In the example of the twin paradox the question of
"Which twin is *really* older?" is just such a case.
Once you relativize you mustn't frame questions in
terms of the old absolutes.
Quantum theory relativizes the concept of physical state.
Holding on to the same absolute assumptions that one has
relativized again leads to a paradox. In
this case the EPR paradox in the form of assumptions
about classical probabilities intrensically vested
with a particle when the probabilities of QM are
intrensically non-local correlations between system
and observer.
"Collapsing wave functions" are exactly analogous to
"collapsing average value of a Lotto ticket" when the drawing
is held.
[Fourth]
I would qualify that the above doesn't preclude
extra "hyperspace" dimensions. However assuming
there are we must ask if our "universe" is a "thin membrane" or
if rather it extends into those extra dimensions completely.
It is one thing to posit extra dimensions
and quite another to assume physical objects are already
localized (i.e. thin) with respect to those dimensions.
This is the point of string theory. (although it too has
serious conceptual problems.)
Our three dimensional
spatial picture may be just a cross section of a broader
picture where an electron is a rope looping around
4 dimensional hyper-space (ignoring time). But again
these are just mental pictures. The physics is in how
things behave and that is described mathematically
where one can add as many dimensions as one wants.
Don't confuse the mathematical model for the physics.
Too many people do including
quite a few PhD's in Physics.
Finally with regard to "Tunneling". Tunneling
is a phenomenon where classical theory predicts
something is impossible while quantum theory
predicts it is improbable but not impossible.
Think of tunneling this way. I design an
escape-proof prison. Suppose that I can prove
mathmatically that . . .
***provided the guards follow protocol***
it is impossible for you to escape.
But in the "real world" the guards
are only human and mistakes
have a certain probability of occuring.
Given this then I can only prove in the
real world that the probability of you
escaping is very very small.
The classical potential describing
say the binding of an electron within
an atom is just an idealized average description
of the quantum electromagnetic field.
The actual electromagnetic field you
could view as "noisy" but its better just
to say
****The e-m potential only has meaning in QM
as defined by the probabilistic behavior of a charged particle***
There is only a mystery when you try to
impose a classical picture on the behavior.
Anytime you see the word "potential" remember
it is an artifact used to describe how something
else behaves.
Carry this back to descriptions of "The Universe"
"The Universe" is not a four dimensional space-time
manifold with fields affixed to it. That is just a model.
The universe is a bunch of interacting processes.
The structure of their interaction we break down into
pieces which classically we describe as localized particles
or continuous waves. Both are imperfect approximations and
the "quantum wave functions" are just a bit better.
The best description is simply to look at how different
actions correlate. "Look for a click here after seeing a click there"
(where what's clicking we classically describe as a particle detector.)
This is usually done with the operator algebras or Lie groups.
(And usually done badly with infinite dimensional versions, hence
the problems with divergences when quantizing gravitation.)
Regards
J. Baugh
<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"p.valletta" <p.valletta@ntlworld.com> wrote in message news:<7Yndc.870\\$qe5.780@newsfe1-win>...\n\n> The Wave-function of the Universe is based on QM principles of\n>probabilty and thus of observertional quantities.\n\nAs I understand it, the "wavefunction of the universe" is just\na wavefunction over a set X, just as wavefunctions are in\nordinary QM, except that instead of being "a one particle\nposition configuration space", it\'s a "many particle position\nconfiguration space" or, in other words(view) a field\nconfigurations space. Now, acording to some people, this\ncan be seen as the configuration space which consists of all\npossible geometries for space. In other words, all these views,\nwhether they coincide or not, are examples of what\npeople mean when they use the word "wavefunction of the\nuniverse" .\n\n>Quantum\n>Tunneling is a good experimental method of \'Wave-function\'\n>analysis.\n\nTunneling, is a property of a whole scenario, that\ninvolves a wavefunction and a potential. It doesn\'t\nreally "analyze" the wavefunction. But If you mean\nthat it serves to show a funky property that a\nwavefunction-slash-potential can have, I\'ll agree with you.\n\n> Is it true that there is a corresponding \'Particle-function\',\nbased on the same variables? and could we use this to devise\nan experiment whereby a \'particle\' tunnels outside of the\nUniverse revealing the \'Universe-wavefunction\'?\n\nAgain just because an "initial wavefunction---potential scenario"\ndisplays tunneling, it does not mean that--the fact that\nthere\'s tunneling "reveals the wavefunction". This statement\nis void of sense.\n\nFurthermore the wavefunction of the universe whether or\nnot it can be written as a "wavefn-potential scenario"\nand whether or not it "displays tunneling" , will not\npredict anything "tunneling out of the universe". In fact\nthe ways in which this quoted statement is senseless can\nteach you a lot. Try to think about it.\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>"p.valletta" <p.valletta@ntlworld.com> wrote in message news:<7Yndc.870$qe5.780@newsfe1-win>...
