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6
votes
2answers
173 views

Do gravitational waves cause time dilatation?

The effect of gravitational waves in transverse traceless gauge on matter is represented by the expansion and contraction of a ring of test particles in the direction of polarization of the wave. ...
7
votes
1answer
101 views

In the B mode power spectrum, what is the relationship between the multipole number and the wavelength of the seed gravitational waves?

One of the key datasets of the recent BICEP2 results is the B mode power spectrum shown below. The existence of these B modes implies the existence of gravitational waves prior to inflation. My ...
3
votes
1answer
468 views

warp drive with gravitational waves in the nonlinear regime

gravitational waves are strictly transversal (in the linear regime at least), also their amplitudes are tiny even for cosmic scale events like supernovas or binary black holes (at least far away, ...
1
vote
1answer
66 views

The gravity waves from the big bang? How can we know?

The latest news says that scientists detected gravitational waves from the Big Bang. My question is how do they know the waves originated in the big bang verses any number of supernovae and or ...
-1
votes
1answer
96 views

How to detect gravitational waves?

Gravitational waves just have a little interaction with other particles. How can we detect such little influence on mass?
4
votes
0answers
148 views

Would warp bubbles emit gravitational Cerenkov radiation in general relativity?

Inspired by the gravtiomagnetic analogy, I would expect that just as a charged tachyon would emit normal (electromagetic) Cerenkov radiation, any mass-carrying warp drive would emit gravitational ...
3
votes
0answers
53 views

What are the current experimental restrictions of the possible speeds of gravitation?

Somewhere I read that the Hulse-taylor binary pulsar can not differentiate between competing theories assuming different speeds of gravity. Is it mathematically true in general, that the orbital decay ...
2
votes
0answers
114 views

What does BICEP2's results tell us about gravitation waves and quantum gravity?

The BICEP2 results, unless I am mistaken, are a measurement of CMB polarization, i.e. photon polarization. That is, taken at face value they say nothing about gravity directly. Now, we can start to ...
2
votes
0answers
87 views

Gravitational waves as information carriers

Is it possible to utilize gravitational waves as a delivery system for information between two observers straddling the event horizon of a black hole? And why ?
1
vote
0answers
45 views

Riemann curvature tensor in first order perturbation theory as a Lie derivative of Riemann curvature tensor in zero order

I am having a difficulty solving my homework so I was hoping I could get some help, so here it is. It is about gravitational waves and first order gravitational perturbation theory, I have to prove ...
1
vote
0answers
62 views

Thermal gravitational radiation and its detection

To my poor knowledge on the topic, the gravitational waves that are most likely to be detected by LIGO or other experiments do not have thermal spectrum. But I'm not certain. I know that Hawking's ...
0
votes
0answers
36 views

What are the implications of the possibility that the BICEP2 results are caused by a self ordering scalar field transition?

I've found this interesting paper that mentions another possible way to interpret the recent BICEP2 results, and that hadn't been ruled out yet 1. As interesting as the possibility that the BICEP2 ...
0
votes
0answers
47 views

One more time about the connection of Weyl tensor and gravitational waves

There is differential identity with Weyl tensor and energy-momentum tensor: $$ D^{\lambda}C_{\lambda \alpha \sigma \beta} = 4 \pi G \left(D_{\sigma}T_{\alpha \beta} - D_{\beta}T_{\alpha \sigma} + ...
0
votes
0answers
74 views

Counterpart of the Klein Gordon Equation on the “Coordinate Shell”

The relation $$\psi=Ce^{i/\hbar(Et-\mathbf{p}\cdot\mathbf{x})}\tag{1}$$ satisfies the Klein Gordon equation on the mass shell, i.e. for $E^2=p^2+m^2$. Now let's think in the reverse direction. ...
0
votes
0answers
48 views

Emitting gravitational radiation

Is the following true: Two massive bodies with variable distance between them do not emit GR in any direction Two bodies that revolve around common center will not emit in the plane of their orbits ...
0
votes
0answers
73 views

Does quantum field theory accept gravitational wave?

Does quantum field theory accept gravitational wave? As quantum field theory is flat spacetime theory, I wonder whether gravitational wave would be true. Does contemporary string theory variants ...