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3answers
391 views

Understanding forces in QFT [closed]

I recently came to know that any type of force is exerted by a particle on another with the help of gauge bosons/virtual particles which are in reality a mathematical aide and do not have actual ...
2
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1answer
216 views

Virtual particles and S-matrix

One of methods of introducing of virtual particles is using perturbation theory. We say that scattering matrice amplitude $M_{in \to out}$ contains of $\delta(P_{out} - P_{in})$, which realizes ...
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8answers
5k views

Can the magnetic lines of force of two or more magnets intersect each other?

Basic property of magnetic lines of force is that, they can never intersect each other. Among the two points given below, which one is correct? Magnetic lines of force of same magnet can't intersect ...
1
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3answers
117 views

Can the vacuum be filled with virtual micro-black holes?

Since the vacuum is thought to be virtual particles, is it possible that there might be virtual micro-black holes with virtual horizons and virtual hawking radiation which form and evaporate at a rate ...
4
votes
2answers
591 views

Some questions about virtual particles

When reading about quantum mechanics, I've stumbled upon a description of the force between two electrons as a result of virtual particles being "exchanged" by the two electrons. So far I've ...
7
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4answers
886 views

Hawking Radiation - Why it causes black holes to die? [duplicate]

If a particle is being expelled from the Black Hole and an antiparticle is being driven into it, shouldn't the opposite occur as well and in the same frequencies? I mean Black holes should emit ...
1
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0answers
78 views

How often can virtual particle/antiparticle pairs form real particles in a space expanding sufficiently fast to do this?

And if the rate of expansion of the universe becomes sufficient for virtual particles to be ripped apart into real particles, what effect would the mass of these particles have on the rate of ...
3
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0answers
105 views

At what expansion rate (H) would virtual particles be ripped apart into real particles, and what might be the density (temperature) of such an event?

Is it even possible for a virtual particle-antiparticle pair to be torn apart by cosmological expansion? Virtual particle-antiparticle pairs are ripped apart near black hole event horizons, creating ...
-1
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1answer
95 views

Virtual Particles and Quantum Brownian Motion

Does the frequency of virtual particles (creation/annihilation) match with nucleus random paths - known as Quantum Brownian Motion?
2
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2answers
847 views

Are there any other mechanisms that can make virtual particles 'real' other than Hawking Radiation and Universe Births?

As I understand it, if virtual particles do not recombine within the plank time they become 'real'. This is proposed to happen in Hawking Radiation, where one virtual particle crosses the black ...
7
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2answers
1k views

Virtual photons, what makes them virtual?

The wikipedia page "Force Carrier" says: The electromagnetic force can be described by the exchange of virtual photons. The virtual photon thing baffles me a little. I get that virtual particles ...
1
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1answer
338 views

Conservation of Energy and Quantum Fluctuations

Regarding conservation of mass-energy Wikipedia says: "this is an exact law, or more precisely, has never been shown to be violated." However, regarding quantum fluctuations, Wikipedia says here: ...
4
votes
2answers
151 views

Will the increasing rate of expansion of the universe eventually result in Hawking Radiation suddenly occurring everywhere?

The universe is expanding at an ever increasing rate. Virtual particles are being created and then destroyed everywhere at every moment. As space expands even faster, will a time come when these ...
3
votes
1answer
255 views

Quantum field theory quote

I have read this in scientific American: According to quantum field theory, all particles spend a little time as combinations of all other particles" Is this right? How long? And how can they be a ...
3
votes
2answers
781 views

Photon as the carrier of the electromagnetic force

My physics background goes as "far" as reading popsci books on QM, Particle Physics, and Cosmology so pardon my ignorance in the below questions. I've read that the photon is the particle (quanta in ...
11
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1answer
467 views

How is it possible the speed of light is not constant?

I was reading this article recently, which summarizes a couple of new studies into the speed of light. In one paper, Marcel Urban from the University of Paris-Sud, located in Orsay, France and his ...
6
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1answer
261 views

Quantum Electrodynamics

I was wondering if anyone could give a simple explanation of how light interacts with matter. From what I have read in QED, electrons will repel each other because of their ability to emit and ...
0
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2answers
254 views

Why does Quantum Electrodynamics Allow a Photon to Exist Temporarily as a Positron and an Electron?

In this question... Why does a photon colliding with an atomic nucleus cause pair production? ...I asked why a photon colliding with a atomic nucleus can become an electron and a positron. The ...
2
votes
1answer
96 views

Time taken for gravity of a distant object to interact with a newly created particle? [duplicate]

Possible Duplicate: The speed of gravity Does gravity travel at the speed of light? Imagine there is a large mass $m_1$ (e.g. a star) 1 light-year away from us. It is stable, stationary ...
1
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2answers
1k views

Is all matter made of virtual particles?

This article in New Scientist says that all matter is actually virtual particles popping in and out of existence and nothing more. is this correct?
5
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2answers
10k views

What exists in the Space between atoms

Apologies to all if this has been asked before, I searched but was unable to find one similar. This is a question that has been bugging me for a while that i haven't really been able to find a ...
1
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1answer
1k views

Is it possible that the Big Bang was caused by virtual particle creation?

As far as I understand, it is understood that throughout the universe there exists, what is known as, a quantum field from which, due to its fluctuations, temporary (pairs of) virtual particles ...
1
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1answer
298 views

Speed of light and virtual particles

After becoming extremely bored while studying for an Afrikaans exam, I started thinking about virtual particles. So, can light (photons) interact with virtual particles (even though they only exist ...
7
votes
3answers
693 views

What makes a Feynman diagram real or virtual?

Simple question: as the title says, what makes a real Feynman diagram real, and what makes a virtual diagram virtual? Or in other words, how do I tell whether any given diagram is real or virtual? ...
2
votes
0answers
160 views

photon and Z boson interference?

I'm not certain that this question will make sense, but here goes... In most monte carlo generators, when Z events are produced, there is a lower mass cutoff on the Z pole. I've been told that this ...
7
votes
3answers
730 views

What really goes on in a vacuum?

I've been told that a vacuum isn't actually empty space, rather that it consists of antiparticle pairs spontaneously materialising then quickly annihilating, which leads me to a few questions. ...
6
votes
2answers
945 views

How do we distinguish between virtual particle exchange and particle decay?

The difference between virtual particles and unstable particles is discussed at length in this question (namely, virtual particles correspond to internal lines in Feynman diagrams and are not ...
3
votes
1answer
202 views

Virtual particles in semiclassical Quantum mechanics

(I'm just wondering if some of the concepts in QFT can be exported back to QM, especially the concept of virtual particle) So I've just read Arnold Neumaier's description about virtual particle in ...
5
votes
1answer
653 views

The nature of time, according to quantum field theory

I will try my best to ask the question that best fits something I have been pondering on for a few days. Are virtual particles really constantly popping in and out of existence? Or are they ...
2
votes
2answers
325 views

Does path integral and loop integral in a Feynman diagram violate special relativity?

Consider a correlation function between two points $A(x_1,t_1)$ and $B(x_2,t_2)$, we need to integrate over paths which could be infinite long. But the time length $(t_1-t_2)$ is finite, so if $A$ ...
3
votes
3answers
994 views

what causes virtual particle pair production to not occur in the space occupied by matter?

Are virtual particles only popping in and out of existence where the local energy density is below a certain point? What I wonder is, does any kind of matter prevent the pairs from appearing? Is ...
24
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4answers
5k views

Are W & Z bosons virtual or not?

W and Z bosons are observed/discovered. But as force carrying bosons they should be virtual particles, unobservable? And also they require to have mass, but if they are virtual they may be off-shell, ...