All Questions
Tagged with particle-physics general-relativity
69
questions
-6
votes
0
answers
73
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How can I visualise a sphere with a negative radius? [closed]
I want to visualise the shape of the sphere , will having a negative radius turn the inside of the sphere outside or something other will happen ?
2
votes
0
answers
100
views
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 ...
- 133
0
votes
2
answers
640
views
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 ...
- 4,399
1
vote
0
answers
45
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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.? ...
- 619
0
votes
1
answer
114
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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)
$\nabla_\mu \nabla^\mu \phi=\sum_{a,b} \frac{1}{\sqrt{-g}}\partial_a(\sqrt{-g}g^{ab}\partial_b\phi) =0$
...
- 63
17
votes
6
answers
7k
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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 ...
- 439
0
votes
1
answer
51
views
Equivalent theories of general relativity and graviton spin
Are there equivalent theories of general relativity that assume a graviton has a spin-1?
- 31
2
votes
0
answers
180
views
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 ...
- 21
0
votes
0
answers
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
1
vote
0
answers
57
views
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-...
- 63
1
vote
0
answers
53
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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, ...
- 111
2
votes
0
answers
60
views
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
3
votes
1
answer
198
views
Will the ever accelerating space expansion (like at the level of inflation) eventually break causality?
I have read this question:
requires that "for an action at one point to have an influence at another point, something in the space between the points, such as a field, must mediate the action&...
- 29k
-5
votes
1
answer
103
views
Do objects with different sizes or masses experience time differently when they are moving in a constant velocity in their own reference frame? [duplicate]
My question is actually not about curve spacetime. Just curious if different mass affects how the object experiences time. Hope that someone can give a detailed explanation on this. Thank you!
0
votes
2
answers
117
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Does the mass of a moving object in empty space with a constant velocity change within its own frame of reference from its rest mass?
I believe that a constant velocity moving object in empty space within it own frame of reference retains its rest mass as long as it is moving at constant velocity and an effective mass increase ...
- 4,170