FTL by Down-converting [Archive]

Horace Heffner

Oct25-04, 10:42 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\nFTL by Down-converting\n\nA method is proposed here to achieve faster than light (FTL) communication\nby the use of down-converters. A down-converter splits a photon into two\nphotons each having half the energy of the original photon.\n\nSuppose we have a sender Alice, a receiver Bob, and an intermediary\nfacilitator Charlie. Charlie uses a beam splitter to create two beams of\nlaser light: L the left beam and R, the right beam. Charlie then\ndown-converts the L beam to create beams L1 and L2, and similarly creates\nbeams R1 and R2 from the beam R. Beams R2 and L2 are normal path or\n"signal" photons through the down-converter, while beams R1 and L1 are\ncalled "idler" photons. "Beam"here means a flow of individually\ndetectable photons sent in very short intervals so as to provide a useful\nrate of communication. Charlie directs beams L1 and R1 to Alice and beams\nR2 and L2 to Bob. The corresponding photons arrive at both Bob and Alice\nat nearly the same time, but here assume Alice receives hers first, but\njust barely before Bob.\n\nBob directs beams R2 and L2 such that they can create an interference\npattern in a set of detectors arranged so it is feasible to rapidly and\nwith high probability determine whether an interference pattern is present\nor not. The signal photon beams R2 and L2 can create such an interference\npattern because they are the two paths from a beam splitter.\n\nBob will in fact see such an interference pattern provided Alice does not\nput detectors in idler beams R1 and L1.[1] If Alice does place detectors\nin both her beams, then this is equivalent to knowing which path each of\nBob\'s photons have traveled, and thus Bob can observe no interference\npattern. This known-path-no-interference result has been characteristic\nof numerous versions of the two slit or two path interference\nexperiments.[2] If Alice sees an idler she knows which path the\ncorresponding signal photon took to Bob, and the interference wavefunction\ninstantly collapses. Bob, when his photons arrive shortly after Alice\'s\ncorresponding photons, knows the current state of Alice\'s detectors by\nwhether he sees an interference pattern or not.\n\nSince Alice and Bob could be light years away from each other, and since\nAlice thus might have years from the time Charlie released the photons to\nmake the choice to detect or not detect her photons, faster than light\ncommunication from Alice to Bob is clearly a possible result. It might be\nsaid that the communication can not be verified for years, but such\nverification is in this case is not necessary. Bob does not require\nverification or comparison to Alice\'s results to know the immediate state\nof Alice\'s detectors, or to immediately detect a change of state of those\ndetectors, with sufficient speed and reliability to establish a practical\ncommunication channel. Further, a similar channel can be established from\nBob to Alice, thus permitting immediate error detection and correction or\nretransmission.\n\nAssuming that beams adequate for fast communication can be generated and\nthe resulting interference detected sufficiently fast, achieving high data\nrate FTL communication at short range then primarily boils down to how\nfast Alice can switch from a detecting mode to a non-detecting mode. This\nmight be as simple as her redirecting beams R1 and/or L1, or by switching\non and off the information from her detectors. This experiment then, in\naddition to achieving FTL communication, may be useful for determining\nexactly of what an observation consists.\n\nAn experiment requiring the simplest possible message would involve\nsending a data bit (actually only a change of state) via a one-way FTL\ncommunication channel and returning it via a second one-way return FTL\ncommunication channel, and repeating this process to establish an\noscillation. A fiber pair from Charlie to Bob and Charlie to Alice could\nbe used, if desired, to create a single FTL communication channel. A\nsimilar set of fiber pairs would be used for the return channel. To\ndemonstrate FTL communication it is then necessary to transmit over a\nsufficient distance D that the oscillation frequency, f, is faster than\nthe oscillation frequency F = c/D that can be achieved by light. A 10 km\ncommunication link (each way) need only cycle faster than about 15 kHz to\nbreak the light speed barrier. Assuming a sample of 100 photons to be\nsufficient for determining interference, a photon transmission and\ndetection rate of 1.5 million photons per second is required. However, it\nis not known what precisely constitutes an observation. It may be that\nindividual photon detection is not even necessary, but rather mere beam\nintensity determination.\n\nReferences:\n\n[1] Kim et al, Phys. Rev. Lett., Vol 84, no. 1, pp 1-5\n[2] Brian Green, *The Fabric of the Cosmos*, (New York, Alfred A Knopf,\n2004), pp 193-197\n\nRegards,\n\nHorace Heffner\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>FTL by Down-converting

A method is proposed here to achieve faster than light (FTL) communication
by the use of down-converters. A down-converter splits a photon into two
photons each having half the energy of the original photon.