> The Wave-function of the Universe is based on QM principles of
>probabilty and thus of observertional quantities.
As I understand it, the "wavefunction of the universe" is just
a wavefunction over a set X, just as wavefunctions are in
ordinary QM, except that instead of being "a one particle
position configuration space", it's a "many particle position
configuration space" or, in other words(view) a field
configurations space. Now, acording to some people, this
can be seen as the configuration space which consists of all
possible geometries for space. In other words, all these views,
whether they coincide or not, are examples of what
people mean when they use the word "wavefunction of the
universe" .
>Quantum
>Tunneling is a good experimental method of 'Wave-function'
>analysis.
Tunneling, is a property of a whole scenario, that
involves a wavefunction and a potential. It doesn't
really "analyze" the wavefunction. But If you mean
that it serves to show a funky property that a
wavefunction-slash-potential can have, I'll agree with you.
> Is it true that there is a corresponding 'Particle-function',
based on the same variables? and could we use this to devise
an experiment whereby a 'particle' tunnels outside of the
Universe revealing the 'Universe-wavefunction'?
Again just because an "initial wavefunction---potential scenario"
displays tunneling, it does not mean that--the fact that
there's tunneling "reveals the wavefunction". This statement
is void of sense.
Furthermore the wavefunction of the universe whether or
not it can be written as a "wavefn-potential scenario"
and whether or not it "displays tunneling" , will not
predict anything "tunneling out of the universe". In fact
the ways in which this quoted statement is senseless can
teach you a lot. Try to think about it.
Urs Schreiber
Apr19-04, 02:10 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>"p.valletta" <p.valletta@ntlworld.com> wrote in message news:<7Yndc.870\\$qe5.780@newsfe1-win>...\n\n> The Wave-function of the Universe is [...]\n\nIn order to understand what people mean when they refer to the "wave\nfunction of the universe" read an introductory review paper like\n\nD Wiltshire, An Introduction to Quantum Cosmology,\ngr-qc/0101003\nhttp://arxiv.org/abs/gr-qc/0101003 .\n\n\nBasically the idea is that if everything in the world is described by\na quantum theory, then any state in this "Theory of Everything" would\nbe a "wave function of the universe". This would be supposed to\ncontain the full information about the state of the universe\ncompletely analogous to how any state in quantum physics encodes the\nfull information about any given physical system.\n\nBut we don\'t know the full TOE yet and cannot yet write down full\n"wave functions of the universe". That\'s why you will usually see the\nterm "wave function of the universe" in the context of what is called\n"quantum cosmology". In this approach people try to reduce the\ndynamics of the (visible) universe roughly by just a handful of\nparameters, like the size factor of the universe as well as the\nhomogeneous modes of certain spacetime fields. Such a "reduction"\nleaves you with a quantum _mechanical_ (= finitely many degrees of\nfreedom) theory, which you can try to study. Every state in this\nquantum cosmology would then also be called a "wave function of the\nuniverse" in the literature, even though it is really only (hoped to)\ncontain an infinitesimal amount of the information encoded in the true\nthing.\n\nOn the other hand, in recent years there has been increasing evidence\nthat the full degrees of freedom of what might be M-theory is\ndescribed by a "quantum cosmology" with configuration space being that\nof the group of the Kac-Moody algebra E10. Indeed, one can check that\nto 30th order (in some appropriate expansion) this model does\nreproduce all the degrees of freedom of 11 diemsnional supergravity,\nwhich is, by definition, the low-energy limit of the the conjectured\n"M-theory". And one can give furthermore evidence that to lowest order\nthe "wave functions of the universe" of this E10 theory do reproduce\nthe correct mass spectrum of certain D-brane configurations.