View Full Version : Does decoherence solve the measurement problem? (was:How probable
Arnold Neumaier
Aug27-04, 10:05 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>\nJoe Rongen wrote:\n>\n> It maybe of interest to note here what Brian Greene in his over\n> simplified book "The Fabric of the Cosmos" wrote, [...] on page 212,\n> that he is not\n> "yet fully convinced" that "decohence (histories)" exist but others\n> claim that they have developed decoherence into a complete frame-\n> work that solves the measurement problem.\n\nMany physicist nowadays think that decoherence provides a fully\nsatisfying answer to the measurement problem. But this is an illusion.\n\nDecoherence is the decay of off-diagonal contributions\nin a density matrix (written in a preferred basis),\nwhen information dissipates into unobservable degrees of\nfreedom in the environment of a system. In particular,\nit reduces a pure state to a _mixture_ of eigenstates.\n(This is enough to induce classical features in many large quantum\nsystems, characterized by a lack of interference terms.)\n\nOn the other hand, the \'collapse of the wave function\'\nselects _one_ of the eigenstates as the observed one.\nThis \'\'problem of definite outcomes\'\'\nis not explained by decoherence and is still a riddle.\nSee the excellent survey article in quant-ph/0312059.\n\nThe champions of the decoherence approach are (not always\nbut at least sometimes) quite careful to\ndelineate what decoherence can do and what it leaves open.\nIf the big crowd has a cruder point of view, it means nothing but\nlack of familiarity with the details.\n\n(From my theoretical physics FAQ at\nhttp://www.mat.univie.ac.at/~neum/physics-faq.txt)\n\n\nArnold Neumaier\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>Joe Rongen wrote:
>
> It maybe of interest to note here what Brian Greene in his over
> simplified book "The Fabric of the Cosmos" wrote, [...] on page 212,
> that he is not
> "yet fully convinced" that "decohence (histories)" exist but others
> claim that they have developed decoherence into a complete frame-
> work that solves the measurement problem.
Many physicist nowadays think that decoherence provides a fully
satisfying answer to the measurement problem. But this is an illusion.
Decoherence is the decay of off-diagonal contributions
in a density matrix (written in a preferred basis),
when information dissipates into unobservable degrees of
freedom in the environment of a system. In particular,
it reduces a pure state to a _mixture_ of eigenstates.
(This is enough to induce classical features in many large quantum
systems, characterized by a lack of interference terms.)
On the other hand, the 'collapse of the wave function'
selects _one_ of the eigenstates as the observed one.
This ''problem of definite outcomes''
is not explained by decoherence and is still a riddle.
See the excellent survey article in http://www.arxiv.org/abs/quant-ph/0312059.
The champions of the decoherence approach are (not always
but at least sometimes) quite careful to
delineate what decoherence can do and what it leaves open.
If the big crowd has a cruder point of view, it means nothing but
lack of familiarity with the details.
(From my theoretical physics FAQ at
http://www.mat.univie.ac.at/~neum/physics-faq.txt)
Arnold Neumaier
Joe Rongen
Aug28-04, 04:28 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>"Arnold Neumaier" <Arnold.Neumaier@univie.ac.at>\nwrote in message news:412F4C06.5000505@univie.ac.at...\n\n[snip]\n\n> On the other hand, the \'collapse of the wave function\'\n> selects _one_ of the eigenstates as the observed one.\n> This \'\'problem of definite outcomes\'\'\n> is not explained by decoherence and is still a riddle.\n\nWhile reading Henry Krips, "The metaphysics of quantum theory"\nI came across the following \'basic\' wave function contradiction,\nany suggestions?\n\n"Consider a single electron fired towards a photographic\nplate some distance away. Suppose the electron is literally\na wave-coincident with the electron\'s state-function. Then\nit will spread out by the time it reaches the screen, Indeed\nit can be made to spread as far as we like by putting the plate\nfar enough away. But the electron registers at the plate\nessentially as a single point. Therefore in the small interval of\ntime it takes to register on the plate it contracts from as far away\nas we like to essential a point. This phenomena is called \'the\ncollapse of the wave-packet\'. It requires that the leading edge\nof the wave travels with a speed which can be made as large\nas we like simply by arranging for the plate to be far enough\naway from the point of origin of the electron. But this (so the\nargument goes) contradicts the law of special relativity that\nno speed can exceed that of light, at least not for systems\nwith non-zero mass. So the electron cannot literally be a wave,\nat least not in the sense of having its mass literally spread out\nto coincide with the boundaries of the wave."\n\nRegards Joe\n\n\n---\nOutgoing mail is certified Virus Free.\nChecked by AVG anti-virus system (http://www.grisoft.com).\nVersion: 6.0.744 / Virus Database: 496 - Release Date: 8/24/04\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>"Arnold Neumaier" <Arnold.Neumaier@univie.ac.at>
wrote in message news:412F4C06.5000505@univie.ac.at...
[snip]
> On the other hand, the 'collapse of the wave function'
> selects _one_ of the eigenstates as the observed one.
> This ''problem of definite outcomes''
> is not explained by decoherence and is still a riddle.
While reading Henry Krips, "The metaphysics of quantum theory"
I came across the following 'basic' wave function contradiction,
any suggestions?
"Consider a single electron fired towards a photographic
plate some distance away. Suppose the electron is literally
a wave-coincident with the electron's state-function. Then
it will spread out by the time it reaches the screen, Indeed
it can be made to spread as far as we like by putting the plate
far enough away. But the electron registers at the plate
essentially as a single point. Therefore in the small interval of
time it takes to register on the plate it contracts from as far away
as we like to essential a point. This phenomena is called 'the
collapse of the wave-packet'. It requires that the leading edge
of the wave travels with a speed which can be made as large
as we like simply by arranging for the plate to be far enough
away from the point of origin of the electron. But this (so the
argument goes) contradicts the law of special relativity that
no speed can exceed that of light, at least not for systems
with non-zero mass. So the electron cannot literally be a wave,
at least not in the sense of having its mass literally spread out
to coincide with the boundaries of the wave."
Regards Joe
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6..744 / Virus Database: 496 - Release Date: 8/24/04
Ralph E. Frost
Aug28-04, 04:30 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>"Arnold Neumaier" <Arnold.Neumaier@univie.ac.at> wrote in message\nnews:412F4C06.5000505@univie.ac.at...\n>\ n> Joe Rongen wrote:\n> >\n> > It maybe of interest to note here what Brian Greene in his over\n> > simplified book "The Fabric of the Cosmos" wrote, [...] on page 212,\n> > that he is not\n> > "yet fully convinced" that "decohence (histories)" exist but others\n> > claim that they have developed decoherence into a complete frame-\n> > work that solves the measurement problem.\n>\n> Many physicist nowadays think that decoherence provides a fully\n> satisfying answer to the measurement problem. But this is an illusion.\n>\n> Decoherence is the decay of off-diagonal contributions\n> in a density matrix (written in a preferred basis),\n> when information dissipates into unobservable degrees of\n> freedom in the environment of a system. In particular,\n> it reduces a pure state to a _mixture_ of eigenstates.\n> (This is enough to induce classical features in many large quantum\n> systems, characterized by a lack of interference terms.)\n>\n> On the other hand, the \'collapse of the wave function\'\n> selects _one_ of the eigenstates as the observed one.\n> This \'\'problem of definite outcomes\'\'\n> is not explained by decoherence and is still a riddle.\n> See the excellent survey article in quant-ph/0312059.\n>\n> The champions of the decoherence approach are (not always\n> but at least sometimes) quite careful to\n> delineate what decoherence can do and what it leaves open.\n> If the big crowd has a cruder point of view, it means nothing but\n> lack of familiarity with the details.\n>\n> (From my theoretical physics FAQ at\n> http://www.mat.univie.ac.at/~neum/physics-faq.txt)\n>\n\nI\'m wondering if you can help me to understand, or at least grow in my\nappreciation of what you refer to.\n\nIs it fair to say that ~(collapse of the wavefunction, decohering\ndisappations and pure states resolving to mixed state) are all --How does\none say it?-- internal or ~quantum or quantum-like processes? (Internal to\nthe persistance ~classical stuff.)\n\nIf yes, then what about the ~external interactions? I guess those would be\nlike the influences of enfolding magnetic field, gravitation, etc?\n\nAre those just ignored?\n\n\n--\nRalph Frost\nImagine consciousness as\na single internal analog language\nmade of ordered water...\nand its variants.\nhttp://flep.refrost.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>"Arnold Neumaier" <Arnold.Neumaier@univie.ac.at> wrote in message
news:412F4C06.5000505@univie.ac.at...
