View Full Version : Anti-phonon for Cooling
Curious
May12-04, 05:05 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>\n\nIs it possible to use anti-phonons for cooling the environment?\n\nThe quantum of heat is the phonon. An "anti-phonon" is simply a phonon\nwhose phase is reversed. Two phonons of opposite phases would cancel\neach other. Right?\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>Is it possible to use anti-phonons for cooling the environment?
The quantum of heat is the phonon. An "anti-phonon" is simply a phonon
whose phase is reversed. Two phonons of opposite phases would cancel
each other. Right?
Uncle Al
May12-04, 05:28 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>Curious wrote:\n>\n> Is it possible to use anti-phonons for cooling the environment?\n>\n> The quantum of heat is the phonon. An "anti-phonon" is simply a phonon\n> whose phase is reversed. Two phonons of opposite phases would cancel\n> each other. Right?\n\nConservation of energy. A phonon is a quantized lattice vibration.\nAnnihalation of anti-phased phonons, if such a thing had meaning,\ndoesn\'t destroy the total energy. Positronium collapsing is an\nenergetic process - two 511 keV photons (and other paths depending on\ninitial spin state). A nulled interferometer (e.g., LIGO) doesn\'t\ndestroy its lasers\' energy, it redistributes it.\n\n--\nUncle Al\nhttp://www.mazepath.com/uncleal/qz.pdf\nhttp://www.mazepath.com/uncleal/eotvos.htm\n(Do something naughty to 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>Curious wrote:
>
> Is it possible to use anti-phonons for cooling the environment?
>
> The quantum of heat is the phonon. An "anti-phonon" is simply a phonon
> whose phase is reversed. Two phonons of opposite phases would cancel
> each other. Right?
Conservation of energy. A phonon is a quantized lattice vibration.
Annihalation of anti-phased phonons, if such a thing had meaning,
doesn't destroy the total energy. Positronium collapsing is an
energetic process - two 511 keV photons (and other paths depending on
initial spin state). A nulled interferometer (e.g., LIGO) doesn't
destroy its lasers' energy, it redistributes it.
--
Uncle Al
http://www.mazepath.com/uncleal/qz.pdf
http://www.mazepath.com/uncleal/eotvos.htm
(Do something naughty to physics)
Jacques Lavau
May14-04, 04:07 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>Curious a écrit :\n\n> Is it possible to use anti-phonons for cooling the environment?\n>\n> The quantum of heat is the phonon. An "anti-phonon" is simply a phonon\n> whose phase is reversed. Two phonons of opposite phases would cancel\n> each other. Right?\n\nWell ! How do you produce and handle them ?\nIt is easy to consider and write something about phonons.\nIt is quite another damn thing to master, produce, direct them\nindividually, with a frequency, a phase, a direction, so on...\n\nAre you a Maxwell demon, you ?\nHow do you consider the life-time of a phonon in a crystal, between\ncreation and annihilation ? What do you consider as a measuring device,\nin order to copy an existing phonon, and to emit the right antiphonon ?\n\nWell ! A pretty good troll, indeed !\n\n--\nLa science se distingue de tous les autres modes de transmission des\nconnaissances, par une croyance de base : nous croyons que les experts\nsont faillibles, que les connaissances transmises peuvent contenir\ntoutes sortes de fables et déerreurs, et qu=92il faut prendre la peine de\nvérifier, par des expériences.\n-- Jacques Lavau (retirer les anti et les spam pour le courriel)\nhttp://perso.club-internet.fr/lavaujac/\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>Curious a écrit :
> Is it possible to use anti-phonons for cooling the environment?
>
> The quantum of heat is the phonon. An "anti-phonon" is simply a phonon
> whose phase is reversed. Two phonons of opposite phases would cancel
> each other. Right?
Well ! How do you produce and handle them ?
It is easy to consider and write something about phonons.
It is quite another damn thing to master, produce, direct them
individually, with a frequency, a phase, a direction, so on...
Are you a Maxwell demon, you ?
How do you consider the life-time of a phonon in a crystal, between
creation and annihilation ? What do you consider as a measuring device,
in order to copy an existing phonon, and to emit the right antiphonon ?
Well ! A pretty good troll, indeed !
--
La science se distingue de tous les autres modes de transmission des
connaissances, par une croyance de base : nous croyons que les experts
sont faillibles, que les connaissances transmises peuvent contenir
toutes sortes de fables et déerreurs, et qu=92il faut prendre la peine de
vérifier, par des \expériences.
