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Science Forum Index » Physics - Electromagnetic Forum » ?????Virtual Photons
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| turtle |
Posted: Tue Oct 23, 2007 3:42 pm |
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Apparently since no one in the group has come up with the wavelength
or energy level of a virtual photon, I must assume that the concept is
highly theoretical.
skeptical turtle |
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| Vince Morgan |
Posted: Tue Oct 23, 2007 8:26 pm |
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Perhaps, but that is a very narrow criteria for a firm descision one would
think
"turtle" <turtlezero@webtv.net> wrote in message
news:1193172178.953014.40840@t8g2000prg.googlegroups.com...
Quote: Apparently since no one in the group has come up with the wavelength
or energy level of a virtual photon, I must assume that the concept is
highly theoretical.
skeptical turtle
VM |
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| RP |
Posted: Tue Oct 23, 2007 10:23 pm |
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On Oct 23, 3:42 pm, turtle <turtlez...@webtv.net> wrote:
Quote: Apparently since no one in the group has come up with the wavelength
or energy level of a virtual photon, I must assume that the concept is
highly theoretical.
skeptical turtle
virtual
virtual (vűr´chˇ-el) adjective
1.Existing or resulting in essence or effect though not in actual
fact, form, or name: the virtual extinction of the buffalo.
2.Existing in the mind, especially as a product of the imagination.
Used in literary criticism of text.
[Middle English virtuall, effective, from Medieval Latin virtuâlis,
from Latin virtús, excellence. See virtue.]
- vir´tual´ity (-ŕl´î-tę) noun
Excerpted from The American Heritage® Dictionary of the English
Language, Third Edition © 1996 by Houghton Mifflin Company.
Electronic version licensed from INSO Corporation; further
reproduction and distribution in accordance with the Copyright Law of
the United States. All rights reserved. |
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| turtle |
Posted: Wed Oct 24, 2007 4:24 am |
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RP wrote:
Quote: On Oct 23, 3:42 pm, turtle <turtlez...@webtv.net> wrote:
Apparently since no one in the group has come up with the wavelength
or energy level of a virtual photon, I must assume that the concept is
highly theoretical.
skeptical turtle
virtual
virtual (vűr´chˇ-el) adjective
1.Existing or resulting in essence or effect though not in actual
fact, form, or name: the virtual extinction of the buffalo.
2.Existing in the mind, especially as a product of the imagination.
Used in literary criticism of text.
[Middle English virtuall, effective, from Medieval Latin virtuâlis,
from Latin virtús, excellence. See virtue.]
- vir´tual´ity (-ŕl´î-tę) noun
Excerpted from The American Heritage® Dictionary of the English
Language, Third Edition © 1996 by Houghton Mifflin Company.
Electronic version licensed from INSO Corporation; further
reproduction and distribution in accordance with the Copyright Law of
the United States. All rights reserved.
My next question would be----what is the virtual wavelength and
virtual energy of a virtual photon?
turtle |
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| turtle |
Posted: Wed Oct 24, 2007 4:26 am |
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RP wrote:
Quote: On Oct 23, 3:42 pm, turtle <turtlez...@webtv.net> wrote:
Apparently since no one in the group has come up with the wavelength
or energy level of a virtual photon, I must assume that the concept is
highly theoretical.
skeptical turtle
virtual
virtual (vűr´chˇ-el) adjective
1.Existing or resulting in essence or effect though not in actual
fact, form, or name: the virtual extinction of the buffalo.
2.Existing in the mind, especially as a product of the imagination.
Used in literary criticism of text.
[Middle English virtuall, effective, from Medieval Latin virtuâlis,
from Latin virtús, excellence. See virtue.]
- vir´tual´ity (-ŕl´î-tę) noun
Excerpted from The American Heritage® Dictionary of the English
Language, Third Edition © 1996 by Houghton Mifflin Company.
Electronic version licensed from INSO Corporation; further
reproduction and distribution in accordance with the Copyright Law of
the United States. All rights reserved.
My next question would be----what is the virtual wavelength and
virtual energy of a virtual photon?
turtle |
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| RP |
Posted: Wed Oct 24, 2007 5:09 pm |
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On Oct 24, 4:26 am, turtle <turtlez...@webtv.net> wrote:
Quote: RP wrote:
On Oct 23, 3:42 pm, turtle <turtlez...@webtv.net> wrote:
Apparently since no one in the group has come up with the wavelength
or energy level of a virtual photon, I must assume that the concept is
highly theoretical.
skeptical turtle
virtual
virtual (vűr´chˇ-el) adjective
1.Existing or resulting in essence or effect though not in actual
fact, form, or name: the virtual extinction of the buffalo.