>
> Joe Rongen wrote:
> >
> > It maybe of interest to note here what Brian Greene in his over
> > simplified book "The Fabric of the Cosmos" wrote, [...] on page 212,
> > that he is not
> > "yet fully convinced" that "decohence (histories)" exist but others
> > claim that they have developed decoherence into a complete frame-
> > work that solves the measurement problem.
>
> Many physicist nowadays think that decoherence provides a fully
> satisfying answer to the measurement problem. But this is an illusion.
>
> Decoherence is the decay of off-diagonal contributions
> in a density matrix (written in a preferred basis),
> when information dissipates into unobservable degrees of
> freedom in the environment of a system. In particular,
> it reduces a pure state to a _mixture_ of eigenstates.
> (This is enough to induce classical features in many large quantum
> systems, characterized by a lack of interference terms.)
>
> On the other hand, the 'collapse of the wave function'
> selects _one_ of the eigenstates as the observed one.
> This ''problem of definite outcomes''
> is not explained by decoherence and is still a riddle.
> See the excellent survey article in http://www.arxiv.org/abs/quant-ph/0312059.
>
> The champions of the decoherence approach are (not always
> but at least sometimes) quite careful to
> delineate what decoherence can do and what it leaves open.
> If the big crowd has a cruder point of view, it means nothing but
> lack of familiarity with the details.
>
> (From my theoretical physics FAQ at
> http://www.mat.univie.ac.at/~neum/physics-faq.txt)
>
I'm wondering if you can help me to understand, or at least grow in my
appreciation of what you refer to.
Is it fair to say that ~(collapse of the wavefunction, decohering
disappations and pure states resolving to mixed state) are all --How does
one say it?-- internal or ~quantum or quantum-like processes? (Internal to
the persistance ~classical stuff.)
If yes, then what about the ~external interactions? I guess those would be
like the influences of enfolding magnetic field, gravitation, etc?
Are those just ignored?
--
Ralph Frost
Imagine consciousness as
a single internal analog language
made of ordered water...
and its variants.
http://flep.refrost.com
John T Lowry
Aug29-04, 01:39 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 most coherent (not a pun) point of view, IMO, is that the wave funct\nion is descriptive of an ensemble of similarly prepared electrons, NOT\nof this individual electron. My suggestion is that your next read be\ninto the AAPT collection "Foundations of QM Since the Bell Inequalities"\nedited by L.E. Ballentine, or his equally persuasive and very thorough\ntextbook, "Quantum Mechanics: A Modern Development." You\'ll like them.\n\nI\'ve been reading a bit about decoherence and it DOES seem pretty\nconvincing\nas a way out of the "collapse" problem. On the other hand the Gottfried\net al\nidea of "essentially" irreversible interference terms seems pretty\nconvincing too.\nNot that those two are in fatal conflict.\n\nJohn Lowry\nFlight Physics\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 most coherent (not a pun) point of view, IMO, is that the wave funct
ion is descriptive of an ensemble of similarly prepared electrons, NOT
of this individual electron. My suggestion is that your next read be
into the AAPT collection "Foundations of QM Since the Bell Inequalities"
edited by L.E. Ballentine, or his equally persuasive and very thorough
textbook, "Quantum Mechanics: A Modern Development." You'll like them.
I've been reading a bit about decoherence and it DOES seem pretty
convincing
as a way out of the "collapse" problem. On the other hand the Gottfried
et al
idea of "essentially" irreversible interference terms seems pretty
convincing too.
Not that those two are in fatal conflict.
John Lowry
Flight Physics
FrediFizzx
Aug29-04, 01:39 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>"Joe Rongen" <joe@alpha.to> wrote in message\nnews:009101c48c5c\\$10ed8d20\\$2723fea9@r esearch...\n| "Arnold Neumaier" <Arnold.Neumaier@univie.ac.at>\n| wrote in message news:412F4C06.5000505@univie.ac.at...\n|\n| [snip]\n|\n| > On the other hand, the \'collapse of the wave function\'\n| > selects _one_ of the eigenstates as the observed one.\n| > This \'\'problem of definite outcomes\'\'\n| > is not explained by decoherence and is still a riddle.\n|\n| While reading Henry Krips, "The metaphysics of quantum theory"\n| I came across the following \'basic\' wave function contradiction,\n| any suggestions?\n|\n| "Consider a single electron fired towards a photographic\n| plate some distance away. Suppose the electron is literally\n| a wave-coincident with the electron\'s state-function. Then\n| it will spread out by the time it reaches the screen, Indeed\n| it can be made to spread as far as we like by putting the plate\n| far enough away. But the electron registers at the plate\n| essentially as a single point. Therefore in the small interval of\n| time it takes to register on the plate it contracts from as far away\n| as we like to essential a point. This phenomena is called \'the\n| collapse of the wave-packet\'. It requires that the leading edge\n| of the wave travels with a speed which can be made as large\n| as we like simply by arranging for the plate to be far enough\n| away from the point of origin of the electron. But this (so the\n| argument goes) contradicts the law of special relativity that\n| no speed can exceed that of light, at least not for systems\n| with non-zero mass. So the electron cannot literally be a wave,\n| at least not in the sense of having its mass literally spread out\n| to coincide with the boundaries of the wave."\n\nHow do we know that the "wave" in fact "collapsed" with a zero or shorter\ntime interval than that required by SR? Am I missing something here?\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>"Joe Rongen" <joe@\alpha.to> wrote in message
news:009101c48c5c$10ed8d20$2723fea9@research...
| "Arnold Neumaier" <Arnold.Neumaier@univie.ac.at>
| wrote in message news:412F4C06.5000505@univie.ac.at...
|
| [snip]
|
| > On the other hand, the 'collapse of the wave function'
| > selects _one_ of the eigenstates as the observed one.
| > This ''problem of definite outcomes''
| > is not explained by decoherence and is still a riddle.
|
| While reading Henry Krips, "The metaphysics of quantum theory"
| I came across the following 'basic' wave function contradiction,
| any suggestions?
|
| "Consider a single electron fired towards a photographic
| plate some distance away. Suppose the electron is literally
| a wave-coincident with the electron's state-function. Then
| it will spread out by the time it reaches the screen, Indeed
| it can be made to spread as far as we like by putting the plate
| far enough away. But the electron registers at the plate
| essentially as a single point. Therefore in the small interval of
| time it takes to register on the plate it contracts from as far away
| as we like to essential a point. This phenomena is called 'the
| collapse of the wave-packet'. It requires that the leading edge
| of the wave travels with a speed which can be made as large
| as we like simply by arranging for the plate to be far enough
| away from the point of origin of the electron. But this (so the
| argument goes) contradicts the law of special relativity that
| no speed can exceed that of light, at least not for systems
| with non-zero mass. So the electron cannot literally be a wave,
| at least not in the sense of having its mass literally spread out
| to coincide with the boundaries of the wave."
How do we know that the "wave" in fact "collapsed" with a zero or shorter
time interval than that required by SR? Am I missing something here?