Suppose we have a sender Alice, a receiver Bob, and an intermediary
facilitator Charlie. Charlie uses a beam splitter to create two beams of
laser light: L the left beam and R, the right beam. Charlie then
down-converts the L beam to create beams L1 and L2, and similarly creates
beams R1 and R2 from the beam R. Beams R2 and L2 are normal path or
"signal" photons through the down-converter, while beams R1 and L1 are
called "idler" photons. "Beam"here means a flow of individually
detectable photons sent in very short intervals so as to provide a useful
rate of communication. Charlie directs beams L1 and R1 to Alice and beams
R2 and L2 to Bob. The corresponding photons arrive at both Bob and Alice
at nearly the same time, but here assume Alice receives hers first, but
just barely before Bob.

Bob directs beams R2 and L2 such that they can create an interference
pattern in a set of detectors arranged so it is feasible to rapidly and
with high probability determine whether an interference pattern is present
or not. The signal photon beams R2 and L2 can create such an interference
pattern because they are the two paths from a beam splitter.

Bob will in fact see such an interference pattern provided Alice does not
put detectors in idler beams R1 and L1.[1] If Alice does place detectors
in both her beams, then this is equivalent to knowing which path each of
Bob's photons have traveled, and thus Bob can observe no interference
pattern. This known-path-no-interference result has been characteristic
of numerous versions of the two slit or two path interference
experiments.[2] If Alice sees an idler she knows which path the
corresponding signal photon took to Bob, and the interference wavefunction
instantly collapses. Bob, when his photons arrive shortly after Alice's
corresponding photons, knows the current state of Alice's detectors by
whether he sees an interference pattern or not.

Since Alice and Bob could be light years away from each other, and since
Alice thus might have years from the time Charlie released the photons to
make the choice to detect or not detect her photons, faster than light
communication from Alice to Bob is clearly a possible result. It might be
said that the communication can not be verified for years, but such
verification is in this case is not necessary. Bob does not require
verification or comparison to Alice's results to know the immediate state
of Alice's detectors, or to immediately detect a change of state of those
detectors, with sufficient speed and reliability to establish a practical
communication channel. Further, a similar channel can be established from
Bob to Alice, thus permitting immediate error detection and correction or
retransmission.

Assuming that beams adequate for fast communication can be generated and
the resulting interference detected sufficiently fast, achieving high data
rate FTL communication at short range then primarily boils down to how
fast Alice can switch from a detecting mode to a non-detecting mode. This
might be as simple as her redirecting beams R1 and/or L1, or by switching
on and off the information from her detectors. This experiment then, in
addition to achieving FTL communication, may be useful for determining
exactly of what an observation consists.

An experiment requiring the simplest possible message would involve
sending a data bit (actually only a change of state) via a one-way FTL
communication channel and returning it via a second one-way return FTL
communication channel, and repeating this process to establish an
oscillation. A fiber pair from Charlie to Bob and Charlie to Alice could
be used, if desired, to create a single FTL communication channel. A
similar set of fiber pairs would be used for the return channel. To
demonstrate FTL communication it is then necessary to transmit over a
sufficient distance D that the oscillation frequency, f, is faster than
the oscillation frequency F = c/D that can be achieved by light. A 10 km
communication link (each way) need only cycle faster than about 15 kHz to
break the light speed barrier. Assuming a sample of 100 photons to be
sufficient for determining interference, a photon transmission and
detection rate of 1.5 million photons per second is required. However, it
is not known what precisely constitutes an observation. It may be that
individual photon detection is not even necessary, but rather mere beam
intensity determination.

