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With respect to the Casimir effect, why can't the wavelengths of the virtual particles between two plates just “pass through” the plates themselves?

I've read over the years that the suppression of many of the possible wavelengths between the two plates in a Casimir experiment is what causes the phenomenon (top comment on this Askscience thread is ...
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2answers
30 views

The source and sink phenomenological description of charge - how realistic is it?

I've heard over and over an electron described as a source of the electric field, but that is a misleading term. Source makes one thing of a tap, with a constant flow of something coming out of it. ...
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1answer
70 views

Two questions about Feynman propagator

Taking for example the meson propagator: $$ \Delta_F (x-y) = \int \frac{d^4k}{(2\pi)^4} \frac{e^{-ik(x-y)}}{k^2 - m^2 + i\epsilon}. $$ It describes a meson that propagate from a point of Minkowski ...
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1answer
38 views

Are there any other pairs similar to virtual and normal photons? [duplicate]

Are there virtual particles for every kind of particle there is?
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1answer
79 views

How is the EM force exchanged over long distances?

The Situation Imagine we place two charged objects a very far distance apart, essentially making them point charges. How does the EM force interact between the two point charges if virtual photons ...
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2answers
38 views

Do anodes emit virtual photons representing their positive electrostatic potential?

I understand the electrons in circuit travel down the path of least resistance, however are electrons attracted by the emission of virtual photons emitted by a source with relatively low electron ...
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2answers
136 views

Are black holes eternal?

The question might sound very easy - Hawking radiation, however I was pondering that as you get closer and closer to a black hole, time dilates exponentially where the surface of the black hole is ...
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4answers
335 views

Do virtual particles actually physically exist?

I have heard virtual particles pop in and out of existence all the time, most notable being the pairs that pop out beside black holes and while one gets pulled away. But wouldn't this actually violate ...
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0answers
36 views

How black hole lose mass? [duplicate]

Even in empty space virtual particles can constantly pop in and out of existence in pairs, when 1 of the pair fall into the black hole while the other escape this is hawking radiation but black hole ...
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0answers
56 views

Why do virtual particles form at black hole horizon? [duplicate]

This question relates to Hawking radiation. I understand about virtual particles - pairs of positive and negative particles that form - but I can't find out why they form at the event horizon and in ...
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1answer
364 views

Is the virtual photon a particle?

I just saw an exam question: Write down the antiparticle for the virtual photon. The answer was "virtual photon". Is the question even a meaningful one? If so please explain why?
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1answer
81 views

What happens to the planck distribution if the temperature is set to zero?

BE Problem I am currently working on modelling the density of states and optical conductivity of graphene utilizing the GW algorithm. In calculating the exchange self energy of the system, the ...
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1answer
147 views

Can photons travel faster than $c$? (Feynman Lectures)

I apologise for the very non-technical nature of this question. I am new to QED and perhaps am interpreting things in the wrong way, but I'll ask anyway, and hopefully someone can provide a ...
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0answers
38 views

Experiment validating existence of virtual particle

I'm curious about virtual particle whether do they really exists, therefore I dug out an experimental theory called lamb shift by measuring the difference between the two energy levels of a hydrogen ...
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1answer
72 views

Virtual particles and the scaling effect on valence quarks

Inside a proton there are 3 valance quarks. In addition, there is constant creation and annihilation of gluon, quarks and anti-quarks. The number of virtual particles we observe depends on how ...
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1answer
100 views

What equation describes virtual photons becoming real photons?

From my understanding, virtual particles are actually "disturbances" between two elementary particle interactions and appear during cross sections of these interactions. What equation(s) describe this ...
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0answers
57 views

Rest masses, binding energy - mechanism for negative mass

Let us have an two objects (in a box) both of mass $m_0$ far from each other. They attract each other and at some moment their distance is close and they have substantial kinetic energy. Something ...
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2answers
211 views

Having Trouble Understanding Feynman Diagrams [closed]

So recently I have became interested in quantum physics. However when I read up on quantum physics Feynman diagrams appear everywhere, and I do not understand them! Here is a Feynman diagram that is ...
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1answer
173 views

Why don't virtual particles violate conservation of mass/energy?