FrediFizzx
Greysky
Aug29-04, 01:39 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>"Joe Rongen" <joe@alpha.to> wrote in message\nnews:009101c48c5c\\$10ed8d20\\$2723fea9@r esearch...\n> "Arnold Neumaier" <Arnold.Neumaier@univie.ac.at>\n> wrote in message news:412F4C06.5000505@univie.ac.at...\n>\n> [snip]\n>\n> > On the other hand, the \'collapse of the wave function\'\n> > selects _one_ of the eigenstates as the observed one.\n> > This \'\'problem of definite outcomes\'\'\n> > is not explained by decoherence and is still a riddle.\n>\n> While reading Henry Krips, "The metaphysics of quantum theory"\n> I came across the following \'basic\' wave function contradiction,\n> any suggestions?\n>\n> "Consider a single electron fired towards a photographic\n> plate some distance away. Suppose the electron is literally\n> a wave-coincident with the electron\'s state-function. Then\n> it will spread out by the time it reaches the screen, Indeed\n> it can be made to spread as far as we like by putting the plate\n> far enough away. But the electron registers at the plate\n> essentially as a single point. Therefore in the small interval of\n> time it takes to register on the plate it contracts from as far away\n> as we like to essential a point. This phenomena is called \'the\n> collapse of the wave-packet\'. It requires that the leading edge\n> of the wave travels with a speed which can be made as large\n> as we like simply by arranging for the plate to be far enough\n> away from the point of origin of the electron. But this (so the\n> argument goes) contradicts the law of special relativity that\n> no speed can exceed that of light, at least not for systems\n> with non-zero mass. So the electron cannot literally be a wave,\n> at least not in the sense of having its mass literally spread out\n> to coincide with the boundaries of the wave."\n>\n> Regards Joe\n>\nMay I point out that the electron wave is an Imaginary entity. There are no\nspecial rules limiting how fast an imaginary wave may collapse. The event we\ncan measure is real in the sense that it contains information about the\npre - collapsed matter wave while it is in this imaginary state... what this\ntells me is that the universe does not distinguish between what is \'real\'\nand what is \'imaginary\' as long as we make no measurements. The rules of\nrelativity only apply to an event that was detected... but that is like\nputting the cart before the horse, and guessing there is a horse somewhere\nsimply because we can see the cart. Quantum mechanics tells us to avoid a\nparadox in logic by not getting the message and the medium confused.\n\nGreysky\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>"Joe Rongen" <joe@\alpha.to> wrote in message
news:009101c48c5c$10ed8d20$2723fea9@research...
> "Arnold Neumaier" <Arnold.Neumaier@univie.ac.at>
> wrote in message news:412F4C06.5000505@univie.ac.at...
>
> [snip]
>
> > On the other hand, the 'collapse of the wave function'
> > selects _one_ of the eigenstates as the observed one.
> > This ''problem of definite outcomes''
> > is not explained by decoherence and is still a riddle.
>
> While reading Henry Krips, "The metaphysics of quantum theory"
> I came across the following 'basic' wave function contradiction,
> any suggestions?
>
> "Consider a single electron fired towards a photographic
> plate some distance away. Suppose the electron is literally
> a wave-coincident with the electron's state-function. Then
> it will spread out by the time it reaches the screen, Indeed
> it can be made to spread as far as we like by putting the plate
> far enough away. But the electron registers at the plate
> essentially as a single point. Therefore in the small interval of
> time it takes to register on the plate it contracts from as far away
> as we like to essential a point. This phenomena is called 'the
> collapse of the wave-packet'. It requires that the leading edge
> of the wave travels with a speed which can be made as large
> as we like simply by arranging for the plate to be far enough
> away from the point of origin of the electron. But this (so the
> argument goes) contradicts the law of special relativity that
> no speed can exceed that of light, at least not for systems
> with non-zero mass. So the electron cannot literally be a wave,
> at least not in the sense of having its mass literally spread out
> to coincide with the boundaries of the wave."
>
> Regards Joe
>
May I point out that the electron wave is an Imaginary entity. There are no
special rules limiting how fast an imaginary wave may collapse. The event we
can measure is real in the sense that it contains information about the
pre - collapsed matter wave while it is in this imaginary state... what this
tells me is that the universe does not distinguish between what is 'real'
and what is 'imaginary' as long as we make no measurements. The rules of
relativity only apply to an event that was detected... but that is like
putting the cart before the horse, and guessing there is a horse somewhere
simply because we can see the cart. Quantum mechanics tells us to avoid a
paradox in logic by not getting the message and the medium confused.
Greysky
Arnold Neumaier
Aug29-04, 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>John T Lowry wrote:\n> The most coherent (not a pun) point of view, IMO, is that the wave funct\n> ion is descriptive of an ensemble of similarly prepared electrons, NOT\n> of this individual electron. My suggestion is that your next read be\n> into the AAPT collection "Foundations of QM Since the Bell Inequalities"\n> edited by L.E. Ballentine, or his equally persuasive and very thorough\n> textbook, "Quantum Mechanics: A Modern Development." You\'ll like them.\n\nIts main linitation is that it does not apply to systems that are so large\nthat they are unique. Today no one disputes that the sun is governed by\nquantum mechanics. But one cannot apply statistical reasoning to the sun\nas a whole.\n\nThus Ballentine\'s interpretation cannot be the last word on the matter.\n\n\nArnold Neumaier\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>John T Lowry wrote:
> The most coherent (not a pun) point of view, IMO, is that the wave funct
> ion is descriptive of an ensemble of similarly prepared electrons, NOT
> of this individual electron. My suggestion is that your next read be
> into the AAPT collection "Foundations of QM Since the Bell Inequalities"
> edited by L.E. Ballentine, or his equally persuasive and very thorough
> textbook, "Quantum Mechanics: A Modern Development." You'll like them.
Its main linitation is that it does not apply to systems that are so large
that they are unique. Today no one disputes that the sun is governed by
quantum mechanics. But one cannot apply statistical reasoning to the sun
as a whole.
Thus Ballentine's interpretation cannot be the last word on the matter.
Arnold Neumaier
Arnold Neumaier
Aug29-04, 12:55 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>Joe Rongen wrote:\n> "Arnold Neumaier" <Arnold.Neumaier@univie.ac.at>\n> wrote in message news:412F4C06.5000505@univie.ac.at...\n>\n> [snip]\n>\n>\n>>On the other hand, the \'collapse of the wave function\'\n>>selects _one_ of the eigenstates as the observed one.\n>>This \'\'problem of definite outcomes\'\'\n>>is not explained by decoherence and is still a riddle.\n>\n>\n> While reading Henry Krips, "The metaphysics of quantum theory"\n> I came across the following \'basic\' wave function contradiction,\n> any suggestions?\n>\n> "Consider a single electron fired towards a photographic\n> plate some distance away. Suppose the electron is literally\n> a wave-coincident with the electron\'s state-function. Then\n> it will spread out by the time it reaches the screen, Indeed\n> it can be made to spread as far as we like by putting the plate\n> far enough away. But the electron registers at the plate\n> essentially as a single point. Therefore in the small interval of\n> time it takes to register on the plate it contracts from as far away\n> as we like to essential a point.\n\nIn my view, this description is a valid interpretation. Thinking\nthis way allows one to visualize many otherwise incompehensible\nhappenings in the quantum domain. The chemists do it all the time\nwhen visualizing molecules in terms of orbitals, and with great success.\n\n\n> This phenomena is called \'the\n> collapse of the wave-packet\'. It requires that the leading edge\n> of the wave travels with a speed which can be made as large\n> as we like simply by arranging for the plate to be far enough\n> away from the point of origin of the electron. But this (so the\n> argument goes) contradicts the law of special relativity that\n> no speed can exceed that of light, at least not for systems\n> with non-zero mass.\n\nSpecial relativity is only about the observational consequences\nof theory. Since most of the wave function of an individual particle\nis unobservable, there is no contradiction.\n\nIt is like the nonlocality in tests of Bell\'s inequalities.\nNonlocality is unavoidable in QM, but the observable consequences\nrespect special relativity.\n\n\nArnold Neumaier\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>Joe Rongen wrote:
> "Arnold Neumaier" <Arnold.Neumaier@univie.ac.at>
> wrote in message news:412F4C06.5000505@univie.ac.at...