References:

[1] Kim et al, Phys. Rev. Lett., Vol 84, no. 1, pp 1-5
[2] Brian Green, *The Fabric of the Cosmos*, (New York, Alfred A Knopf,
2004), pp 193-197

Regards,

Horace Heffner

Ralph Hartley

Oct27-04, 10:55 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\nHorace Heffner wrote:\n> FTL by Down-converting\n\nFiguring out why such schemes don\'t work can be an interesting puzzle,\nsimilar to figuring out perpetual motion machines, but this one is way too\neasy.\n\n> [...] A down-converter splits a photon into two photons each having half\n> the energy of the original photon.\n>\n> Suppose we have a sender Alice, a receiver Bob, [...] a beam splitter\n> create[s] two beams of laser light: L the left beam and R, the right\n> beam. Charlie then down-converts the L beam to create beams L1 and L2,\n> and similarly creates beams R1 and R2 from the beam R L1 and R1 [go] to\n> Alice and beams R2 and L2 to Bob. The corresponding photons arrive at\n> both Bob and Alice at nearly the same time, but here assume Alice\n> receives hers first, but just barely before Bob.\n>\n> Bob directs beams R2 and L2 such that they can create an interference\n> pattern [...] The signal photon beams R2 and L2 can create such an\n> interference pattern because they are the two paths from a beam\n> splitter.\n>\n> Bob will in fact see such an interference pattern provided Alice does\n> not put detectors in idler beams R1 and L1.[1] If Alice does place\n> detectors in both her beams, then this is equivalent to knowing which\n> path each of Bob\'s photons have traveled, and thus Bob can observe no\n> interference pattern.\n\nThe existence of R1 and L1 prevent Bob from seeing an interference pattern\nregardless of what Alice does.\n\nThis is related to the famous "no cloning" theorem.\n\nTo see that this must be so, consider the case where the photons reach\nAlice *after* Bob. Alice can transmit the information back to Bob, who then\nknows which path his photons followed. If Bob can determine the path he\ndoesn\'t see interference.\n\nThe error is in assuming that a part of the system that is never measured\ncan just be ignored. Quantum Mechanics has a procedure for getting a\ndescription of a part of a system from a description of the whole system,\nknown as a "partial trace".\n\nBasically, it amounts to averaging over the possible states of the excluded\nparts. In this case the system consists of L1, R1, L2, and R2. If L1 and R1\nescape to infinity without being measured, we need to trace over (a kind of\naverage) them to get the state of L2 and R2.\n\nThe result is a "mixed" state, in which there is no interference.\n\nThere are ways for Alice to "erase" the path information in L1 and R1, and\nrestore the interference, but because QM preserves information, they all\nrequire her to have access to L2 and R2.\n\nRalph Hartley\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>Horace Heffner wrote:
> FTL by Down-converting

Figuring out why such schemes don't work can be an interesting puzzle,
similar to figuring out perpetual motion machines, but this one is way too
easy.

> [...] A down-converter splits a photon into two photons each having half
> the energy of the original photon.
>
> Suppose we have a sender Alice, a receiver Bob, [...] a beam splitter
> create[s] two beams of laser light: L the left beam and R, the right
> beam. Charlie then down-converts the L beam to create beams L1 and L2,
> and similarly creates beams R1 and R2 from the beam R L1 and R1 [go] to
> Alice and beams R2 and L2 to Bob. The corresponding photons arrive at
> both Bob and Alice at nearly the same time, but here assume Alice
> receives hers first, but just barely before Bob.
>
> Bob directs beams R2 and L2 such that they can create an interference
> pattern [...] The signal photon beams R2 and L2 can create such an
> interference pattern because they are the two paths from a beam
> splitter.
>
> Bob will in fact see such an interference pattern provided Alice does
> not put detectors in idler beams R1 and L1.[1] If Alice does place
> detectors in both her beams, then this is equivalent to knowing which
> path each of Bob's photons have traveled, and thus Bob can observe no
> interference pattern.

The existence of R1 and L1 prevent Bob from seeing an interference pattern
regardless of what Alice does.

This is related to the famous "no cloning" theorem.

To see that this must be so, consider the case where the photons reach
Alice *after* Bob. Alice can transmit the information back to Bob, who then
knows which path his photons followed. If Bob can determine the path he
doesn't see interference.

The error is in assuming that a part of the system that is never measured
can just be ignored. Quantum Mechanics has a procedure for getting a
description of a part of a system from a description of the whole system,
known as a "partial trace".

Basically, it amounts to averaging over the possible states of the excluded
parts. In this case the system consists of L1, R1, L2, and R2. If L1 and R1
escape to infinity without being measured, we need to trace over (a kind of
average) them to get the state of L2 and R2.

The result is a "mixed" state, in which there is no interference.

There are ways for Alice to "erase" the path information in L1 and R1, and
restore the interference, but because QM preserves information, they all
require her to have access to L2 and R2.