-- Jacques Lavau (retirer les anti et les spam pour le courriel)
http://perso.club-internet.fr/lavaujac/
Igor Khavkine
May14-04, 04:07 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>curious11112001@yahoo.com (Curious) wrote in message news:<34a4f456.0405111319.40908764@posting.google. com>...\n> Is it possible to use anti-phonons for cooling the environment?\n>\n> The quantum of heat is the phonon. An "anti-phonon" is simply a phonon\n> whose phase is reversed. Two phonons of opposite phases would cancel\n> each other. Right?\n\nAs far as I know, there is no quantum of heat. Heat or temperature\nare statistical phenomena due to thermal (read more or less random)\nmotion of a large number of particles.\n\nPhonons are quantums of lattice vibrations and are their own anti-particles,\njust as photons are also their own anti-particles.\n\nPhonons are indeed waves, and at least classically it is possible to\ncancel one wave with a wave with another wave of the same amplitude\nbut out of phase by pi (or different by a factor of -1). However, this\nproperty is fairly useless for the purposes of cooling. Even if you were\nable to cancel out all phonon noice thermal motion of electrons and spins\nwould still be present. Besides, trying to remove all phonon noise\nusing descructive interference is like trying to dim the Sun by sending\nspecially modulated photons at it. It\'s not going to work.\n\nHope this helps.\n\nIgor\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>curious11112001@yahoo.com (Curious) wrote in message news:<34a4f456.0405111319.40908764@posting.google.com>...
> Is it possible to use anti-phonons for cooling the environment?
>
> The quantum of heat is the phonon. An "anti-phonon" is simply a phonon
> whose phase is reversed. Two phonons of opposite phases would cancel
> each other. Right?
As far as I know, there is no quantum of heat. Heat or temperature
are statistical phenomena due to thermal (read more or less random)
motion of a large number of particles.
Phonons are quantums of lattice vibrations and are their own anti-particles,
just as photons are also their own anti-particles.
Phonons are indeed waves, and at least classically it is possible to
cancel one wave with a wave with another wave of the same amplitude
but out of phase by \pi (or different by a factor of -1). However, this
property is fairly useless for the purposes of cooling. Even if you were
able to cancel out all phonon noice thermal motion of electrons and spins
would still be present. Besides, trying to remove all phonon noise
using descructive interference is like trying to dim the Sun by sending
specially modulated photons at it. It's not going to work.
Hope this helps.
Igor
<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>\nk_igor_k@lycos.com (Igor Khavkine) wrote in message news:<f1ac2e6e.0405120736.7312742b@posting.google. com>...\n> curious11112001@yahoo.com (Curious) wrote in message news:<34a4f456.0405111319.40908764@posting.google. com>...\n> > Is it possible to use anti-phonons for cooling the environment?\n> >\nsnip\n>> would still be present. Besides, trying to remove all phonon noise\n> using descructive interference is like trying to dim the Sun by sending\n> specially modulated photons at it. It\'s not going to work.\n>\n> Hope this helps.\n>\n> Igor\n\nOK, practically no, but not quite as stupid as it sounds at first.\nActually, you can cool things by shining light at them - optical\nmolasses is quite a common technique.\n\nBut also, if the object you are trying to cool has been set up with a\npopulation inversion of states which can EM couple, it is a laser.\nFire one photon in, get two photons out, target loses net energy.\n\nIn a crystal lattice at low temperature, the phonon spectrum can show\ndistinct spectra. And I seem to remember reading some experiment that\nshowed population inversions in phonon states, although I don\'t have a\nreference to hand. They were suggesting that their device could be\nused as a "phonon laser" to probe crystal lattice defects at low\ntemperatures\n\nCertainly experiments have been performed that have demonstrated\nphonon ballistic transport (i.e. mean-free path of phonon > size of\ntest-chip) in GaAs/AlGaAs structures at 30 mK temperatures, which\nmeans that phonon two-slit diffraction experiments are within reach\n[yes, I know ballistic doesn\'t mean phase-coherent, phase-coherent\nincludes low-scattering angle events, but it shows it isn\'t\nimpossible]\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>k_{igor_k}@lycos.com (Igor Khavkine) wrote in message news:<f1ac2e6e.0405120736.7312742b@posting.google.com>...
> curious11112001@yahoo.com (Curious) wrote in message news:<34a4f456.0405111319.40908764@posting.google.com>...
> > Is it possible to use anti-phonons for cooling the environment?
> >
snip
>> would still be present. Besides, trying to remove all phonon noise
> using descructive interference is like trying to dim the Sun by sending
> specially modulated photons at it. It's not going to work.
>
> Hope this helps.
>
> Igor
OK, practically no, but not quite as stupid as it sounds at first.
Actually, you can cool things by shining light at them - optical
molasses is quite a common technique.
But also, if the object you are trying to cool has been set up with a
population inversion of states which can EM couple, it is a laser.
Fire one photon in, get two photons out, target loses net energy.
In a crystal lattice at low temperature, the phonon spectrum can show
distinct spectra. And I seem to remember reading some experiment that
showed population inversions in phonon states, although I don't have a
reference to hand. They were suggesting that their device could be
used as a "phonon laser" to probe crystal lattice defects at low
temperatures
Certainly experiments have been performed that have demonstrated
phonon ballistic transport (i.e. mean-free path of phonon > size of
test-chip) in GaAs/AlGaAs structures at 30 mK temperatures, which
means that phonon two-slit diffraction experiments are within reach
[yes, I know ballistic doesn't mean phase-coherent, phase-coherent
includes low-scattering angle events, but it shows it isn't
impossible]
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