If virtual particles sometimes add more mass/energy to a system then was inputed or comes out in the output, how do they not violate conservation of mass/energy.
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0answers
40 views

How to parametrize off-shellness?

The energy of a massive on-shell particle of mass $m$ and three-momentum $\vec{p}$ satisfies $$E_\vec{p} = \sqrt{\vec{p}^2+m^2}. $$ What would be the analogous expression for an off-shell particle? ...
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1answer
91 views

How can we know that virtual particles exist everywhere in space and not just locally around individual particles our are universe as a whole?

The metaphor of virtual particles that inhabit all of space is used to explain quantum fluctuations. This ceases to be just a metaphor due to the effects of gravity as clumps of any energy (not just ...
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3answers
271 views

Could future experiments on “Gravitational Casimir Effect” confirm the existence of gravitons?

From Casimir effect, we know that when two plates are placed very close to each other in vacuum, they attract each other because the quantum fluctuations that press on the two plates' outer surfaces ...
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0answers
60 views

Physical meaning of the coupling matrix in Fermi golden rule

I am calculating the energy transfer rate using Fermi golden rule where the coupling matrix $M$ is obtained using second order pertubation method. $$ \Gamma_{tran}=\frac{2\pi}{\hslash}|M|^{2}\rho$$ ...
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1answer
84 views

How do photons mediate (or create) a force?

Is there a somewhat intuitive explanation as to why the exchange of a photon between two particles causes a force between those particles? Is there a difference in the way massless and massive ...
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3answers
398 views

Feynman paths of FTL velocity have imaginary momentum?

In this Phys.SE answer it is discussed that Feynman path integrals sums amplitudes for all possible paths, including those that are not time-like. If you take the momentum-space path integrals, I ...
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5answers
4k views

What physical evidence is there that subatomic particles pop in and out of existence?

What physical evidence shows that subatomic particles pop in and out of existence?
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1answer
66 views

Outside of string theory, can exchange particles be understood as being one-dimensional?

I'm pretty new to quantum, without any formal education therein, so forgive my general layman ignorance when I ask how it is that point-like exchange particles can be modeled in Feynman diagrams as ...
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1answer
93 views

What are the virtual particles generated during the Hawking radiation?

What are the virtual particle pairs generated during the Hawking radiation? If a photon is emitted by Hawking radiation, what is its negative energy partner which fell into the black hole? Does it ...
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1answer
69 views

If a particle travelled in a closed timelike curve, would it look like a virtual particle-antiparticle pair?

In Feynman's single-electron hypothesis, he reaches the conclusion that a particle travelling backwards in time will look like its antiparticle. So if we have a particle travelling a closed time-like ...
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0answers
16 views

Does the mediation of electric or magnetic force require distinct electron orbitals?

In the case of ordinary photons of light, matter interacts with light via electrons that orbit the nucleus. If the specific energy of a photon E = hv can be found in the atom as the energy difference ...
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1answer
133 views

Virtual Photon transmission speed of a Static Electric Field?

In the case of a non-accelerating point charge "A" of stable velocity, its static field is treated as though it is instantaneously present at a distance, i.e. a second point charge "B" will react to ...
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2answers
134 views

can we detect the photons in the interaction of two charged bodies?

if the interaction of two charged bodies is through the photon exchange: 1) how much is the energy of these photons and how do we calculate their energies? 2) can these photons be detected by a photon ...
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1answer
146 views

A test for virtual particles by measuring gravity fluctuations possible?

Ok to begin I will begin by talking briefly about my discussions with my Quantum Mechanics (specializes in Particle physics) professor and my Cosmology Professor (who studies particle physics with ...
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1answer
85 views

Which assumption is less plausible, “action at a distance”, or that “virtual particles” can exist for a short time?

