View Full Version : new paper on causality
Charlie Stromeyer Jr.
Dec1-04, 12:54 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>Earlier, we talked some about string theory and causality, a subject\nwhich is not yet well understood so I\'ll now mention that there is a\nnew paper which makes some progress in the AdS_5 x S^5 context via the\nLLM description:\n\nhttp://arxiv.org/abs/hep-th/0411203\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>Earlier, we talked some about string theory and causality, a subject
which is not yet well understood so I'll now mention that there is a
new paper which makes some progress in the AdS_5 x S^5 context via the
LLM description:
http://arxiv.org/abs/http://www.arxiv.org/abs/hep-th/0411203
bjflanagan
Dec7-04, 02:24 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[Moderator\'s note: Followups should make sure to have some relation to\nstring theory. -usc]\n\n\nThis may be of interest:\n\n\'t Hooft: Determinism Beneath QM\n\nhttp://arxiv.org/abs/quant-ph/0212095\n\n_______________________________\n\nCont rary to common belief, it is not difficult to construct\ndeterministic models where stochastic behavior is correctly described\nby quantum mechanical amplitudes, in precise accordance with the\nCopenhagen-Bohr-Bohm doctrine. What is difficult however is to obtain a\nHamiltonian that is bounded from below, and whose ground state is a\nvacuum that exhibits complicated vacuum fluctuations, as in the real\nworld.\nBeneath Quantum Mechanics, there may be a deterministic theory with\n(local) information loss. This may lead to a sufficiently complex\nvacuum state, and to an apparent non-locality in the relation between\nthe deterministic ("ontological") states and the quantum states, of the\nkind needed to explain away the Bell inequalities.\n\n[...]\n\n8. Conclusions.\nOur view towards the quantum mechanical nature of our world can be\nsummarized as follows.\n· Nature\'s fundamental laws are defined at the Planck scale. At\nthat scale, all we have is bits of information.\n· A large fraction of this information gets lost very quickly, but it\nis being replenished by information entering from the boundaries.\n· A quantum state is defined to be an equivalence class of states\nwhich all have the same distant future. This definition is non-local and\nacausal, which implies that, if we would attempt to describe everything\nthat happens purely in conventional\nquantum mechanical terms, such as what is done in superstring theories,\nlocality and even causality will seem to be absent at the Planck scale.\nOnly in terms of a\ndeterministic theory this demand of internal logic can be met.\n· These equivalence classes are described by observables that we call\n\'beables\'. In quantum terminology, beables are a complete set of operators\nthat commute at all\ntimes, see Eq,(5.1). A beable describes what a Planckian observer would\nbe able to register about a system - information that did not get lost.\n\n_________________________________________ ______________________________________\nWeb page of SPS: http://schwinger.harvard.edu/~sps/\nPosted via: http://groups.google.com/groups?group=sci.physics.strings\n^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^\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>[Moderator's note: Followups should make sure to have some relation to
string theory. -usc]
This may be of interest:
't Hooft: Determinism Beneath QM
http://arxiv.org/abs/http://www.arxiv.org/abs/quant-ph/0212095
__{_____________________________}
Contrary to common belief, it is not difficult to construct
deterministic models where stochastic behavior is correctly described
by quantum mechanical amplitudes, in precise accordance with the
Copenhagen-Bohr-Bohm doctrine. What is difficult however is to obtain a
Hamiltonian that is bounded from below, and whose ground state is a
vacuum that exhibits complicated vacuum fluctuations, as in the real
world.
Beneath Quantum Mechanics, there may be a deterministic theory with
(local) information loss. This may lead to a sufficiently complex
vacuum state, and to an apparent non-locality in the relation between
the deterministic ("ontological") states and the quantum states, of the
kind needed to explain away the Bell inequalities.
[...]
8. Conclusions.
Our view towards the quantum mechanical nature of our world can be
summarized as follows.
· Nature's fundamental laws are defined at the Planck scale. At
that scale, all we have is bits of information.
· A large fraction of this information gets lost very quickly, but it
is being replenished by information entering from the boundaries.
· A quantum state is defined to be an equivalence class of states
which all have the same distant future. This definition is non-local and
acausal, which implies that, if we would attempt to describe everything
that happens purely in conventional
quantum mechanical terms, such as what is done in superstring theories,
locality and even causality will seem to be absent at the Planck scale.
Only in terms of a
deterministic theory this demand of internal logic can be met.
· These equivalence classes are described by observables that we call
'beables'. In quantum terminology, beables are a complete set of operators
that commute at all
times, see Eq,(5.1). A beable describes what a Planckian observer would
be able to register about a system - information that did not get lost.