>
> [snip]
>
>
>>On the other hand, the 'collapse of the wave function'
>>selects _one_ of the eigenstates as the observed one.
>>This ''problem of definite outcomes''
>>is not explained by decoherence and is still a riddle.
>
>
> While reading Henry Krips, "The metaphysics of quantum theory"
> I came across the following 'basic' wave function contradiction,
> any suggestions?
>
> "Consider a single electron fired towards a photographic
> plate some distance away. Suppose the electron is literally
> a wave-coincident with the electron's state-function. Then
> it will spread out by the time it reaches the screen, Indeed
> it can be made to spread as far as we like by putting the plate
> far enough away. But the electron registers at the plate
> essentially as a single point. Therefore in the small interval of
> time it takes to register on the plate it contracts from as far away
> as we like to essential a point.
In my view, this description is a valid interpretation. Thinking
this way allows one to visualize many otherwise incompehensible
happenings in the quantum domain. The chemists do it all the time
when visualizing molecules in terms of orbitals, and with great success.
> This phenomena is called 'the
> collapse of the wave-packet'. It requires that the leading edge
> of the wave travels with a speed which can be made as large
> as we like simply by arranging for the plate to be far enough
> away from the point of origin of the electron. But this (so the
> argument goes) contradicts the law of special relativity that
> no speed can exceed that of light, at least not for systems
> with non-zero mass.
Special relativity is only about the observational consequences
of theory. Since most of the wave function of an individual particle
is unobservable, there is no contradiction.
It is like the nonlocality in tests of Bell's inequalities.
Nonlocality is unavoidable in QM, but the observable consequences
respect special relativity.
Arnold Neumaier
Joe Rongen
Aug30-04, 03:57 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"Arnold Neumaier" <Arnold.Neumaier@univie.ac.at> wrote in\nmessage news:413189B2.9000406@univie.ac.at...\n> Joe Rongen wrote:\n> > "Arnold Neumaier" <Arnold.Neumaier@univie.ac.at>\n> > wrote in message news:412F4C06.5000505@univie.ac.at...\n[snip]\n\n> Special relativity is only about the observational consequences\n> of theory. Since most of the wave function of an individual particle\n> is unobservable, there is no contradiction.\n\nSorry, I do not think that you have a valid point.\n\nHave a look at any television. There you see many individually\nselected electrons in a clearly observable manner and yes, SP is\ntaking in account during the CRT and electronics engineering process.\n\n\nRegards Joe\n\n\n---\nOutgoing mail is certified Virus Free.\nChecked by AVG anti-virus system (http://www.grisoft.com).\nVersion: 6.0.744 / Virus Database: 496 - Release Date: 8/24/04\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>"Arnold Neumaier" <Arnold.Neumaier@univie.ac.at> wrote in
message news:413189B2.9000406@univie.ac.at...
> Joe Rongen wrote:
> > "Arnold Neumaier" <Arnold.Neumaier@univie.ac.at>
> > wrote in message news:412F4C06.5000505@univie.ac.at...
[snip]
> Special relativity is only about the observational consequences
> of theory. Since most of the wave function of an individual particle
> is unobservable, there is no contradiction.
Sorry, I do not think that you have a valid point.
Have a look at any television. There you see many individually
selected electrons in a clearly observable manner and yes, SP is
taking in account during the CRT and electronics engineering process.
Regards Joe
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6..744 / Virus Database: 496 - Release Date: 8/24/04
Franz Heymann
Aug30-04, 03:57 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"Joe Rongen" <joe@alpha.to> wrote in message\nnews:009101c48c5c\\$10ed8d20\\$2723fea9@r esearch...\n> "Arnold Neumaier" <Arnold.Neumaier@univie.ac.at>\n> wrote in message news:412F4C06.5000505@univie.ac.at...\n>\n> [snip]\n>\n> > On the other hand, the \'collapse of the wave function\'\n> > selects _one_ of the eigenstates as the observed one.\n> > This \'\'problem of definite outcomes\'\'\n> > is not explained by decoherence and is still a riddle.\n>\n> While reading Henry Krips, "The metaphysics of quantum theory"\n> I came across the following \'basic\' wave function contradiction,\n> any suggestions?\n>\n> "Consider a single electron fired towards a photographic\n> plate some distance away. Suppose the electron is literally\n> a wave-coincident with the electron\'s state-function.\n\nThat is an entirely incorrect supposition. The radial extent of the\ncharge distribution of the electron has been measured. It is\nconsistent with being a point object, to withinn a resolution of\n2.8*10^-19 metres.\nThe actual sitution is that the electron is, as best we know, a point\nparticle whose dynamics are governed not by Newtonian mechanics but\nby the evolution of its wave function.\n\n[snip]\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>"Joe Rongen" <joe@\alpha.to> wrote in message
news:009101c48c5c$10ed8d20$2723fea9@research...
> "Arnold Neumaier" <Arnold.Neumaier@univie.ac.at>
> wrote in message news:412F4C06.5000505@univie.ac.at...
>
> [snip]
>
> > On the other hand, the 'collapse of the wave function'
> > selects _one_ of the eigenstates as the observed one.
> > This ''problem of definite outcomes''
> > is not explained by decoherence and is still a riddle.
>
> While reading Henry Krips, "The metaphysics of quantum theory"
> I came across the following 'basic' wave function contradiction,
> any suggestions?
>
> "Consider a single electron fired towards a photographic
> plate some distance away. Suppose the electron is literally
> a wave-coincident with the electron's state-function.
That is an entirely incorrect supposition. The radial extent of the
charge distribution of the electron has been measured. It is
consistent with being a point object, to withinn a resolution of
2.8*10^-19 metres.
The actual sitution is that the electron is, as best we know, a point
particle whose dynamics are governed not by Newtonian mechanics but
by the evolution of its wave function.
[snip]
Franz
Arnold Neumaier
Aug30-04, 03:57 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\nRalph E. Frost wrote:\n> "Arnold Neumaier" <Arnold.Neumaier@univie.ac.at> wrote in message\n> news:412F4C06.5000505@univie.ac.at...\n>>Decoheren ce is the decay of off-diagonal contributions\n>>in a density matrix (written in a preferred basis),\n>>when information dissipates into unobservable degrees of\n>>freedom in the environment of a system. In particular,\n>>it reduces a pure state to a _mixture_ of eigenstates.\n>>(This is enough to induce classical features in many large quantum\n>>systems, characterized by a lack of interference terms.)\n>>\n>>On the other hand, the \'collapse of the wave function\'\n>>selects _one_ of the eigenstates as the observed one.\n>>This \'\'problem of definite outcomes\'\'\n>>is not explained by decoherence and is still a riddle.\n>>See the excellent survey article in quant-ph/0312059.\n>\n> I\'m wondering if you can help me to understand, or at least grow in my\n> appreciation of what you refer to.\n>\n> Is it fair to say that ~(collapse of the wavefunction, decohering\n> disappations and pure states resolving to mixed state) are all --How does\n> one say it?-- internal or ~quantum or quantum-like processes? (Internal to\n> the persistance ~classical stuff.)\n>\n> If yes, then what about the ~external interactions? I guess those would be\n> like the influences of enfolding magnetic field, gravitation, etc?\n\nQuantum mechanics appears to be universal. If there are relevant external\nforces, one can account for them by extending the system. Thus a\nconsistent theory of internal dynamics also handles the external issues.\n\nIn actual practice, external forces are just mean field approximations\nto the interactions with the dominant matter outside the system of interest.\n\n\nArnold Neumaier\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>Ralph E. Frost wrote:
> "Arnold Neumaier" <Arnold.Neumaier@univie.ac.at> wrote in message
> news:412F4C06.5000505@univie.ac.at...
>>Decoherence is the decay of off-diagonal contributions
>>in a density matrix (written in a preferred basis),
>>when information dissipates into unobservable degrees of
>>freedom in the environment of a system. In particular,
>>it reduces a pure state to a _mixture_ of eigenstates.
>>(This is enough to induce classical features in many large quantum
>>systems, characterized by a lack of interference terms.)