\n\nThat\'s why there is currently the pretty well motivated conjecture\nthat the "wave function of the universe" might be a wave function on\nthe immense group manifold of E10. (Actually, this isn\'t well defined\n(yet), but every finite "truncation" of it is, in an appropriate\nsense.)\n\nYou can find the references to this "bosonic M-theory is the Laplace\nequation of E10"-conjecture in the thread\n\nSupergravity Cosmological Billiards and the BIG group\nhttp://groups.google.com/groups?selm=Pine.LNX.4.31.0404071937500.4467-100000%40feynman.harvard.edu\n\non sci.physics.strings.\n\n(But let me emphasize that every beginner who hasn\'t seen any quantum\ncosmology papers before should start with the review that I mentioned\nabove. Then read the very nicely written review\n\nDamour & Henneuax & Nicolai\nCosmological Billiards,\nhep-th/0212256\n\nand then see how to move on. )\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>"p.valletta" <p.valletta@ntlworld.com> wrote in message news:<7Yndc.870$qe5.780@newsfe1-win>...
> The Wave-function of the Universe is [...]
In order to understand what people mean when they refer to the "wave
function of the universe" read an introductory review paper like
D Wiltshire, An Introduction to Quantum Cosmology,
http://www.arxiv.org/abs/gr-qc/0101003
http://arxiv.org/abs/http://www.arxiv.org/abs/gr-qc/0101003 .
Basically the idea is that if everything in the world is described by
a quantum theory, then any state in this "Theory of Everything" would
be a "wave function of the universe". This would be supposed to
contain the full information about the state of the universe
completely analogous to how any state in quantum physics encodes the
full information about any given physical system.
But we don't know the full TOE yet and cannot yet write down full
"wave functions of the universe". That's why you will usually see the
term "wave function of the universe" in the context of what is called
"quantum cosmology". In this approach people try to reduce the
dynamics of the (visible) universe roughly by just a handful of
parameters, like the size factor of the universe as well as the
homogeneous modes of certain spacetime fields. Such a "reduction"
leaves you with a quantum _mechanical_ (= finitely many degrees of
freedom) theory, which you can try to study. Every state in this
quantum cosmology would then also be called a "wave function of the
universe" in the literature, even though it is really only (hoped to)
contain an infinitesimal amount of the information encoded in the true
thing.
On the other hand, in recent years there has been increasing evidence
that the full degrees of freedom of what might be M-theory is
described by a "quantum cosmology" with configuration space being that
of the group of the Kac-Moody algebra E10. Indeed, one can check that
to 30th order (in some appropriate expansion) this model does
reproduce all the degrees of freedom of 11 diemsnional supergravity,
which is, by definition, the low-energy limit of the the conjectured
"M-theory". And one can give furthermore evidence that to lowest order
the "wave functions of the universe" of this E10 theory do reproduce
the correct mass spectrum of certain D-brane configurations.
That's why there is currently the pretty well motivated conjecture
that the "wave function of the universe" might be a wave function on
the immense group manifold of E10. (Actually, this isn't well defined
(yet), but every finite "truncation" of it is, in an appropriate
sense.)