Ralph Hartley

Patrick Van Esch

Oct27-04, 10:55 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\nhheffner@mtaonline.net (Horace Heffner) wrote in message news:<hheffner-2510040558170001@dialups-321.palmer.mtaonline.net>...\n\n>\n> [1] Kim et al, Phys. Rev. Lett., Vol 84, no. 1, pp 1-5\n\n\nIf you look carefully at the results of this paper, you will see that\nthe interference patterns are "subsampled" coincidences with the\nmiddle detectors, and moreover that the two different interference\npatterns are shifted in such a way, that when you ignore which one you\ntake, you loose the interference. So if Bob doesn\'t get this\n"coincidence" click, he will take ALL photons, and there won\'t be any\ninterference visible. It is only when he selects those events which\nhad the right click in ONE of the two detectors, that he might hope to\nsee an interference pattern emerge. So there is no FTL communication\npossible with this scheme.\nIt is always the case: locally at Bob\'s place, there is no statistical\ninformation which can be extracted from what happened at Alice\'s. It\nis only after putting the coincidences together that certain\ncorrelations emerge.\n\ncheers,\npatrick.\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>hheffner@mtaonline.net (Horace Heffner) wrote in message news:<hheffner-2510040558170001@dialups-321.palmer.mtaonline.net>...

>
> [1] Kim et al, Phys. Rev. Lett., Vol 84, no. 1, pp 1-5

If you look carefully at the results of this paper, you will see that
the interference patterns are "subsampled" coincidences with the
middle detectors, and moreover that the two different interference
patterns are shifted in such a way, that when you ignore which one you
take, you loose the interference. So if Bob doesn't get this
"coincidence" click, he will take ALL photons, and there won't be any
interference visible. It is only when he selects those events which
had the right click in ONE of the two detectors, that he might hope to
see an interference pattern emerge. So there is no FTL communication
possible with this scheme.
It is always the case: locally at Bob's place, there is no statistical
information which can be extracted from what happened at Alice's. It
is only after putting the coincidences together that certain
correlations emerge.

cheers,
patrick.

seratend

Oct27-04, 10:55 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\n\nhheffner@mtaonline.net (Horace Heffner) wrote in message news:<hheffner-2510040558170001@dialups-321.palmer.mtaonline.net>...\n> FTL by Down-converting\n>\n>\n> Bob will in fact see such an interference pattern provided Alice does not\n> put detectors in idler beams R1 and L1.[1] If Alice does place detectors\n> in both her beams, then this is equivalent to knowing which path each of\n> Bob\'s photons have traveled, and thus Bob can observe no interference\n> pattern.\n\nSo you beleave that the 50/50 satistics of Bob photons (|+>,|->) are\nsimply changed with an action of Alice at the end of the universe?\n\n\n\nSeratend\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>hheffner@mtaonline.net (Horace Heffner) wrote in message news:<hheffner-2510040558170001@dialups-321.palmer.mtaonline.net>...
> FTL by Down-converting
>
>
> Bob will in fact see such an interference pattern provided Alice does not
> put detectors in idler beams R1 and L1.[1] If Alice does place detectors
> in both her beams, then this is equivalent to knowing which path each of
> Bob's photons have traveled, and thus Bob can observe no interference
> pattern.

So you beleave that the 50/50 satistics of Bob photons (|+>,|->) are
simply changed with an action of Alice at the end of the universe?

Seratend

Uncle Al

Oct27-04, 10:56 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>\nHorace Heffner wrote:\n>\n> FTL by Down-converting\n>\n> A method is proposed here to achieve faster than light (FTL) communication\n> by the use of down-converters. A down-converter splits a photon into two\n> photons each having half the energy of the original photon.\n\nFTL anything violates causality. Violation of causality is not\nallowed within extant physics in weak field limits. You are already\nwrong. Einstein-Podolsky-Rosen experiments can transfer data\nsuperluminally (instantaneously!) through universal wavefunction\ncollapse, but data do not become information any faster than\nlightspeed. A primer must be sent and it travels by the book. You do\nnot even get FTL Morse code.\n\nThe details of your Gedankenexperiment are irrelevant. The entire\nclass of experiment will not work FTL.\n\n[snip]\n\n--\nUncle Al\nhttp://www.mazepath.com/uncleal/\n(Toxic URL! Unsafe for children and most mammals)\nhttp://www.mazepath.com/uncleal/qz.pdf\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>Horace Heffner wrote:
>
> FTL by Down-converting
>
> A method is proposed here to achieve faster than light (FTL) communication
> by the use of down-converters. A down-converter splits a photon into two
> photons each having half the energy of the original photon.