>>
>>On the other hand, the 'collapse of the wave function'
>>selects _one_ of the eigenstates as the observed one.
>>This ''problem of definite outcomes''
>>is not explained by decoherence and is still a riddle.
>>See the excellent survey article in http://www.arxiv.org/abs/quant-ph/0312059.
>
> I'm wondering if you can help me to understand, or at least grow in my
> appreciation of what you refer to.
>
> Is it fair to say that ~(collapse of the wavefunction, decohering
> disappations and pure states resolving to mixed state) are all --How does
> one say it?-- internal or ~quantum or quantum-like processes? (Internal to
> the persistance ~classical stuff.)
>
> If yes, then what about the ~external interactions? I guess those would be
> like the influences of enfolding magnetic field, gravitation, etc?
Quantum mechanics appears to be universal. If there are relevant external
forces, one can account for them by extending the system. Thus a
consistent theory of internal dynamics also handles the external issues.
In actual practice, external forces are just mean field approximations
to the interactions with the dominant matter outside the system of interest.
Arnold Neumaier
Arnold Neumaier
Aug30-04, 03:57 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\nFrediFizzx wrote:\n> "Joe Rongen" <joe@alpha.to> wrote in message\n> news:009101c48c5c\\$10ed8d20\\$2723fea9@research.. .\n> | "Consider a single electron fired towards a photographic\n> | plate some distance away. Suppose the electron is literally\n> | a wave-coincident with the electron\'s state-function. Then\n> | it will spread out by the time it reaches the screen, Indeed\n> | it can be made to spread as far as we like by putting the plate\n> | far enough away. But the electron registers at the plate\n> | essentially as a single point. Therefore in the small interval of\n> | time it takes to register on the plate it contracts from as far away\n> | as we like to essential a point. This phenomena is called \'the\n> | collapse of the wave-packet\'. It requires that the leading edge\n> | of the wave travels with a speed which can be made as large\n> | as we like simply by arranging for the plate to be far enough\n> | away from the point of origin of the electron. But this (so the\n> | argument goes) contradicts the law of special relativity that\n> | no speed can exceed that of light, at least not for systems\n> | with non-zero mass. So the electron cannot literally be a wave,\n> | at least not in the sense of having its mass literally spread out\n> | to coincide with the boundaries of the wave."\n>\n> How do we know that the "wave" in fact "collapsed" with a zero or shorter\n> time interval than that required by SR? Am I missing something here?\n\nThe collapse is usually modelled as instantaneous.\nNevertheless, real collapse should take some time.\n\nOn the other hand, wave functions are usually _infinitely_ extended,\nso a finite collapse time would not eliminate the paradox _if_ the\nwave function of a single particle were observable. But since it isn\'t,\nthere is no problem, since measurable information does _not_ spread\ninstantaneously, as discussed many times in the context of experiments\non nonlocality.\n\n\nArnold Neumaier\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>FrediFizzx wrote:
> "Joe Rongen" <joe@\alpha.to> wrote in message
> news:009101c48c5c$10ed8d20$2723fea9@research...
> | "Consider a single electron fired towards a photographic
> | plate some distance away. Suppose the electron is literally
> | a wave-coincident with the electron's state-function. Then
> | it will spread out by the time it reaches the screen, Indeed
> | it can be made to spread as far as we like by putting the plate
> | far enough away. But the electron registers at the plate
> | essentially as a single point. Therefore in the small interval of
> | time it takes to register on the plate it contracts from as far away
> | as we like to essential a point. This phenomena is called 'the
> | collapse of the wave-packet'. It requires that the leading edge
> | of the wave travels with a speed which can be made as large
> | as we like simply by arranging for the plate to be far enough
> | away from the point of origin of the electron. But this (so the
> | argument goes) contradicts the law of special relativity that
> | no speed can exceed that of light, at least not for systems
> | with non-zero mass. So the electron cannot literally be a wave,
> | at least not in the sense of having its mass literally spread out
> | to coincide with the boundaries of the wave."
>
> How do we know that the "wave" in fact "collapsed" with a zero or shorter
> time interval than that required by SR? Am I missing something here?
The collapse is usually modelled as instantaneous.
Nevertheless, real collapse should take some time.
On the other hand, wave functions are usually _infinitely_ extended,
so a finite collapse time would not eliminate the paradox _if_ the
wave function of a single particle were observable. But since it isn't,
there is no problem, since measurable information does _not_ spread
instantaneously, as discussed many times in the context of experiments
on nonlocality.
Arnold Neumaier
Arnold Neumaier
Aug30-04, 04:28 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\nJoe Rongen wrote:\n> "Arnold Neumaier" <Arnold.Neumaier@univie.ac.at> wrote in\n> message news:413189B2.9000406@univie.ac.at...\n>\n>>Joe Rongen wrote:\n>>\n>>>"Arnold Neumaier" <Arnold.Neumaier@univie.ac.at>\n>>>wrote in message news:412F4C06.5000505@univie.ac.at...\n>\n>>Specia l relativity is only about the observational consequences\n>>of theory. Since most of the wave function of an individual particle\n>>is unobservable, there is no contradiction.\n>\n> Sorry, I do not think that you have a valid point.\n>\n> Have a look at any television. There you see many individually\n> selected electrons in a clearly observable manner and yes, SP is\n> taking in account during the CRT and electronics engineering process.\n\nNote that I didn\'t claim that individual particles are unobservable,\nbut only that most of the information in their wave function is\nunobservable. On a TV set, you observe just 3 degrees of freedom of\nthe electrons, while the wave function sits in a function space\nwith infinitely many degrees of freedom. Thus you observe only a\ntiny little bit about the wave function, as claimed.\n\nTo get a reasonable approximation of the state of a particle,\none needs a large ensemble of identically prepared particles (to make\nsure one has the same state) and then subject them to different kinds\nof measurements from which one can reconstruct the state by quantum\ntomography.\n\n\nArnold Neumaier\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>Joe Rongen wrote:
> "Arnold Neumaier" <Arnold.Neumaier@univie.ac.at> wrote in
> message news:413189B2.9000406@univie.ac.at...
>
>>Joe Rongen wrote:
>>
>>>"Arnold Neumaier" <Arnold.Neumaier@univie.ac.at>
>>>wrote in message news:412F4C06.5000505@univie.ac.at...
>
>>Special relativity is only about the observational consequences
>>of theory. Since most of the wave function of an individual particle
>>is unobservable, there is no contradiction.
>
> Sorry, I do not think that you have a valid point.
>
> Have a look at any television. There you see many individually
> selected electrons in a clearly observable manner and yes, SP is
> taking in account during the CRT and electronics engineering process.
Note that I didn't claim that individual particles are unobservable,
but only that most of the information in their wave function is
unobservable. On a TV set, you observe just 3 degrees of freedom of
the electrons, while the wave function sits in a function space
with infinitely many degrees of freedom. Thus you observe only a
tiny little bit about the wave function, as claimed.
To get a reasonable approximation of the state of a particle,
one needs a large ensemble of identically prepared particles (to make
sure one has the same state) and then subject them to different kinds
of measurements from which one can reconstruct the state by quantum
tomography.
Arnold Neumaier
Joe Rongen
Aug30-04, 02:24 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>"Greysky" <greyskynospam@sbcglobal.net> wrote in\nmessage news:7A4Yc.9068\\$QJ3.4187@newssvr21.news.prodigy. com...\n[snip]\n\n> May I point out that the electron wave is an Imaginary entity. There\n> are no special rules limiting how fast an imaginary wave may collapse.\n> The event we can measure is real in the sense that it contains information\n> about the pre - collapsed matter wave while it is in this imaginary\n> state... what this tells me is that the universe does not distinguish\n> between what is \'real\' and what is \'imaginary\' as long as we make no\n> measurements.\n\nThank you. One question, should one substitute the\nword "imaginary" in the above with "indeterminate"?\n\nRegards Joe\n\n\n---\nOutgoing mail is certified Virus Free.\nChecked by AVG anti-virus system (http://www.grisoft.com).\nVersion: 6.0.744 / Virus Database: 496 - Release Date: 8/24/04\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>"Greysky" <greyskynospam@sbcglobal.net> wrote in
message news:7A4Yc.9068$QJ3.4187@newssvr21.news.prodigy.co m...
