Virtual particle question
Virtual particle question
Hello,Im doing research on virtual particles and was wondering if their are different views on virtual particles,Are they real or exist or are they not real?
- neufer
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Re: Virtual particle question
Quantum electrodynamics is our most accurate verified physical theory.outlaw wrote:
Hello,Im doing research on virtual particles and was wondering if their are different views on virtual particles,
Are they real or exist or are they not real?
Quantum electrodynamics is based upon the assumption of the temporary existence of virtual particles.
What more can I say?
Art Neuendorffer
Re: Virtual particle question
I was reading that the casmir effect can be explained without virtual particles.neufer wrote:Quantum electrodynamics is our most accurate verified physical theory.outlaw wrote:
Hello,Im doing research on virtual particles and was wondering if their are different views on virtual particles,
Are they real or exist or are they not real?
Quantum electrodynamics is based upon the assumption of the temporary existence of virtual particles.
What more can I say?
Re: Virtual particle question
Info on virtual particles here. Hope this helps.
A closed mouth gathers no foot.
Re: Virtual particle question
As far as I can remember, Stephen Hawking's theory that black holes are going to evaporate sooner or later is built on the idea of virtual particles. The idea is that virtual particles always "pop out of the vaccuum" in pairs, one positively charged, one negatively charged. They instantly meet and annihilate each other, which is what happens when, say, an electron and a positron meet. But in the case of the virtual particles near a black hole, the idea is that one of the virtual particles is sucked into the black hole and annihilated before it can annihilate its "virtual particle brother". The surviving virtual particle therefore has no "partner" that is going to annihilate it, and since it doesn't fall into the black hole like it mate (which is purely due to chance), it is going to change from a virtual particle into a real particle. But this change from "virtual" to "real" takes energy, and according to Hawking, this energy can only be taken from the black hole.
Over time, more and more virtual particle pair are going to "pop up" near the black hole in such a position that one particle is going to fall into the black hole and be annihilated, and the other one will become real by "stealing energy" from the black hole. Eventually, the black hole is going to be sufficiently drained of energy by giving "life" to virtual particles that it is going to evaporate.
Ann
Over time, more and more virtual particle pair are going to "pop up" near the black hole in such a position that one particle is going to fall into the black hole and be annihilated, and the other one will become real by "stealing energy" from the black hole. Eventually, the black hole is going to be sufficiently drained of energy by giving "life" to virtual particles that it is going to evaporate.
Ann
Last edited by Ann on Wed May 18, 2011 5:39 pm, edited 1 time in total.
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- neufer
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Re: Virtual particle question
Virtual particles were not conceived of after the fact in order to explain an already observed Casimir effect.outlaw wrote:
I was reading that the casmir effect can be explained without virtual particles.
Rather, the yet to be observed Casimir effect was predicted to exist (and even
to be of a very specific magnitude) as a necessary consequence of virtual particles.
Phlogiston, aether and the like were once interesting (perhaps even useful) concepts
that have since been clearly proven not to exist.
Virtual particles constitute a very interesting (and extremely useful) concept
and have yet to be proved not to exist.
Art Neuendorffer
Re: Virtual particle question
neufer wrote:Virtual particles were not conceived of after the fact in order to explain an already observed Casimir effect.outlaw wrote:I was reading that the casmir effect can be explained without virtual particles.
[b]Casimir effect[/b] wrote:… Thus it can be interpreted without any reference to the zero-point energy (vacuum energy) or virtual particles of quantum fields.•
- Casimir effect and the quantum vacuum - RL Jaffe
- Physical Review D 72 020301 (July 2005) DOI: 10.1103/PhysRevD.72.021301
arXiv.org > hep-th > arXiv:hep-th/0503158 > 21 Mar 2005
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
Re: Virtual particle question
I also read that a non thing can travel faster than light such as a shadow?
- Chris Peterson
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Re: Virtual particle question
Of course. Even physical things can travel faster than light, and do so commonly. Indeed, physical things can even travel faster than c under special cases where no information is transmitted at greater than c.outlaw wrote:I also read that a non thing can travel faster than light such as a shadow?
Chris
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Re: Virtual particle question
I know that when something travels faster than light it has to deal with time travel backwards in the past and causality,do these things such as shadows travel into the past?
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Re: Virtual particle question
To be clear, it isn't traveling faster than light that is an issue, it is traveling faster than c. The two are not the same. Nothing that travels faster than c does so in a way that results in the transmission of information at faster than c, and therefore there is no backward time travel or problem with causality.outlaw wrote:I know that when something travels faster than light it has to deal with time travel backwards in the past and causality,do these things such as shadows travel into the past?
Chris
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- neufer
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Re: Virtual particle question
A shadow can transmit information and hence canNOT travel faster than c.Chris Peterson wrote:Of course. Even physical things can travel faster than light, and do so commonly. Indeed, physical things can even travel faster than c under special cases where no information is transmitted at greater than c.outlaw wrote:
I also read that a non thing can travel faster than light such as a shadow?
(A shadow travels at exactly the speed of light by definition.)
Art Neuendorffer
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Re: Virtual particle question
Yes, depending on how you define "shadow". But I think that the question is not really about shadows, but about certain non-physical projective phenomena (I believe we discussed the intersection of a closing scissors on this forum a few years ago), so I didn't want to get bogged down in the details of shadows specifically. (FWIW, a shadow carries information from the thing projecting the shadow, but it doesn't carry information from one surface it falls upon to another surface it fall upon at a later time.)neufer wrote:A shadow can transmit information and hence canNOT travel faster than c.
(A shadow travels at exactly the speed of light by definition.)
Chris
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