All Questions
7
questions
0
votes
2
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Are there introductory reviews of trans-Planckian physics and inflation? Looking for something similar to Daniel Baumann's cosmology notes
Are there introductory reviews of trans-Planckian physics and inflation? Looking for something similar to Daniel Baumann's cosmology notes - things are explained assuming minimal background.
32
votes
4
answers
13k
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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, ...
- 95.6k
2
votes
0
answers
95
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How does the direction of time work with timeless wave functions?
In thermodynamical theory, if we have a set of states for example:
A) gas all in top left corner of box.
B) gas spread out near the left.
C) gas spread out to fill entire box.
We can give the ...
user84158
1
vote
1
answer
337
views
Does quantum field theory need time?
I've been reading about quantum cosmology and how it doesn't have a universal time variable so-to-speak. Instead it uses certain fields as clocks with which to compare other fields.
Now, it got me ...
user84158
4
votes
2
answers
510
views
What is the interpretation of a wave function of the Universe in Hawking's no boundary proposal?
In the path integral formalism we have an in state $\Psi_{in}[\phi]$ and and out state and we find the amplitude for going from one to the other:
$$\Delta[\Psi_{in},\Psi_{out}] = \int \Psi_{in}[\phi]...
user84158
9
votes
1
answer
2k
views
Dirac Equation in General Relativity
Dirac equation for the massless fermions in curved spase time is $γ^ae^μ_aD_μΨ=0$, where $e^μ_a$ are the tetrads. I have to show that Dirac spinors obey the following equation:
$$(−D_μD^μ+\frac{1}{4}R)...
- 353
8
votes
3
answers
1k
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Physical origin of the inflaton field?
I have two particular questions regarding the inflationary scenario. They are:
What is the physical origin of the inflaton field?
Why has the potential of the inflation field its particular form?
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