[snip]
> May I point out that the electron wave is an Imaginary entity. There
> are no special rules limiting how fast an imaginary wave may collapse.
> The event we can measure is real in the sense that it contains information
> about the pre - collapsed matter wave while it is in this imaginary
> state... what this tells me is that the universe does not distinguish
> between what is 'real' and what is 'imaginary' as long as we make no
> measurements.
Thank you. One question, should one substitute the
word "imaginary" in the above with "indeterminate"?
Regards Joe
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6..744 / Virus Database: 496 - Release Date: 8/24/04
Arnold Neumaier
Aug30-04, 02:25 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>Franz Heymann wrote:\n\n> The radial extent of the\n> charge distribution of the electron has been measured. It is\n> consistent with being a point object, to withinn a resolution of\n> 2.8*10^-19 metres.\n> The actual sitution is that the electron is, as best we know, a point\n> particle\n\nNo. Only the bare electron is a point particle. The physical electron is\nnot, since it has a nontrivial form factor, which can be measured\nindirectly, through the anomalous magnetic moment and the Lamb shift.\n(A point particle has no anomalous magnetic moment since it satisfies\nthe Dirac equation exactly.)\nThere was a long thread about\nthis last year on s.p.r. The results are summarized in my theoretical\nphysics FAQ at http://www.mat.univie.ac.at/~neum/physics-faq.txt\n\n\nArnold Neumaier\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>Franz Heymann wrote:
> The radial extent of the
> charge distribution of the electron has been measured. It is
> consistent with being a point object, to withinn a resolution of
> 2.8*10^-19 metres.
> The actual sitution is that the electron is, as best we know, a point
> particle
No. Only the bare electron is a point particle. The physical electron is
not, since it has a nontrivial form factor, which can be measured
indirectly, through the anomalous magnetic moment and the Lamb shift.
(A point particle has no anomalous magnetic moment since it satisfies
the Dirac equation exactly.)
There was a long thread about
this last year on s.p.r. The results are summarized in my theoretical
physics FAQ at http://www.mat.univie.ac.at/~neum/physics-faq.txt
Arnold Neumaier
Franz Heymann
Aug31-04, 03:55 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"Arnold Neumaier" <Arnold.Neumaier@univie.ac.at> wrote in message\nnews:4132F328.2050803@univie.ac.at...\n> Franz Heymann wrote:\n>\n> > The radial extent of the\n> > charge distribution of the electron has been measured. It is\n> > consistent with being a point object, to withinn a resolution of\n> > 2.8*10^-19 metres.\n> > The actual sitution is that the electron is, as best we know, a\npoint\n> > particle\n>\n> No. Only the bare electron is a point particle. The physical\nelectron is\n> not, since it has a nontrivial form factor, which can be measured\n> indirectly, through the anomalous magnetic moment and the Lamb\nshift.\n> (A point particle has no anomalous magnetic moment since it\nsatisfies\n> the Dirac equation exactly.)\n> There was a long thread about\n> this last year on s.p.r. The results are summarized in my\ntheoretical\n> physics FAQ at http://www.mat.univie.ac.at/~neum/physics-faq.txt\n\nThat\'s fine. I realise that the electron, including the paraphernalia\nof virtual particles which are part of its make-up does have a\nphysical extent. Even so, Joe Rongen\'s quote\n"Consider a single electron fired towards a photographic\nplate some distance away. Suppose the electron is literally a\nwave-coincident with the electron\'s state-function."\nis still incorrect. The electron is never a wave. It is a small\nentity whose *dynamics* is governed by a wave function\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>"Arnold Neumaier" <Arnold.Neumaier@univie.ac.at> wrote in message
news:4132F328.2050803@univie.ac.at...
> Franz Heymann wrote:
>
> > The radial extent of the
> > charge distribution of the electron has been measured. It is
> > consistent with being a point object, to withinn a resolution of
> > 2.8*10^-19 metres.
> > The actual sitution is that the electron is, as best we know, a
point
> > particle
>
> No. Only the bare electron is a point particle. The physical
electron is
> not, since it has a nontrivial form factor, which can be measured
> indirectly, through the anomalous magnetic moment and the Lamb
shift.
> (A point particle has no anomalous magnetic moment since it
satisfies
> the Dirac equation exactly.)
> There was a long thread about
> this last year on s.p.r. The results are summarized in my
theoretical
> physics FAQ at http://www.mat.univie.ac.at/~neum/physics-faq.txt
That's fine. I realise that the electron, including the paraphernalia
of virtual particles which are part of its make-up does have a
physical extent. Even so, Joe Rongen's quote
"Consider a single electron fired towards a photographic
plate some distance away. Suppose the electron is literally a
wave-coincident with the electron's state-function."
is still incorrect. The electron is never a wave. It is a small
entity whose *dynamics* is governed by a wave function
Franz
Boris Borcic
Aug31-04, 03:55 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\nArnold Neumaier wrote:\n> John T Lowry wrote:\n>\n>>The most coherent (not a pun) point of view, IMO, is that the wave funct\n>>ion is descriptive of an ensemble of similarly prepared electrons, NOT\n>>of this individual electron. My suggestion is that your next read be\n>>into the AAPT collection "Foundations of QM Since the Bell Inequalities"\n>>edited by L.E. Ballentine, or his equally persuasive and very thorough\n>>textbook, "Quantum Mechanics: A Modern Development." You\'ll like them.\n>\n>\n> Its main linitation is that it does not apply to systems that are so large\n> that they are unique. Today no one disputes that the sun is governed by\n> quantum mechanics.\n\nDoes anybody ever use a qm wave-function to describe the sun as a whole,\nto any sound and useful purpose ?\n\n> But one cannot apply statistical reasoning to the sun\n> as a whole.\n\nHum. What about black holes ?\n\n>\n> Thus Ballentine\'s interpretation cannot be the last word on the matter.\n\nWell, I\'d really like a discussion of the information loss paradox\nthat would either explain it away, or rule out such an explanation,\nin terms of what you call Ballentine\'s interpretation applied\nto infalling matter. If the wavefunction represents an ensemble,\nthen there is something to say for the vicinity of a BH horizon\nor singularity creating problems to the agregating of measurements\nthat\'s implied by the wavefunction representation.\n\nRegards, Boris Borcic\n--\nArchimedes engineered weapons, but he was risking his life, wasn\'t he ?\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>Arnold Neumaier wrote:
> John T Lowry wrote:
>
>>The most coherent (not a pun) point of view, IMO, is that the wave funct
>>ion is descriptive of an ensemble of similarly prepared electrons, NOT
>>of this individual electron. My suggestion is that your next read be
>>into the AAPT collection "Foundations of QM Since the Bell Inequalities"
>>edited by L.E. Ballentine, or his equally persuasive and very thorough
>>textbook, "Quantum Mechanics: A Modern Development." You'll like them.
>
>
> Its main linitation is that it does not apply to systems that are so large
> that they are unique. Today no one disputes that the sun is governed by
> quantum mechanics.
Does anybody ever use a qm wave-function to describe the sun as a whole,
to any sound and useful purpose ?
> But one cannot apply statistical reasoning to the sun
> as a whole.
Hum. What about black holes ?
>
> Thus Ballentine's interpretation cannot be the last word on the matter.
Well, I'd really like a discussion of the information loss paradox
that would either explain it away, or rule out such an explanation,
in terms of what you call Ballentine's interpretation applied
to infalling matter. If the wavefunction represents an ensemble,
then there is something to say for the vicinity of a BH horizon
or singularity creating problems to the agregating of measurements
that's implied by the wavefunction representation.
Regards, Boris Borcic
--
Archimedes engineered weapons, but he was risking his life, wasn't he ?