__{_______________________________________________ ______________________________}
Web page of SPS: http://schwinger.harvard.edu/~sps/
Posted via: http://groups.google.com/groups?group=sci.physics.strings
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Urs Schreiber
Dec7-04, 06:30 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>"bjflanagan" <worda1@wordassociation1.net> schrieb im Newsbeitrag\nnews:1102366953.856160.78690-100000@f14g2000cwb.googlegroups.com...\n\n> This may be of interest:\n>\n> \'t Hooft: Determinism Beneath QM\n>\n> http://arxiv.org/abs/quant-ph/0212095\n\n[...]\n\n> · A quantum state is defined to be an equivalence class of states\n> which all have the same distant future. This definition is non-local and\n> acausal, which implies that, if we would attempt to describe everything\n> that happens purely in conventional\n> quantum mechanical terms, such as what is done in superstring theories,\n> locality and even causality will seem to be absent at the Planck scale.\n\n\nI once chatted about this with t\'Hooft over dinner. It is not precisely\nclear to me what he has in mind, but it seems to sort of fit very nicely in\nthe broad string theoretic picture. For instance t\'Hooft says that the fact\nthat only on-shell amplitudes are meaningful in string theory should be\ndirectly related to the fact that quantum mechanics only holds as kind of an\neffective theory on some holographic boundary. At least I belive that\'s what\nhe said. You can find more on that here:\n\nhttp://golem.ph.utexas.edu/string/archives/000400.html\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>"bjflanagan" <worda1@wordassociation1.net> schrieb im Newsbeitrag
news:1102366953.856160.78690-100000@f14g2000cwb.googlegroups.com...
> This may be of interest:
>
> 't Hooft: Determinism Beneath QM
>
> http://arxiv.org/abs/http://www.arxiv.org/abs/quant-ph/0212095
[...]
> · A quantum state is defined to be an equivalence class of states
> which all have the same distant future. This definition is non-local and
> acausal, which implies that, if we would attempt to describe everything
> that happens purely in conventional
> quantum mechanical terms, such as what is done in superstring theories,
> locality and even causality will seem to be absent at the Planck scale.
I once chatted about this with t'Hooft over dinner. It is not precisely
clear to me what he has in mind, but it seems to sort of fit very nicely in
the broad string theoretic picture. For instance t'Hooft says that the fact
that only on-shell amplitudes are meaningful in string theory should be
directly related to the fact that quantum mechanics only holds as kind of an
effective theory on some holographic boundary. At least I belive that's what
he said. You can find more on that here:
http://golem.ph.utexas.edu/string/archives/000400.html
<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>\nUrs Schreiber wrote:\n> "bjflanagan" <worda1@wordassociation1.net> schrieb im Newsbeitrag\n> news:1102366953.856160.78690-100000@f14g2000cwb.googlegroups.com...\n>\n> > This may be of interest:\n> >\n> > \'t Hooft: Determinism Beneath QM\n> >\n> > http://arxiv.org/abs/quant-ph/0212095\n>\n> [...]\n>\n> > · A quantum state is defined to be an equivalence class of states\n> > which all have the same distant future. This definition is\nnon-local and\n> > acausal, which implies that, if we would attempt to describe\neverything\n> > that happens purely in conventional\n> > quantum mechanical terms, such as what is done in superstring\ntheories,\n> > locality and even causality will seem to be absent at the Planck\nscale.\n>\n>\n> I once chatted about this with t\'Hooft over dinner. It is not\nprecisely\n> clear to me what he has in mind, but it seems to sort of fit very\nnicely in\n> the broad string theoretic picture. For instance t\'Hooft says that\nthe fact\n> that only on-shell amplitudes are meaningful in string theory should\nbe\n> directly related to the fact that quantum mechanics only holds as\nkind of an\n> effective theory on some holographic boundary. At least I belive\nthat\'s what\n> he said. You can find more on that here:\n>\n> http://golem.ph.utexas.edu/string/archives/000400.html\n\n\nIs it related to "The black hole final state" ?\nhttp://arxiv.org/abs/hep-th/0310281\n\n_______________________________________ ________________________________________\nWeb page of SPS: http://schwinger.harvard.edu/~sps/\nPosted via: http://groups.google.com/groups?group=sci.physics.strings\n^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^\n\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>Urs Schreiber wrote:
> "bjflanagan" <worda1@wordassociation1.net> schrieb im Newsbeitrag
> news:1102366953.856160.78690-100000@f14g2000cwb.googlegroups.com...
>
> > This may be of interest:
> >
> > 't Hooft: Determinism Beneath QM
> >
> > http://arxiv.org/abs/http://www.arxiv.org/abs/quant-ph/0212095
>
> [...]
>
> > · A quantum state is defined to be an equivalence class of states
> > which all have the same distant future. This definition is
non-local and
> > acausal, which implies that, if we would attempt to describe
everything
> > that happens purely in conventional
> > quantum mechanical terms, such as what is done in superstring
theories,
> > locality and even causality will seem to be absent at the Planck
scale.
>
>
> I once chatted about this with t'Hooft over dinner. It is not
precisely
> clear to me what he has in mind, but it seems to sort of fit very
nicely in
> the broad string theoretic picture. For instance t'Hooft says that
the fact
> that only on-shell amplitudes are meaningful in string theory should
be
> directly related to the fact that quantum mechanics only holds as
kind of an
> effective theory on some holographic boundary. At least I belive
that's what
> he said. You can find more on that here:
>
> http://golem.ph.utexas.edu/string/archives/000400.html
Is it related to "The black hole final state" ?
http://arxiv.org/abs/http://www.arxiv.org/abs/hep-th/0310281
__{_______________________________________________ ______________________________}
Web page of SPS: http://schwinger.harvard.edu/~sps/
Posted via: http://groups.google.com/groups?group=sci.physics.strings
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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