changing the polarization of a photon Text

kurious

Jul27-04, 08:52 AM

How much energy does it take to change the polarization of a photon?
Can a gravitational wave change the polarization of a photon?

Franz Heymann

Jul28-04, 04:58 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"kurious" <alistair@goforit64.fsnet.co.uk> wrote in message\nnews:kurious.1a0it4@physicsforums.com...\n>\n>\n> How much energy does it take to change the polarization of a photon?\n\nNone\n\n> Can a gravitational wave change the polarization of a photon?\n\nNo\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>"kurious" <alistair@goforit64.fsnet.co.uk> wrote in message
news:kurious.1a0it4@physicsforums.com...
>
>
> How much energy does it take to change the polarization of a photon?

None

> Can a gravitational wave change the polarization of a photon?

No

Franz

John T Lowry

Jul28-04, 03:05 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\n\n"kurious" <alistair@goforit64.fsnet.co.uk> wrote in message\nnews:kurious.1a0it4@physicsforums.com...\n>\n>\n> How much energy does it take to change the polarization of a photon?\n> Can a gravitational wave change the polarization of a photon?\n>\n> ----------------------------------------------------------------------\n--\n> This post submitted through the LaTeX-enabled physicsforums.com\n> To view this post with LaTeX images:\n> http://www.physicsforums.com/showthread.php?t=36658#post266194\n\n\n\nYour questions are ill posed.\n\nQuantum objects don\'t have attributes, as such, beyond those used to\ndefine their essential natures. And a photon is the quantum object par\nexcellance. Quantum states are not to be associated with individual\nquantum objects, but rather with the preparation scheme from which they\nexit. In this sense one can indeed be assured that a photon issuing from\na particular optical equipment arrangement has say circular polarization\n(in that a second passage through an identical arrangement will pass all\nthose photons).\n\nIt\'s not fruitful to think about quantum experiments "changing"\nattributes of quantum objects. Those experiments are more like filters;\nsome of the initially prepared objects get through, others don\'t\n(according to the quantum amplitudes and the resulting probabilities).\nCertainly a photon is not going to be "forced" to change polarization\nstate by some physical influence. It\'s nothing like a planet forced to\nrevolve by gravitation with the sun, or even like a silver atom\ndeflected upwards (say) by an inhomogeneous vertical magnetic field. The\nimportant thing is to write down the detailed specifications of the\nexperiment you have in mind, then push a certain assumed initial state\nfor your ensemble of photons through it and see what the calculations\ngive you.\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.1a0it4@physicsforums.com...
>
>
> How much energy does it take to change the polarization of a photon?
> Can a gravitational wave change the polarization of a photon?
>
> ----------------------------------------------------------------------
--
> This post submitted through the LaTeX-enabled physicsforums.com
> To view this post with LaTeX images:
> http://www.physicsforums.com/showthread.php?t=36658#post266194

Your questions are ill posed.

Quantum objects don't have attributes, as such, beyond those used to
define their essential natures. And a photon is the quantum object par
excellance. Quantum states are not to be associated with individual
quantum objects, but rather with the preparation scheme from which they
exit. In this sense one can indeed be assured that a photon issuing from
a particular optical equipment arrangement has say circular polarization
(in that a second passage through an identical arrangement will pass all
those photons).

It's not fruitful to think about quantum experiments "changing"
attributes of quantum objects. Those experiments are more like filters;
some of the initially prepared objects get through, others don't
(according to the quantum amplitudes and the resulting probabilities).
Certainly a photon is not going to be "forced" to change polarization
state by some physical influence. It's nothing like a planet forced to
revolve by gravitation with the sun, or even like a silver atom
deflected upwards (say) by an inhomogeneous vertical magnetic field. The
important thing is to write down the detailed specifications of the
experiment you have in mind, then push a certain assumed initial state
for your ensemble of photons through it and see what the calculations
give you.