Arnold Neumaier
Aug31-04, 05:06 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>\nBoris Borcic wrote:\n> Arnold Neumaier wrote:\n>\n>>John T Lowry wrote:\n>>\n>>>The most coherent (not a pun) point of view, IMO, is that the wave funct\n>>>ion is descriptive of an ensemble of similarly prepared electrons, NOT\n>>>of this individual electron. My suggestion is that your next read be\n>>>into the AAPT collection "Foundations of QM Since the Bell Inequalities"\n>>>edited by L.E. Ballentine, or his equally persuasive and very thorough\n>>>textbook, "Quantum Mechanics: A Modern Development." You\'ll like them.\n>>\n>>Its main limitation is that it does not apply to systems that are so large\n>>that they are unique. Today no one disputes that the sun is governed by\n>>quantum mechanics.\n>\n> Does anybody ever use a qm wave-function to describe the sun as a whole,\n> to any sound and useful purpose ?\n\nNot that I know of. But if quantum mechanics is a universal theory of\nnature, it should also apply to the sun as a whole. At least we know that\nit applies to the extent that it governs the energy generating processes\nin the sun. However, the actual numerical analysis of models of the sun\nuse just treat the nuclear reactions within a classical reaction-diffusion\nframework, which (in principle; I don\'t know whether anyone has actually\ndone it) is derivable from QM using statistical mechanics arguments.\n\n\n\n>>But one cannot apply statistical reasoning to the sun as a whole.\n>\n> Hum. What about black holes ?\n\nI don\'t think one can apply statistical reasoning to a single black hole.\nOne can apply it, however, to many particles falling into a black hole.\n\n> Well, I\'d really like a discussion of the information loss paradox\n> that would either explain it away, or rule out such an explanation,\n> in terms of what you call Ballentine\'s interpretation applied\n> to infalling matter.\n\nUnfortunately, I don\'t understand enough about black holes to discuss this.\nI believe, however, that black holes are thermodynamic objects that cannot\nbe fundamental, for the same reasons that classical thermodynamics is not\na fundamental theory but derived from statistical mechanics.\n(But I might be wrong on this, given my limited understanding.)\n\n\nArnold Neumaier\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>Boris Borcic wrote:
> Arnold Neumaier wrote:
>
>>John T Lowry wrote:
>>
>>>The most coherent (not a pun) point of view, IMO, is that the wave funct
>>>ion is descriptive of an ensemble of similarly prepared electrons, NOT
>>>of this individual electron. My suggestion is that your next read be
>>>into the AAPT collection "Foundations of QM Since the Bell Inequalities"
>>>edited by L.E. Ballentine, or his equally persuasive and very thorough
>>>textbook, "Quantum Mechanics: A Modern Development." You'll like them.
>>
>>Its main limitation is that it does not apply to systems that are so large
>>that they are unique. Today no one disputes that the sun is governed by
>>quantum mechanics.
>
> Does anybody ever use a qm wave-function to describe the sun as a whole,
> to any sound and useful purpose ?
Not that I know of. But if quantum mechanics is a universal theory of
nature, it should also apply to the sun as a whole. At least we know that
it applies to the extent that it governs the energy generating processes
in the sun. However, the actual numerical analysis of models of the sun
use just treat the nuclear reactions within a classical reaction-diffusion
framework, which (in principle; I don't know whether anyone has actually
done it) is derivable from QM using statistical mechanics arguments.
>>But one cannot apply statistical reasoning to the sun as a whole.
>
> Hum. What about black holes ?
I don't think one can apply statistical reasoning to a single black hole.
One can apply it, however, to many particles falling into a black hole.
> Well, I'd really like a discussion of the information loss paradox
> that would either explain it away, or rule out such an explanation,
> in terms of what you call Ballentine's interpretation applied
> to infalling matter.
Unfortunately, I don't understand enough about black holes to discuss this.
I believe, however, that black holes are thermodynamic objects that cannot
be fundamental, for the same reasons that classical thermodynamics is not
a fundamental theory but derived from statistical mechanics.
(But I might be wrong on this, given my limited understanding.)
Arnold Neumaier
Franz Heymann
Aug31-04, 02:40 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>"Joe Rongen" <joe@alpha.to> wrote in message\nnews:cgt89d02k2e@enews2.newsguy.com...\n> "Greysky" <greyskynospam@sbcglobal.net> wrote in\n> message news:7A4Yc.9068\\$QJ3.4187@newssvr21.news.prodigy. com...\n> [snip]\n>\n> > May I point out that the electron wave is an Imaginary entity.\nThere\n> > are no special rules limiting how fast an imaginary wave may\ncollapse.\n> > The event we can measure is real in the sense that it contains\ninformation\n> > about the pre - collapsed matter wave while it is in this\nimaginary\n> > state... what this tells me is that the universe does not\ndistinguish\n> > between what is \'real\' and what is \'imaginary\' as long as we make\nno\n> > measurements.\n>\n> Thank you. One question, should one substitute the\n> word "imaginary" in the above with "indeterminate"?\n\nNo, but one should replace it by "complex"\n\nFranz\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>"Joe Rongen" <joe@\alpha.to> wrote in message
news:cgt89d02k2e@enews2.newsguy.com...
> "Greysky" <greyskynospam@sbcglobal.net> wrote in
> message news:7A4Yc.9068$QJ3.4187@newssvr21.news.prodigy.co m...
> [snip]
>
> > May I point out that the electron wave is an Imaginary entity.
There
> > are no special rules limiting how fast an imaginary wave may
collapse.
> > The event we can measure is real in the sense that it contains
information
> > about the pre - collapsed matter wave while it is in this
imaginary
> > state... what this tells me is that the universe does not
distinguish
> > between what is 'real' and what is 'imaginary' as long as we make
no
> > measurements.
>
> Thank you. One question, should one substitute the
> word "imaginary" in the above with "indeterminate"?
No, but one should replace it by "complex"
Franz
Joe Rongen
Sep1-04, 03:23 PM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>"Franz Heymann" <notfranz.heymann@btopenworld.com>\nwrote in message news:ch05h7\\$ami\\$1@sparta.btinternet.com...\n>\ n>\n> "Arnold Neumaier" <Arnold.Neumaier@univie.ac.at> wrote in message\n> news:4132F328.2050803@univie.ac.at...\n> > Franz Heymann wrote:\n> >\n> > > The radial extent of the\n> > > charge distribution of the electron has been measured. It is\n> > > consistent with being a point object, to withinn a resolution of\n> > > 2.8*10^-19 metres.\n> > > The actual sitution is that the electron is, as best we know, a\n> > > point particle\n> >\n> > No. Only the bare electron is a point particle. The physical\n> > electron is not, since it has a nontrivial form factor, which can\n> > be measured indirectly, through the anomalous magnetic moment\n> > and the Lamb shift.\n> > (A point particle has no anomalous magnetic moment since it\n> > satisfies the Dirac equation exactly.)\n> > There was a long thread about\n> > this last year on s.p.r. The results are summarized in my\n> > theoretical\n> > physics FAQ at http://www.mat.univie.ac.at/~neum/physics-faq.txt\n>\n> That\'s fine. I realise that the electron, including the paraphernalia\n> of virtual particles which are part of its make-up does have a\n> physical extent. Even so, Joe Rongen\'s quote\n> "Consider a single electron fired towards a photographic\n> plate some distance away. Suppose the electron is literally a\n> wave-coincident with the electron\'s state-function."\n> is still incorrect. The electron is never a wave. It is a small\n> entity whose *dynamics* is governed by a wave function\n>\n> Franz\n\n\nRegarding electrons and waves, here is another example.\nFrom:\n\n"Intermediate Quantum Mechanics" Third Edition, 1997\nby: Hans A.Bethe, Roman Jackiw, ISBN 0-201-32831-3\n\n.....While discussing an estimate for the exchange term in\nthe Hartree-Fock theory by using electron wave functions\ngiven by the Thomas-Fermi model of the atom, page 72:\n\n---------\n"We assume the electrons move in a constant potential\nand hence the wave functions are plane waves. ...."\n---------\n\nAnd that puts us right back to the original quote where Henry\nKrips proved that an electron could not be a "plane wave".\n\nNo wonder QM is sooo difficult to understand.... :-)\n\nRegards Joe\n\n\n---\nOutgoing mail is certified Virus Free.\nChecked by AVG anti-virus system (http://www.grisoft.com).\nVersion: 6.0.747 / Virus Database: 499 - Release Date: 9/1/04\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>"Franz Heymann" <notfranz.heymann@btopenworld.com>
wrote in message news:ch05h7$ami$1@sparta.btinternet.com...