You can find the references to this "bosonic M-theory is the Laplace
equation of E10"-conjecture in the thread
Supergravity Cosmological Billiards and the BIG group
http://groups.google.com/groups?selm=Pine.LNX.4.31.0404071937500.4467-100000%40feynman.harvard.edu
on sci.physics.strings.
(But let me emphasize that every beginner who hasn't seen any quantum
cosmology papers before should start with the review that I mentioned
above. Then read the very nicely written review
Damour & Henneuax & Nicolai
Cosmological Billiards,
http://www.arxiv.org/abs/hep-th/0212256
and then see how to move on. )
James Baugh
Apr28-04, 02:47 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>***Disclaimer: I tend to preach and am preaching "at" the readers\nof this post though it is a reply to a specific submission.\nPlease don\'t take my comments as judgment or attack on the prior\npost.]\n\n(from last post...)\n\n>...\n> Basically the idea is that if everything in the world is described by\n> a quantum theory, then any state in this "Theory of Everything" would\n> be a "wave function of the universe". This would be supposed to\n> contain the full information about the state of the universe\n> completely analogous to how any state in quantum physics encodes the\n> full information about any given....\n\n\nQuantum theories don\'t describe "things" directly and\n"full information" begs a question of completeness.\nIn truth classical theories really don\'t describe "things" either.\nRather they too describe actions and observables. Where the "thing"\ndescriptions come in is at the level of a *Model*.\n\nQuantum theory *extends* "complete" to a more general concept of\n"maximal". This is a distinction about how information may be\ngathered.\n\n"Quantizing" adds to the theory by subtracting from the assumption\nthat\n"maximal set of compatable observables"\nand\n"all possible observables"\nare equivalent.\n\nEquating "maximal" with "all" is equivalent to assuming there is\na unique maximally specific model\n(of mathematical objects with mathematical properties equatated to\nobservables).\nNo one (ontological) model can encapsulate all the variables of a\nquantum\ntheory since "properties of mathematical objects"\nare determined by deduction/calculation and not by empirical\nobservation.\n\nThis is not to say quantum theory doesn\'t use "reality models". The\n"wave-functions" and "state vectors" model statistical assertions\nabout what may happen.\nProperly speaking the "vectors" are not even the main elements of this\n"information model". They are defining elements of one dimensional\nsub-spaces\nof the Hilbert space. This space defines a lattice of sub-spaces\nwhich *models* the logical lattice of predicates about a system.\n"X is a subspace of Y" models the logical inference:\n"if we observe x we can infer y".\nUsing spaces allows more than absolute inference so that topologically\nwe can relate:\n"X is *close to* a subspace of Y"\nto\n"if we observe x then we can infer that y is *likely*."\nThis logical model can be utilized for both classical and quantum\ntheory.\n\nThe relationship between "how close" and "how likely" defines\nthe type of theory.\n\nThe confusion of these logical models with classical "reality models"\nleads to confusion about interpetation.\n\nTwo examples are the Einstein-Podolsky-Rosen (EPR)\nparadox and (the ever so silly)\nEverett\'s Many Worlds "interpretation" of QM.\n\nBell\'s inequality in the EPR experiment is itself a\ncalculation from a most general set of classical models\n(probability distributions over an arbitrary state space.)\nIts violation in QM simply states that QM is not a classical\ntheory.\n\nLikewise "Many Worlds" is not an interpretation. It is a\nquasi-classical re-interpretation in terms of a (poorly defined)\nclassical ontological model.\n\n\nConfusions about the distinction between "model" and "theory"\nhas led to the current fad of "string theories" and "super-<blank>\ntheories"\nwhich have polluted our major theoretical research institutions.\nThese are not properly theories but rather mathematical constructs\nwhich hope to one day become models for theories and which reuse\nmany terms from physics.\n\n\nNow getting back to the concept of "Tunneling". "Tunneling" events\nare quantum transitions which are forbidden by a corresponding\nclassical theory.\n\nThere are reverse phenomenon such as particle interference.\nClassical electrons with fixed initial momentum can scatter\nthrough pin-holes or slits and reach any of the points on a\nphotographic film (some regions more often than others.)\n\nQuantum electrons have a different distribution of scattering\nthrough the same openings and there will be some positions\non the film where none of the electrons ever land.\n\nOne could say the classical particles "tunnel" to\nthose points on the film except that what we see in the lab is only\nthe quantum case. So such a "classical tunneling phenomenon" can\'t\nbe demonstrated.\n\n\nRegards,\nJ. Baugh\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>***Disclaimer: I tend to preach and am preaching "at" the readers
of this post though it is a reply to a specific submission.