Franz Heymann

Jul29-04, 05:59 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"John T Lowry" <jlowry100@earthlink.net> wrote in message\nnews:w3SNc.1318\\$9Y6.102@newsread1.news.pas.earthlink.net...\n>\n>\n>\n> "kurious" <alistair@goforit64.fsnet.co.uk> wrote in message\n> news:kurious.1a0it4@physicsforums.com...\n> >\n> >\n> > How much energy does it take to change the polarization of a\nphoton?\n> > Can a gravitational wave change the polarization of a photon?\n> >\n>\n> --------------------------------------------------------------------\n--\n> --\n> > This post submitted through the LaTeX-enabled physicsforums.com\n> > To view this post with LaTeX images:\n> > http://www.physicsforums.com/showthread.php?t=36658#post266194\n>\n>\n>\n> Your questions are ill posed.\n>\n> Quantum objects don\'t have attributes, as such, beyond those used to\n> define their essential natures. And a photon is the quantum object\npar\n> excellance. Quantum states are not to be associated with individual\n> quantum objects, but rather with the preparation scheme from which\nthey\n> exit. In this sense one can indeed be assured that a photon issuing\nfrom\n> a particular optical equipment arrangement has say circular\npolarization\n> (in that a second passage through an identical arrangement will pass\nall\n> those photons).\n>\n> It\'s not fruitful to think about quantum experiments "changing"\n> attributes of quantum objects. Those experiments are more like\nfilters;\n> some of the initially prepared objects get through, others don\'t\n> (according to the quantum amplitudes and the resulting\nprobabilities).\n> Certainly a photon is not going to be "forced" to change\npolarization\n> state by some physical influence. It\'s nothing like a planet forced\nto\n> revolve by gravitation with the sun, or even like a silver atom\n> deflected upwards (say) by an inhomogeneous vertical magnetic field.\nThe\n> important thing is to write down the detailed specifications of the\n> experiment you have in mind, then push a certain assumed initial\nstate\n> for your ensemble of photons through it and see what the\ncalculations\n> give you.\n\nHave you forgotten that the spin state of a particle may be changed in\na scattering process?\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>"John T Lowry" <jlowry100@earthlink.net> wrote in message
news:w3SNc.1318$9Y6.102@newsread1.news.pas.earthlink.net...
>
>
>
> "kurious" <alistair@goforit64.fsnet.co.uk> wrote in message
> news:kurious.1a0it4@physicsforums.com...
> >
> >
> > How much energy does it take to change the polarization of a
photon?
> > Can a gravitational wave change the polarization of a photon?
> >
>
> --------------------------------------------------------------------
--
> --
> > This post submitted through the LaTeX-enabled physicsforums.com
> > To view this post with LaTeX images:
> > http://www.physicsforums.com/showthread.php?t=36658#post266194
>
>
>
> Your questions are ill posed.
>
> Quantum objects don't have attributes, as such, beyond those used to
> define their essential natures. And a photon is the quantum object
par
> excellance. Quantum states are not to be associated with individual
> quantum objects, but rather with the preparation scheme from which
they
> exit. In this sense one can indeed be assured that a photon issuing
from
> a particular optical equipment arrangement has say circular
polarization
> (in that a second passage through an identical arrangement will pass
all
> those photons).
>
> It's not fruitful to think about quantum experiments "changing"
> attributes of quantum objects. Those experiments are more like
filters;
> some of the initially prepared objects get through, others don't
> (according to the quantum amplitudes and the resulting
probabilities).
> Certainly a photon is not going to be "forced" to change
polarization
> state by some physical influence. It's nothing like a planet forced
to
> revolve by gravitation with the sun, or even like a silver atom
> deflected upwards (say) by an inhomogeneous vertical magnetic field.
The
> important thing is to write down the detailed specifications of the
> experiment you have in mind, then push a certain assumed initial
state
> for your ensemble of photons through it and see what the
calculations
> give you.

Have you forgotten that the spin state of a particle may be changed in
a scattering process?