>
>
> "Arnold Neumaier" <Arnold.Neumaier@univie.ac.at> wrote in message
> news:4132F328.2050803@univie.ac.at...
> > Franz Heymann wrote:
> >
> > > The radial extent of the
> > > charge distribution of the electron has been measured. It is
> > > consistent with being a point object, to withinn a resolution of
> > > 2.8*10^-19 metres.
> > > The actual sitution is that the electron is, as best we know, a
> > > point particle
> >
> > No. Only the bare electron is a point particle. The physical
> > electron is not, since it has a nontrivial form factor, which can
> > be measured indirectly, through the anomalous magnetic moment
> > and the Lamb shift.
> > (A point particle has no anomalous magnetic moment since it
> > satisfies the Dirac equation exactly.)
> > There was a long thread about
> > this last year on s.p.r. The results are summarized in my
> > theoretical
> > physics FAQ at http://www.mat.univie.ac.at/~neum/physics-faq.txt
>
> That's fine. I realise that the electron, including the paraphernalia
> of virtual particles which are part of its make-up does have a
> physical extent. Even so, Joe Rongen's quote
> "Consider a single electron fired towards a photographic
> plate some distance away. Suppose the electron is literally a
> wave-coincident with the electron's state-function."
> is still incorrect. The electron is never a wave. It is a small
> entity whose *dynamics* is governed by a wave function
>
> Franz
Regarding electrons and waves, here is another example.
From:
"Intermediate Quantum Mechanics" Third Edition, 1997
by: Hans A.Bethe, Roman Jackiw, ISBN 0-201-32831-3
.....While discussing an estimate for the exchange term in
the Hartree-Fock theory by using electron wave functions
given by the Thomas-Fermi model of the atom, page 72:
---------
"We assume the electrons move in a constant potential
and hence the wave functions are plane waves. ...."
---------
And that puts us right back to the original quote where Henry
Krips proved that an electron could not be a "plane wave".
No wonder QM is sooo difficult to understand.... :-)
Regards Joe
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6..747 / Virus Database: 499 - Release Date: 9/1/04
Arnold Neumaier:
>Decoherence is the decay of off-diagonal contributions
>in a density matrix....
Kurious:
This is a link that shows a visual depiction of decoherence:
http://www.geocities.com/scjphysicist/decoh.html
and this is a link with the technical details of decoherence:
http://www.ece.rochester.edu/~habif...decoherence.htm
They may prove useful in this debate.
Patrick Powers
Sep6-04, 03:47 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>\nkurious <alistair@goforit64.fsnet.co.uk> wrote in message news:<kurious.1bzcjq@physicsforums.com>...\n> Arnold Neumaier:\n> >Decoherence is the decay of off-diagonal contributions\n> >in a density matrix....\n>\n> Kurious:\n> This is a link that shows a visual depiction of decoherence:\n> http://www.geocities.com/scjphysicist/decoh.html\n>\n\nIt looks very nice, but what does all this motion mean?\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>kurious <alistair@goforit64.fsnet.co.uk> wrote in message news:<kurious.1bzcjq@physicsforums.com>...
> Arnold Neumaier:
> >Decoherence is the decay of off-diagonal contributions
> >in a density matrix....
>
> Kurious:
> This is a link that shows a visual depiction of decoherence:
> http://www.geocities.com/scjphysicist/decoh.html
>
It looks very nice, but what does all this motion mean?
I have the following question which I hope one of you would answer:-
Decoherence is invaraiably accompanied with dissipation--so if you've a two level system,in the state a(t)|0>+b(t)|1>, interacting with an environment,you should expect two things:-1.the off-diagonal elements of the density matrix should vanish,2.Because of dissipation, the system should decay to the state |0>--so that you are left with only one diagonal element in the density matrix.Does this not solve the measurement problem?After all the whole aim of the measurement problem is to get at only of the diagonal elements---my whole point is that the so called decoherence(vanishing of the off-diagonal elements) is invariably accompanied with dissipation which would ensure that only one of the diagonal elements survives.
If there is anything wrong with my arguments kindly point out the same to me.
Jagmeet Singh
Arnold Neumaier
Sep20-04, 01:43 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>\n\ngptejms wrote:\n> I have the following question which I hope one of you would answer:-\n>\n> Decoherence is invaraiably accompanied with dissipation--so if you\'ve a\n> two level system,in the state a(t)|0>+b(t)|1>, interacting with an\n> environment,you should expect two things:-1.the off-diagonal elements\n> of the density matrix should vanish,2.Because of dissipation, the\n> system should decay to the state |0>--so that you are left with only\n> one diagonal element in the density matrix.Does this not solve the\n> measurement problem?\n\nThe devil is in the details. To make your argument work, you\'d be able to\nshow that what you say \'should\' happen actually happens as a consequence of\nthe known dynamical laws. But it will not.\n\nThe states are hopelessly oscillating and not converging to anything.\nOnly the reduced density matrices converge under suitable conditions.\n\n\nArnold Neumaier\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>gptejms wrote:
> I have the following question which I hope one of you would answer:-
>
> Decoherence is invaraiably accompanied with dissipation--so if you've a
> two level system,in the state a(t)|0>+b(t)|1>, interacting with an
> environment,you should expect two things:-1.the off-diagonal elements
> of the density matrix should vanish,2.Because of dissipation, the
> system should decay to the state |0>--so that you are left with only
> one diagonal element in the density matrix.Does this not solve the
> measurement problem?
The devil is in the details. To make your argument work, you'd be able to
show that what you say 'should' happen actually happens as a consequence of
the known dynamical laws. But it will not.
The states are hopelessly oscillating and not converging to anything.
Only the reduced density matrices converge under suitable conditions.
Arnold Neumaier
Arnold Neumaier
Sep20-04, 01:43 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>\n\nkurious wrote:\n> and this is a link with the technical details of decoherence:\n> http://www.ece.rochester.edu/~habif...decoherence.htm\n\nmaybe you\'d give the full link; the hybrid given is not valid...\n\n\nArnold Neumaier\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>kurious wrote:
> and this is a link with the technical details of decoherence:
> http://www.ece.rochester.edu/~habif...decoherence.htm
maybe you'd give the full link; the hybrid given is not valid...
Arnold Neumaier
alistair
Sep22-04, 03:45 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\nArnold Neumaier <Arnold.Neumaier@univie.ac.at> wrote in message news:<414EEFF4.1050909@univie.ac.at>...\n> kurious wrote:\n> > and this is a link with the technical details of decoherence:\n> > http://www.ece.rochester.edu/~habif...decoherence.htm\n>\n> maybe you\'d give the full link; the hybrid given is not valid...\n\n\nhttp://www.ece.rochester.edu/~habif/Web/Research/decoherence.htm\n\nDiscusses decoherence and includes an example of a SQUID with graphs.\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>Arnold Neumaier <Arnold.Neumaier@univie.ac.at> wrote in message news:<414EEFF4.1050909@univie.ac.at>...
> kurious wrote:
> > and this is a link with the technical details of decoherence:
> > http://www.ece.rochester.edu/~habif...decoherence.htm
>
> maybe you'd give the full link; the hybrid given is not valid...
http://www.ece.rochester.edu/~habif/Web/Research/decoherence.htm
Discusses decoherence and includes an example of a SQUID with graphs.
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