FTL anything violates causality. Violation of causality is not
allowed within extant physics in weak field limits. You are already
wrong. Einstein-Podolsky-Rosen experiments can transfer data
superluminally (instantaneously!) through universal wavefunction
collapse, but data do not become information any faster than
lightspeed. A primer must be sent and it travels by the book. You do
not even get FTL Morse code.

The details of your Gedankenexperiment are irrelevant. The entire
class of experiment will not work FTL.

[snip]

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf

chronon

Oct27-04, 11:00 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>hheffner@mtaonline.net (Horace Heffner) wrote in message news:<hheffner-2510040558170001@dialups-321.palmer.mtaonline.net>...\n> FTL by Down-converting\n>\n> A method is proposed here to achieve faster than light (FTL) communication\n> by the use of down-converters. A down-converter splits a photon into two\n> photons each having half the energy of the original photon.\n>\n\nI\'ve been thinking along similar lines, in fact just this morning I\ndid a Google search for "downconverting polarisation" (but I didn\'t\nfind anything useful). I think the problem is likely to be that a\ndownconverter doesn\'t preserve the relevant quantum state of the\nphoton, and so the device won\'t work.\n\nQuantum theory says that you can produce two particles with the \'same\'\nquantum state but not more than two. (\'same\' in the sense that they\ncan be equal and opposite). If you could produce three, four or more\nphotons in the same state then that would be a problem for quantum\ntheory.\n\nStephen Lee\nwww.chronon.org\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>hheffner@mtaonline.net (Horace Heffner) wrote in message news:<hheffner-2510040558170001@dialups-321.palmer.mtaonline.net>...
> FTL by Down-converting
>
> A method is proposed here to achieve faster than light (FTL) communication
> by the use of down-converters. A down-converter splits a photon into two
> photons each having half the energy of the original photon.
>

I've been thinking along similar lines, in fact just this morning I
did a Google search for "downconverting polarisation" (but I didn't
find anything useful). I think the problem is likely to be that a
downconverter doesn't preserve the relevant quantum state of the
photon, and so the device won't work.

Quantum theory says that you can produce two particles with the 'same'
quantum state but not more than two. ('same' in the sense that they
can be equal and opposite). If you could produce three, four or more
photons in the same state then that would be a problem for quantum
theory.

Stephen Lee
www.chronon.org

Horace Heffner

Oct28-04, 01:28 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>\nIn article <c23e597b.0410260528.3ce69b14@posting.google.com>, \nvanesch@ill.fr (Patrick Van Esch) wrote:\n\n> hheffner@mtaonline.net (Horace Heffner) wrote in message\nnews:<hheffner-2510040558170001@dialups-321.palmer.mtaonline.net>...\n>\n> >\n> > [1] Kim et al, Phys. Rev. Lett., Vol 84, no. 1, pp 1-5\n>\n>\n> If you look carefully at the results of this paper, you will see that\n> the interference patterns are "subsampled" coincidences with the\n> middle detectors, and moreover that the two different interference\n> patterns are shifted in such a way, that when you ignore which one you\n> take, you loose the interference. So if Bob doesn\'t get this\n> "coincidence" click, he will take ALL photons, and there won\'t be any\n> interference visible. It is only when he selects those events which\n> had the right click in ONE of the two detectors, that he might hope to\n> see an interference pattern emerge. So there is no FTL communication\n> possible with this scheme.\n\nThis is correct. Thank you for pointing this out. I have hopefully\ncorrected this problem in the new posting "FTL by Down-converting\n(Revised)"\n\n\n> It is always the case: locally at Bob\'s place, there is no statistical\n> information which can be extracted from what happened at Alice\'s. It\n> is only after putting the coincidences together that certain\n> correlations emerge.\n\nIf which-path information is lost for all photons then the interference\npattern should be the only pattern remaining, and knowledge of coincidence\nshould be irrelevant.\n\n>\n> cheers,\n> patrick.\n\nRegards,\n\nHorace Heffner\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>In article <c23e597b.0410260528.3ce69b14@posting.google.com>,
vanesch@ill.fr (Patrick Van Esch) wrote:

> hheffner@mtaonline.net (Horace Heffner) wrote in message
news:<hheffner-2510040558170001@dialups-321.palmer.mtaonline.net>...
>
> >
> > [1] Kim et al, Phys. Rev. Lett., Vol 84, no. 1, pp 1-5
>
>
> If you look carefully at the results of this paper, you will see that
> the interference patterns are "subsampled" coincidences with the
> middle detectors, and moreover that the two different interference
> patterns are shifted in such a way, that when you ignore which one you
> take, you loose the interference. So if Bob doesn't get this
> "coincidence" click, he will take ALL photons, and there won't be any
> interference visible. It is only when he selects those events which
> had the right click in ONE of the two detectors, that he might hope to
> see an interference pattern emerge. So there is no FTL communication
> possible with this scheme.

