Hayden McGuinness
Aug12-04, 08:29 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\nSay you have two people each storing one particle of an entangled\npair, particles A and B, who are arbitrarily far away with the state\nof this system being initially phi+ = [|A:0>|B:1> + |B:0>|A:1>] where\n|0> or |1> are orthogonal quantitative of some particular parameter\nlike spin, polarization, etc. Now say the person storing A performs a\nunitary operation on A so that the system is in one of the equally\nprobable four bell states\n\n1. phi+ = [|A:0>|B:1> + |B:0>|A:1>]\n2. phi- = [|A:0>|B:1> - |B:0>|A:1>]\n3. theta+ = [|A:0>|B:0> + |B:1>|A:1>]\n4. theta- = [|A:0>|B:0> - |B:1>|A:1>]\n\nwhich is known to the performer of the operation (i.e. they know what\nthey did) but of course not known to the keeper of B. Is there *any*\nway (by interacting particle B with other particles, performing\nunitary or otherwise operations on it, measuring it (collapse), etc)\nthe keeper of particle B can deduce the state the system with a degree\nof confidence higher than 25% , i.e. better than a random guess,\n*without* interacting B with A (hence the separation)? Is it easier to\npredict if the system happens to be in one of these states rather than\nthe others? The answer can be of any kind of particle with any\nparameter, although photons and polarization would be preferred.\n\nThanks,\nHayden\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>Say you have two people each storing one particle of an entangled
pair, particles A and B, who are arbitrarily far away with the state
of this system being initially \phi+ = [|A:0>|B:1> + |B:0>|A:1>] where
|0> or |1> are orthogonal quantitative of some particular parameter
like spin, polarization, etc. Now say the person storing A performs a
unitary operation on A so that the system is in one of the equally
probable four bell states
1. \phi+ = [|A:0>|B:1> + |B:0>|A:1>]2. \phi- = [|A:0>|B:1> - |B:0>|A:1>]3. \theta+ = [|A:0>|B:0> + |B:1>|A:1>]4. \theta- = [|A:0>|B:0> - |B:1>|A:1>]
which is known to the performer of the operation (i.e. they know what
they did) but of course not known to the keeper of B. Is there *any*
way (by interacting particle B with other particles, performing
unitary or otherwise operations on it, measuring it (collapse), etc)
the keeper of particle B can deduce the state the system with a degree
of confidence higher than 25% , i.e. better than a random guess,
*without* interacting B with A (hence the separation)? Is it easier to
predict if the system happens to be in one of these states rather than
the others? The answer can be of any kind of particle with any
parameter, although photons and polarization would be preferred.
Thanks,
Hayden
pair, particles A and B, who are arbitrarily far away with the state
of this system being initially \phi+ = [|A:0>|B:1> + |B:0>|A:1>] where
|0> or |1> are orthogonal quantitative of some particular parameter
like spin, polarization, etc. Now say the person storing A performs a
unitary operation on A so that the system is in one of the equally
probable four bell states
1. \phi+ = [|A:0>|B:1> + |B:0>|A:1>]2. \phi- = [|A:0>|B:1> - |B:0>|A:1>]3. \theta+ = [|A:0>|B:0> + |B:1>|A:1>]4. \theta- = [|A:0>|B:0> - |B:1>|A:1>]
which is known to the performer of the operation (i.e. they know what
they did) but of course not known to the keeper of B. Is there *any*
way (by interacting particle B with other particles, performing
unitary or otherwise operations on it, measuring it (collapse), etc)
the keeper of particle B can deduce the state the system with a degree
of confidence higher than 25% , i.e. better than a random guess,
*without* interacting B with A (hence the separation)? Is it easier to
predict if the system happens to be in one of these states rather than
the others? The answer can be of any kind of particle with any
parameter, although photons and polarization would be preferred.
Thanks,
Hayden