Please don't take my comments as judgment or attack on the prior
post.]
(from last post...)
>...
> Basically the idea is that if everything in the world is described by
> a quantum theory, then any state in this "Theory of Everything" would
> be a "wave function of the universe". This would be supposed to
> contain the full information about the state of the universe
> completely analogous to how any state in quantum physics encodes the
> full information about any given....
Quantum theories don't describe "things" directly and
"full information" begs a question of completeness.
In truth classical theories really don't describe "things" either.
Rather they too describe actions and observables. Where the "thing"
descriptions come in is at the level of a *Model*.
Quantum theory *extends* "complete" to a more general concept of
"maximal". This is a distinction about how information may be
gathered.
"Quantizing" adds to the theory by subtracting from the assumption
that
"maximal set of compatable observables"
and
"all possible observables"
are equivalent.
Equating "maximal" with "all" is equivalent to assuming there is
a unique maximally specific model
(of mathematical objects with mathematical properties equatated to
observables).
No one (ontological) model can encapsulate all the variables of a
quantum
theory since "properties of mathematical objects"
are determined by deduction/calculation and not by empirical
observation.
This is not to say quantum theory doesn't use "reality models". The
"wave-functions" and "state vectors" model statistical assertions
about what may happen.
Properly speaking the "vectors" are not even the main elements of this
"information model". They are defining elements of one dimensional
sub-spaces
of the Hilbert space. This space defines a lattice of sub-spaces
which *models* the logical lattice of predicates about a system.
"X is a subspace of Y" models the logical inference:
"if we observe x we can infer y".
Using spaces allows more than absolute inference so that topologically
we can relate:
"X is *close to* a subspace of Y"
to
"if we observe x then we can infer that y is *likely*."
This logical model can be utilized for both classical and quantum
theory.
The relationship between "how close" and "how likely" defines
the type of theory.
The confusion of these logical models with classical "reality models"
leads to confusion about interpetation.
Two examples are the Einstein-Podolsky-Rosen (EPR)
paradox and (the ever so silly)
Everett's Many Worlds "interpretation" of QM.
Bell's inequality in the EPR experiment is itself a
calculation from a most general set of classical models
(probability distributions over an arbitrary state space.)
Its violation in QM simply states that QM is not a classical
theory.
Likewise "Many Worlds" is not an interpretation. It is a
quasi-classical re-interpretation in terms of a (poorly defined)
classical ontological model.
Confusions about the distinction between "model" and "theory"
has led to the current fad of "string theories" and "super-<blank>
theories"
which have polluted our major theoretical research institutions.
These are not properly theories but rather mathematical constructs
which hope to one day become models for theories and which reuse
many terms from physics.
Now getting back to the concept of "Tunneling". "Tunneling" events
are quantum transitions which are forbidden by a corresponding
classical theory.
There are reverse phenomenon such as particle interference.
Classical electrons with fixed initial momentum can scatter
through pin-holes or slits and reach any of the points on a
photographic film (some regions more often than others.)
Quantum electrons have a different distribution of scattering
through the same openings and there will be some positions
on the film where none of the electrons ever land.
One could say the classical particles "tunnel" to
those points on the film except that what we see in the lab is only
the quantum case. So such a "classical tunneling phenomenon" can't
be demonstrated.
Regards,
J. Baugh
vBulletin® v3.7.6, Copyright ©2000-2009, Jelsoft Enterprises Ltd.