This is correct. Thank you for pointing this out. I have hopefully
corrected this problem in the new posting "FTL by Down-converting
(Revised)"

> It is always the case: locally at Bob's place, there is no statistical
> information which can be extracted from what happened at Alice's. It
> is only after putting the coincidences together that certain
> correlations emerge.

If which-path information is lost for all photons then the interference
pattern should be the only pattern remaining, and knowledge of coincidence
should be irrelevant.

>
> cheers,
> patrick.

Regards,

Horace Heffner

Horace Heffner

Nov3-04, 09:46 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>In article <clo6i4\\$psk\\$1@ra.nrl.navy.mil>, Ralph Hartley\n<hartley@aic.nrl.navy.mil> wrote:\n\n>\n> There are ways for Alice to "erase" the path information in L1 and R1, and\n> restore the interference, but because QM preserves information, they all\n> require her to have access to L2 and R2.\n>\n> Ralph Hartley\n\nThanks for the information. I would appreaciate your comments on the\napproach I just posted in "FTL by Down-converting (Revised)" which,\nsimilarly to ref [1] should restore interference, but not just for a\nsubset of R1 and L2, but for all photons on Bob\'s end.\n\nRegards,\n\nHorace Heffner\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>In article <clo6i4$psk$1@ra.nrl.navy.mil>, Ralph Hartley
<hartley@aic.nrl.navy.mil> wrote:

>
> There are ways for Alice to "erase" the path information in L1 and R1, and
> restore the interference, but because QM preserves information, they all
> require her to have access to L2 and R2.
>
> Ralph Hartley

Thanks for the information. I would appreaciate your comments on the
approach I just posted in "FTL by Down-converting (Revised)" which,
similarly to ref [1] should restore interference, but not just for a
subset of R1 and L2, but for all photons on Bob's end.

Regards,

Horace Heffner

Horace Heffner

Nov3-04, 09:46 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>In article <3ee76016.0410260508.1f25a04e@posting.google.com>, \nser_monmail@yahoo.fr (seratend) wrote:\n\n> hheffner@mtaonline.net (Horace Heffner) wrote in message\nnews:<hheffner-2510040558170001@dialups-321.palmer.mtaonline.net>...\n> > FTL by Down-converting\n> >\n> >\n> > Bob will in fact see such an interference pattern provided Alice does not\n> > put detectors in idler beams R1 and L1.[1] If Alice does place detectors\n> > in both her beams, then this is equivalent to knowing which path each of\n> > Bob\'s photons have traveled, and thus Bob can observe no interference\n> > pattern.\n>\n> So you beleave that the 50/50 satistics of Bob photons (|+>,|->) are\n> simply changed with an action of Alice at the end of the universe?\n\n\nIt is not my belief that is important. It is devising an experiment that\nwill let nature teach us something new that is the objective.\n\nRegards,\n\nHorace Heffner\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>In article <3ee76016.0410260508.1f25a04e@posting.google.com>,
ser_monmail@yahoo.fr (seratend) wrote:

> hheffner@mtaonline.net (Horace Heffner) wrote in message
news:<hheffner-2510040558170001@dialups-321.palmer.mtaonline.net>...
> > FTL by Down-converting
> >
> >
> > Bob will in fact see such an interference pattern provided Alice does not
> > put detectors in idler beams R1 and L1.[1] If Alice does place detectors
> > in both her beams, then this is equivalent to knowing which path each of
> > Bob's photons have traveled, and thus Bob can observe no interference
> > pattern.
>
> So you beleave that the 50/50 satistics of Bob photons (|+>,|->) are
> simply changed with an action of Alice at the end of the universe?

It is not my belief that is important. It is devising an experiment that
will let nature teach us something new that is the objective.

Regards,

Horace Heffner