Franz

John T Lowry

Jul29-04, 08:33 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"Franz Heymann" <notfranz.heymann@btopenworld.com> wrote in message\nnews:ce95dm\\$rem\\$1@sparta.btinternet.com...\n>\n>\n>\n> "John T Lowry" <jlowry100@earthlink.net> wrote in message\n> news:w3SNc.1318\\$9Y6.102@newsread1.news.pas.earthlink.net...\n> >\n> >\n> >\n> > "kurious" <alistair@goforit64.fsnet.co.uk> wrote in message\n> > news:kurious.1a0it4@physicsforums.com...\n> > >\n> > >\n> > > How much energy does it take to change the polarization of a\n> photon?\n> > > Can a gravitational wave change the polarization of a photon?\n> > >\n> >\n> > --------------------------------------------------------------------\n> --\n> > --\n> > > This post submitted through the LaTeX-enabled physicsforums.com\n> > > To view this post with LaTeX images:\n> > > http://www.physicsforums.com/showthread.php?t=36658#post266194\n> >\n> >\n> >\n> > Your questions are ill posed.\n> >\n> > Quantum objects don\'t have attributes, as such, beyond those used to\n> > define their essential natures. And a photon is the quantum object\n> par\n> > excellance. Quantum states are not to be associated with individual\n> > quantum objects, but rather with the preparation scheme from which\n> they\n> > exit. In this sense one can indeed be assured that a photon issuing\n> from\n> > a particular optical equipment arrangement has say circular\n> polarization\n> > (in that a second passage through an identical arrangement will pass\n> all\n> > those photons).\n> >\n> > It\'s not fruitful to think about quantum experiments "changing"\n> > attributes of quantum objects. Those experiments are more like\n> filters;\n> > some of the initially prepared objects get through, others don\'t\n> > (according to the quantum amplitudes and the resulting\n> probabilities).\n> > Certainly a photon is not going to be "forced" to change\n> polarization\n> > state by some physical influence. It\'s nothing like a planet forced\n> to\n> > revolve by gravitation with the sun, or even like a silver atom\n> > deflected upwards (say) by an inhomogeneous vertical magnetic field.\n> The\n> > important thing is to write down the detailed specifications of the\n> > experiment you have in mind, then push a certain assumed initial\n> state\n> > for your ensemble of photons through it and see what the\n> calculations\n> > give you.\n>\n> Have you forgotten that the spin state of a particle may be changed in\n> a scattering process?\n>\n> Franz\n>\n\nPhoton spin flips? Sounds good, but I don\'t have such a firm grasp on\nthose slippery photons. Seems to me that annihilation (absorption) of\nthe incoming photon and creation (emission) of an outgoing photon is the\nbetter picture.\n\nJohn.\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:ce95dm$rem$1@sparta.btinternet.com...
>
>
>
> "John T Lowry" <jlowry100@earthlink.net> wrote in message
> news:w3SNc.1318$9Y6.102@newsread1.news.pas.earthlink.net...
> >
> >
> >
> > "kurious" <alistair@goforit64.fsnet.co.uk> wrote in message
> > news:kurious.1a0it4@physicsforums.com...
> > >
> > >
> > > How much energy does it take to change the polarization of a
> photon?
> > > Can a gravitational wave change the polarization of a photon?
> > >
> >
> > --------------------------------------------------------------------
> --
> > --
> > > This post submitted through the LaTeX-enabled physicsforums.com
> > > To view this post with LaTeX images:
> > > http://www.physicsforums.com/showthread.php?t=36658#post266194
> >
> >
> >
> > Your questions are ill posed.
> >
> > Quantum objects don't have attributes, as such, beyond those used to
> > define their essential natures. And a photon is the quantum object
> par
> > excellance. Quantum states are not to be associated with individual
> > quantum objects, but rather with the preparation scheme from which
> they
> > exit. In this sense one can indeed be assured that a photon issuing
> from
> > a particular optical equipment arrangement has say circular
> polarization
> > (in that a second passage through an identical arrangement will pass
> all
> > those photons).
> >
> > It's not fruitful to think about quantum experiments "changing"
> > attributes of quantum objects. Those experiments are more like
> filters;
> > some of the initially prepared objects get through, others don't
> > (according to the quantum amplitudes and the resulting
> probabilities).
> > Certainly a photon is not going to be "forced" to change
> polarization
> > state by some physical influence. It's nothing like a planet forced
> to
> > revolve by gravitation with the sun, or even like a silver atom
> > deflected upwards (say) by an inhomogeneous vertical magnetic field.
> The
> > important thing is to write down the detailed specifications of the
> > experiment you have in mind, then push a certain assumed initial
> state
> > for your ensemble of photons through it and see what the
> calculations
> > give you.
>
> Have you forgotten that the spin state of a particle may be changed in
> a scattering process?
>
> Franz
>

