All Questions
Tagged with particle-physics general-relativity
68
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Particles Associated With Gravitational Waves
I've been reading about linearized GR and the study of gravitational waves, and an odd thought popped into my head. According to wave-particle duality (admittedly, usually used in quantum mechanics!), ...
2
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0
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100
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Can squeezed vacuum reduce the mass of a black hole?
Could the negative energy density parts of squeezed light really reduce the mass of a black hole, as stated here (“A pulse of negative energy injected into a charged black hole might momentarily ...
- 135
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2
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645
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Can we regard metric as the Higgs field of gravity?
The longer version of the question is: should we regard special relativity just as a spontaneous symmetry breaking phase of general relativity, driven by the non-zero vacuum expectation value (VEV) of ...
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Does strongly gravitating object travel along geodesic of a background field？ [closed]
That test particles travel along the geodesic is assumed in the context of GR. But does it apply to strongly gravitating object, such as black hole in an expanding universe, binary neutron star, etc.? ...
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How can a grain of sand be "spaghettified" when nearing a black hole?
I have a hard time wrapping my head around this "spaghettification" process that apparently takes places when getting close to a black hole.
Gravity is proportional to the distance of the ...
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5
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1
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Why did Dirac say that atomic time is different from relativistic time, and that gravity is becoming weaker? What is the relation between the two?
In this gem of an interview in 1982 with Friedrich Hund, Dirac says at 09:17 that there is some theoretical basis and observational evidence that atomic time and distances are different from ...
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Energy spectrum in Klein-Gordon equation in general relativity
I know that the Klein-Gordon equation in general relativity takes the form (a massless field)
$\nabla_\mu \nabla^\mu \phi=\sum_{a,b} \frac{1}{\sqrt{-g}}\partial_a(\sqrt{-g}g^{ab}\partial_b\phi) =0$
...
- 16.2k
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Equivalent theories of general relativity and graviton spin
Are there equivalent theories of general relativity that assume a graviton has a spin-1?
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How do I self-study physics at the undergrad level? [closed]
I'm a new physics undergrad worried that I won't be able to learn everything I want at the university I'm going to.
Basically the Institute I'm going to is applied sciences focused, and all electives ...
- 207k
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27
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Does photon energy affect deflection of a beam of light in a gravitational field? [duplicate]
Does photon energy affect deflection of a beam of light in a gravitational field?
According to general theory of relativity angular deflection of a beam of light in a gravitational field is
$$φ = \...
- 101
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Black $p$-brane solution
Im trying to confirm that the metric (11) in the paper below is a solution to Einstein's equations (6). I tried to use the metric and extract $\lambda=(1-(r_+/r)^{D-3})^{1/2-\gamma/2(D-3)}$ and $R=r(1-...
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Is there an upper boundary to magnetism?
This is gonna take some explaining, and full disclosure: I'm still undergrad, so please, forgive my ignorance here. Though please also hear me out: magnetism, like gravity, falls off with distance, ...
- 207k
3
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2
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1k
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Matter and anti-matter collision energy problem
From Beyond Einstein, by Michio Kaku and Jennifer Thompson, Chapter 13, Antimatter :
Dirac, also focused on the fact that Einstein's equation $E=mc^2$ wasn't totally true. (Einstein was aware that ...
CommunityBot
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Evolving energy density of a particle species in cosmology
Suppose you have a momentum distribution of some decoupled $X$ particles in the early universe $f(\mathbf{p})$ that is injected in (well above the electroweak scale so that degrees of freedom for all ...
- 499
11
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What is the difference between a black hole and a point particle?
Theoretically, what is the difference between a black hole and a point particle of certain nonzero mass? Of course, the former exists while it's not clear whether the latter exists or not, but both ...
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