2.Existing in the mind, especially as a product of the imagination.
Used in literary criticism of text.
[Middle English virtuall, effective, from Medieval Latin virtuâlis,
from Latin virtús, excellence. See virtue.]
- vir´tual´ity (-ŕl´î-tę) noun
Excerpted from The American Heritage® Dictionary of the English
Language, Third Edition © 1996 by Houghton Mifflin Company.
Electronic version licensed from INSO Corporation; further
reproduction and distribution in accordance with the Copyright Law of
the United States. All rights reserved.
My next question would be----what is the virtual wavelength and
virtual energy of a virtual photon?
turtle- Hide quoted text -
- Show quoted text -
A better question is "what the heck IS a photon anyway"?
http://www.math.ucr.edu/home/baez/photon/schmoton.htm
What isn't discussed in that article is the fact that in the context
of Minkowski space-time (special relativity) there are no waves, light
describes a null geodesic, i.e. zero displacement in space-time.
Special relativity and photon theory are diametrically opposed to one
another. |
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| Autymn D. C. |
Posted: Thu Oct 25, 2007 7:46 am |
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On Oct 23, 6:26 pm, "Vince Morgan" <vinharAtHereoptusnet.com.au>
wrote:
Quote: Perhaps, but that is a very narrow criteria for a firm descision one would
think
criteriňn
decision |
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| Guest |
Posted: Thu Oct 25, 2007 5:01 pm |
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RP <no_mail_no_spam@yahoo.com> wrote:
Quote: Special relativity and photon theory are diametrically opposed to one
another.
Most passing quantum opticians would model photons as being excitations
of EM field modes, and those modes would be solutions of Maxwells
equations. Are Maxwells equations not sufficiently relativistic for you?
Claiming a /diametric opposition/ would seem to be going a little too
far, don't you think?
--
---------------------------------+---------------------------------
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/ |
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| RP |
Posted: Thu Oct 25, 2007 10:19 pm |
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On Oct 25, 5:01 pm, p.kins...@ic.ac.uk wrote:
Quote: RP <no_mail_no_s...@yahoo.com> wrote:
Special relativity and photon theory are diametrically opposed to one
another.
Most passing quantum opticians would model photons as being excitations
of EM field modes, and those modes would be solutions of Maxwells
equations. Are Maxwells equations not sufficiently relativistic for you?
Claiming a /diametric opposition/ would seem to be going a little too
far, don't you think?
--
---------------------------------+---------------------------------
Dr. Paul Kinsler
Blackett Laboratory (QOLS) (ph) +44-20-759-47520 (fax) 47714
Imperial College London, Dr.Paul.Kins...@physics.org
SW7 2BW, United Kingdom. http://www.qols.ph.ic.ac.uk/~kinsle/
Regardless of how photons are modeled, anything regarded to exist in
between is philosophy. It cannot be measured. The beauty of
Minkowski's formulation is that the "in between" is zeroed out, and
becomes superflous. Space and time cease to exist as such, and are
replace with space-time, the latter of which isn't an aether in which
things exist and move (as was Newton's absolute space), but rather
it's the very substance of those things and of thier motions.
The interaction of electrons (light) requires no medium, which in turn
implies no mediation. What are photons but mediators of light? How is
this not diametric opposition?
If the space-time displacement between interacting electrons is zero,
then where is there room for photons in between, or anything else for
that matter?
Here's a a little something snipped from Baez's article:
What binds us to space-time is our rest mass, which prevents us from
flying at the speed of light, when time stops and space loses meaning.
In a world of light there are neither points nor moments of time;
beings woven from light would live "nowhere" and "nowhen"; only poetry
and mathematics are capable of speaking meaningfully about such
things. - Yuri Manin |
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| HapticZ |
Posted: Sun Oct 28, 2007 3:21 pm |
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a virtual photon?
perhaps one type that is pure of essence and intent?
perhaps an energy void of error or concept?
perhaps of realm yet unknown to our febrile concept of the universe?
"turtle" <turtlezero@webtv.net> wrote in message
news:1193172178.953014.40840@t8g2000prg.googlegroups.com...
Quote: Apparently since no one in the group has come up with the wavelength
or energy level of a virtual photon, I must assume that the concept is
highly theoretical.
skeptical turtle
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| Chris |
Posted: Tue Oct 30, 2007 3:13 am |
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If you have an antenna the induction field is virtual photons.
"HapticZ" <hapticz@sbcglobal.net> wrote in message
news:0b6Vi.61061$Um6.4013@newssvr12.news.prodigy.net...