Photon spin flips? Sounds good, but I don't have such a firm grasp on
those slippery photons. Seems to me that annihilation (absorption) of
the incoming photon and creation (emission) of an outgoing photon is the
better picture.

John.

p.kinsler@imperial.ac.uk

Aug12-04, 09:29 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\nJohn T Lowry <jlowry100@earthlink.net> wrote:\n> "Franz Heymann" <notfranz.heymann@btopenworld.com> wrote:\n> > [...]\n> > Have you forgotten that the spin state of a particle may be changed in\n> > a scattering process?\n\n> Photon spin flips? Sounds good, but I don\'t have such a firm grasp on\n> those slippery photons. Seems to me that annihilation (absorption) of\n> the incoming photon and creation (emission) of an outgoing photon is the\n> better picture.\n\nI agree. It may indeed be possible to invent some kind of crazy\nfield modes which have an incoming and outgoing part with differing\npolarizations; but it\'s unlikely that they\'d be easy to calculate\nwith. Also, given there may be many excitations in a field mode,\nin all kinds of wierd superpositions, it would be difficult to\nsensibly decide [1] how to say which incoming excitations were\nscattered and which weren\'t.\n\n[1] Let alone the fact that it\'d be a decision without any physical\nmeaning; although it might help some people in an intuitive sense.\n\nAh, spr talking about photons. Maybe I\'ll ask that nice Baez fellow\nabout the arrow of time...\n\n--\n---------------------------------+---------------------------------\nDr. Paul Kinsler\nBlackett Laboratory (QOLS) (ph) +44-20-759-47520 (fax) 47714\nImperial College London, Dr.Paul.Kinsler@physics.org\nSW7 2BW, United Kingdom. http://www.qols.ph.ic.ac.uk/~kinsle/\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 <jlowry100@earthlink.net> wrote:
> "Franz Heymann" <notfranz.heymann@btopenworld.com> wrote:
> > [...]
> > Have you forgotten that the spin state of a particle may be changed in
> > a scattering process?

> Photon spin flips? Sounds good, but I don't have such a firm grasp on
> those slippery photons. Seems to me that annihilation (absorption) of
> the incoming photon and creation (emission) of an outgoing photon is the
> better picture.

I agree. It may indeed be possible to invent some kind of crazy
field modes which have an incoming and outgoing part with differing
polarizations; but it's unlikely that they'd be easy to calculate
with. Also, given there may be many excitations in a field mode,
in all kinds of wierd superpositions, it would be difficult to
sensibly decide [1] how to say which incoming excitations were
scattered and which weren't.

[1] Let alone the fact that it'd be a decision without any physical
meaning; although it might help some people in an intuitive sense.

Ah, spr talking about photons. Maybe I'll ask that nice Baez fellow
about the arrow of time...

--
---------------------------------+---------------------------------
Dr. Paul Kinsler
Blackett Laboratory (QOLS) (ph) +44-20-759-47520 (fax) 47714
Imperial College London, Dr.Paul.Kinsler@physics.org
SW7 2BW, United Kingdom. http://www.qols.ph.ic.ac.uk/~kinsle/