All Questions
Tagged with quantum-field-theory general-relativity
65
questions
35
votes
2
answers
10k
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Energy-Momentum Tensor in QFT vs. GR
What is the correspondence between the conserved canonical energy-momentum tensor, which is $$ T^{\mu\nu}_{can} := \sum_{i=1}^N\frac{\delta\mathcal{L}_{Matter}}{\delta(\partial_\mu f_i)}\partial^\nu ...
- 2,024
28
votes
3
answers
4k
views
No hair theorem for black holes and the baryon number
The no hair theorem says that a black hole can be characterized by a small number of parameters that are visible from distance - mass, angular momentum and electric charge.
For me it is puzzling why ...
- 6,480
16
votes
8
answers
42k
views
Is gravity just electromagnetic attraction?
Recently, I was pondering over the thought that is most of the elementary particles have intrinsic magnetism, then can gravity be just a weaker form of electromagnetic attraction? But decided the ...
- 1,804
28
votes
2
answers
7k
views
Suggested reading for quantum field theory in curved spacetime
I want to learn some QFT in curved spacetime. What papers/books/reviews can you suggest to learn this area? Are there any good books or other reference material which can help in learning about QFT ...
32
votes
4
answers
13k
views
Why is quantum gravity non-renormalizable?
The book The Ideas Of Particle Physics contains a brief treatment of quantum gravity, in which the claim is asserted that if one attempts to construct a model of gravity along the same lines as QED, ...
- 95.5k
29
votes
4
answers
11k
views
Why you need a graviton when you have the Higgs boson?
Since I studied General Relativity I had this question running on my mind. As I see it (just taking lectures of Quantum Field Theory right now)
"Why you need a gauge boson for gravity when the ...
- 712
13
votes
1
answer
1k
views
What's the key point to argue that pure gravity can't be renormalizable from two-loop?
Gravity is not power-counting renormalizable in dimensions greater than two. It is known by Gerard 't Hooft, M.J.G. Veltman
that pure gravity in four-dimensions is finite to the first loop order ...
- 2,147
11
votes
3
answers
3k
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Why is there a “problem of time” in Quantum Gravity?
It’s often said that the problem of time exists because time is treated as absolute in quantum mechanics but not so in General Relativity, see e.g. A list of inconveniences between quantum mechanics ...
- 2,123
5
votes
1
answer
878
views
Quantization surface in QFT
What does the Quantization Surface mean here?
Reference: H. Latal W. Schweiger (Eds.) - Methods of Quantization
- 3,023
10
votes
4
answers
2k
views
Why gauge theories have such a success?
[This question was inspired by a identical question asked on a other forum]
Note that we may morally include general relativity in the gauge theories.
We may have several (some are deliberately ...
- 17.7k
17
votes
3
answers
4k
views
Advantages of using different metric signatures in relativity and QFT
I am studying General Relativity and some basic QFTs. It bothers me a lot that different books use different metric signatures, i.e. $(-+++)$ and $(+---).$ Can anyone tell me the advantages of using ...
- 171
8
votes
1
answer
2k
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Modern treatment of effective QFT in curved spacetime
Is Ch. 6 of Birrell & Davies book on QFT in curved space and in particular the 1-loop effective action that they derive up-to-date with the current state of the art in (effective) quantum gravity? ...
4
votes
3
answers
2k
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Is space-time a special form of energy?
I know space-time can be influenced by matter and energy, so it must be somehow mingled in with the mix of it all, but does space-time have a fundamental particle? Can we make a little bit of space-...
- 91
25
votes
5
answers
2k
views
Dependence of spin on classical vs non-classical physics?
Textbook derivations often state that spin can be derived by adding relativity to quantum mechanics. The general argument comes in several steps :
Schrödinger first tried to describe quantum ...
- 819
21
votes
3
answers
4k
views
Is the universe non-linear?
First of all, I've read this other question Is the universe linear? If so, why? and I'm aiming at a different kind of answer.
Theories like General Relativity or QFT, which are believed to be quite ...
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