All Questions
61
questions
-2
votes
2
answers
115
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What is the current most widely-accepted explanation of gravity? [closed]
What do physicists typically say gives gravity the ability to act on a pair of objects?
I am not asking for a description of gravity as a scalar field, but rather what the current accepted theory is ...
1
vote
0
answers
64
views
Reparameterization invariance in gravity
It's often said that gravity/general relativity has 'reparameterization invariance.' In particular, this comes up when people talk about the duality between the Sachdev-Ye-Kitaev (SYK) model and ...
- 2,504
-1
votes
1
answer
230
views
White Holes Evidences
It is well known that in the canonical quantization program for quantum gravity, like LQG/Wheeler-De Witt/Polymer QM,
almost every prescription when applied to cosmology/gravitational collapse leads ...
- 1,611
0
votes
0
answers
75
views
Why is gravity not quantum? [duplicate]
My main question is about brief information about gravity. For example, why is gravity not quantum?
What is the main problem with gravity? Why is gravity the weakest force?
Of course, from the ...
- 65
2
votes
1
answer
596
views
Lagrangian of a graviton
Recently in an interview for a phd program I was asked how would you write the lagrangian of a graviton. I answered that since graviton is a massless particle it's lagrangian should be similar to the ...
user321957
3
votes
3
answers
357
views
How does string theory relate superposition and general relativity?
So I know that in general relativity, superposition cannot be true. However, since string theory supposedly connects quantum mechanics and gravity, how does it relate superposition and gravity?
- 625
0
votes
1
answer
161
views
How is gravitational time dilation different from the time dilation from Special Reativity? [duplicate]
In Special Relativity, acceleration i.e. a changing velocity 4-vector results in time dilation, that is asymmetric aging of observers.
In General Relativity, the 4-vector does not change along a ...
- 519
0
votes
1
answer
152
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Replacing $U(1)$ covariant derivative with $GL(4,\mathbb{R})$ covariant derivative... does it give quantum gravity?
I realize that many questions about deriving quantum gravity have been asked multiple times before on this forum, but it hasn't been asked exactly like I am doing here. I would like to know what ...
- 1,548
3
votes
2
answers
247
views
Quantum gravity in an accelerated frame of reference
It is said that we can't study quantum gravity because gravity is a weak force. But gravity and acceleration are the same. Why can't we study quantum gravity in a strongly accelerated frame of ...
- 31
15
votes
8
answers
2k
views
What is the true nature of gravity? [closed]
In 17th century, Sir Isaac Newton gave us the universal law of gravitation which stated that gravity is an inverse square force. In 1915, Albert Einstein recognised gravity as a curvature of space-...
- 255
1
vote
1
answer
53
views
Differences between observations of light versus gravity for a satellite traveling by the sun
A satellite travels in a geodesic by the sun with sufficient velocity to escape the sun's orbit. The distance of closest approach is 100 light seconds when the satellite's velocity is perpendicular ...
- 143
9
votes
4
answers
1k
views
Gravitons and general relativity
First I want to say that I am a layperson, so I want intuitive answers.
So all the 3 fundamental forces in nature has a carrier particle except gravity. So we have hypothesized the existence of ...
- 737
1
vote
1
answer
97
views
How can gravity be describe as a carried on gravitons if light is affected by gravity but no effect on gravity? [duplicate]
if photons are emitting graviton while it going near to mass then this graviton should effect the mass the much as the graviton that object with mass emit, and we know light have no mass so it not ...
- 149
1
vote
0
answers
47
views
Why cannot we add gravity in quantum mechanics without additional dimensions as done in bosonic or superstring theory? [duplicate]
Is it because Einstein described gravity not as a force but as a curvature of spacetime? Physicists usually say that it is hard to combine quantum mechanics with gravity. But I had doubt, is it ...
- 41
2
votes
1
answer
190
views
GR vs QM: if gravity is a force then what is space-time?
As described by the GR theory, gravity is the curvature of space-time.
On the other hand in quantum mechanics gravity tends to be described as a force, related to it's hypothetical particle called ...