It is understood that virtual particle appear in Feynman diagrams as a tool of calculus. And it is understood that they are problematic about their mass, and cannot be detected (is that sure indeed?). ...
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1answer
65 views

External source of virtual particles near a black hole?

I've just read the following quote from the Wikipedia page on Hawking Radiation... In order to preserve total energy, the particle that fell into the black hole must have had a negative energy ...
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2answers
535 views

Are virtual particles limited by the speed of light? [duplicate]

I have recently been reading about Quantum Electrodynamics which I found very interesting, but even more confusing. I understand photons mediate the electromagnetic force and interactions between ...
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2answers
155 views

Moving frames - a blow on “virtual particles”?

There is a polemic about whether virtual particles EXIST, or are only a tool for making our calculi easier. Here is a doubt about their existence, and on the other hand, an argument in support of ...
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2answers
492 views

The virtual particles are only a fictive tool in equations? DO they exist or DON'T? And if they exist, why do we call them VIRTUAL?

There is no "action at a distance" in nature. Attraction of a piece of iron by a magnet, attraction between distant electric charges of opposite sign, have to be mediated by something. The virtual ...
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2answers
264 views

Do virtual photons have a frequency?

Real photons do have frequencies, which is directly related to its energy. So, can virtual photons that take part in EM interactions have frequencies too? When my hand is pressed up against a glass ...
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2answers
174 views

Electromagnetic reaction force?

The classical (retarded) Lienard-Wiechert scalar and vector potentials describe the electromagnetic field due to an arbitrarily moving electric point charge. Thus given the motion of electron $A$ one ...
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1answer
369 views

Energy conservation of Virtual Particles - Quantum Fluctuation?

I (as a middle-school student) was wondering how virtual particles even conserve energy of the entire system? I don't mean just the particle's energy, but conservation with respect to the ...
4
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1answer
245 views

In QED, why is the $e^- + e^+\leftrightarrow\gamma$ process forbidden on-shell?

QED has a vertex that couples a single photon to two fermions. This vertex describes the annihilation of an electron-positron pair into a photon. Why is this process forbidden for all three particles ...
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2answers
408 views

Deriving the Coulomb force equation from the idea of photon exchange?

Since Newton's law of gravitation can be gotten out of Einstein's field equatons as an approximation, I was wondering whether the same applies for the electromagnetic force being the exchange of ...
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2answers
183 views

What happens when Antimatter interacts with a photon?

So... I was just pondering the energy and particles in the universe. It makes sense that matter is attracted to it's self by a gravitational force - it clumps and forms some kind of gravity ...
1
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1answer
62 views

how is an electron able to emit and absorb the same (virtual) photon?

When calculating the lowest order self energy corrections for an electron for example, feynman diagrams involving the emission and re-absorption of a (virtual) photon need to be considered, (as here ...
1
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0answers
44 views

Hawking Radiation: Couldn't virtual particles make black holes more massive? [duplicate]

From what I understand about Hawking radiation, a virtual particle comes into existence very near the event horizon of a black hole. This causes one part of the particle to fall into the black hole, ...
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4answers
201 views

Virtual particles/quantum tunneling - conservation of energy?

I'm confused as to how the above phenomena can take place since arent they breaking the law of conservation of energy (even, if temporarily)?
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2answers
215 views

Hawking Radiation and virtual particles

Why is energy/ mass taken away from a black hole? Doesn't the energy coming from the virtual particle come from the vacuum energy? ...if this is so, why does the black hole have to pay the energy ...
3
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2answers
106 views

Is it possible to create matter from space?

Like could maybe fluctuate the space some how and make the virtual paricles turn into normal matter
3
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3answers
178 views

How does a photon “know” that it's left one charge and that it's going to another one?

How does it know the same charge it left will be the same charge it will return to? My understanding is photons are neutral and have no charge. i.e. Like charges repel, unlike attract. All charged ...