Quote: a virtual photon?
perhaps one type that is pure of essence and intent?
perhaps an energy void of error or concept?
perhaps of realm yet unknown to our febrile concept of the universe?
"turtle" <turtlezero@webtv.net> wrote in message
news:1193172178.953014.40840@t8g2000prg.googlegroups.com...
Apparently since no one in the group has come up with the wavelength
or energy level of a virtual photon, I must assume that the concept is
highly theoretical.
skeptical turtle
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| Thomas |
Posted: Tue Oct 30, 2007 2:26 pm |
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When you speak of (single) photons, you can't speak of energies or
wavelengths. The quantum theory (and yes, a photon is a quantum) forbids
it. It's hard to accept this. Very easy speaking: If you know the exact
time the photon comes in (because you think of a tiny drop flying
around), the energy will be very uncertain (Heissenberg principle). The
result is: the photon is no wave with one wavelength, but a wavepacket
with a lot of wavelengths.
I'm not too deep into virtual things. But if it is called virtual, it
means, you can't detect it but theory uses it. Whatever it is what really
happens, the effects wich result from assuming a virtual photon are
measurable.
Sorry, dude.
On Tue, 23 Oct 2007 13:42:58 -0700 you wrote turtle:
Quote: Apparently since no one in the group has come up with the wavelength or
energy level of a virtual photon, I must assume that the concept is
highly theoretical.
skeptical turtle |
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| Guest |
Posted: Wed Oct 31, 2007 11:29 am |
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Thomas <not@valid.org> wrote:
Quote: When you speak of (single) photons, you can't speak of energies or
wavelengths.
Yes, you can. You can define photons to be (single) excitations
of a quantized EM field mode; these modes are solutions to
the classical Maxwell's equations. If, for example, the modes
are those in an optical cavity (resonator), then they have a
specific energy and a specifc wavelength.
This is a model used by the quantum optics subfield of physics;
it produces a wide variety of useful and testable predictions.
--
---------------------------------+---------------------------------
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/ |
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| Darwin123 |
Posted: Wed Nov 14, 2007 2:01 am |
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On Oct 24, 4:24 am, turtle <turtlez...@webtv.net> wrote:
Quote: RP wrote:
On Oct 23, 3:42 pm, turtle <turtlez...@webtv.net> wrote:
Apparently since no one in the group has come up with the wavelength
or energy level of a virtual photon, I must assume that the concept is
highly theoretical.
My next question would be----what is the virtual wavelength and
virtual energy of a virtual photon?
turtle
Physical quantities don't depend on the energy of any one virtual
photon, but have to be calculated using an integral over the virtual
photon energy.
There is a statistical distribution of virtual energies,
characterized by a mathematical function called the propagator, or
Green's function. The virtual energy becomes an integration variable
when calculating the cross-matrix.
I think another way to look at it is that there is an uncertainty
in the number of virtual photons. The energies of all the photons have
to add up to the difference in energy between the initial and final
states, but there can be any number of virtual photons from 1 to
infinity. Therefore, the energy of each virtual photon is uncertain.
I think of it this way. Virtual photons are an artifact of forcing
a particle picture on a system which is mostly wave-like (or field-
like). |
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| Darwin123 |
Posted: Thu Nov 15, 2007 8:24 am |
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On Oct 31, 11:29 am, p.kins...@ic.ac.uk wrote:
Quote: Thomas <n...@valid.org> wrote:
When you speak of (single) photons, you can't speak of energies or
wavelengths.
Yes, you can. You can define photons to be (single) excitations
of a quantized EM field mode; these modes are solutions to
the classical Maxwell's equations. If, for example, the modes
are those in an optical cavity (resonator), then they have a
specific energy and a specifc wavelength.
He may have been right concerning virtual photons. I don't think
the number, energy, or wavelength of virtual photons are good quantum
numbers. Remember the uncertainty relations related to photon
emission. The energy bandwidth of emitted radiation times the lifetime
of the excited state is equal or greater than Planks constant. The
energy bandwidth of the emitted photon corresponds to the uncertainty
in energy of the virtual photons.
Consider the absorption of a single real photon by an atom,
resulting in a transition of energy E_t. The Feynmann diagram
associated with the dipole interaction shows a straightforward
interaction, with no virtual photons. The diagram associated with the
quadropole interaction shows a transition to a still higher
intermediate state, involving two virtual photons with an uncertain
energy. The diagram associated with an octopole interaction involves
four virtual photons... There is more than one Feynmann diagram
necessary to describe a real transition precisely because there is an
uncertainty in the energy of a virtual photons involved. There is also
an uncertainty in the number of virtual photons involved. Why would
you need perturbation theory if virtual photons had a precisely
determined energy? |
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