All Questions
Tagged with cosmology quantum-mechanics
40
questions with no upvoted or accepted answers
7
votes
0
answers
116
views
How many apparent horizons could the universe have?
I was reading a paper written by Nobel laureate George Smoot, Go with the Flow, Average Holographic Universe, which assumes the holographic principle as true and conjectures that our universe would be ...
- 2,462
5
votes
0
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82
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Bargmann–Wigner equations in NP formalism
Bargmann-Wigner equations describe free particles of arbitrary spin $j$, namely
$$(-\gamma^{\mu}\partial_{\mu}+m)_{\alpha_r \alpha_{r’}}\Psi_{\alpha_1,..,\alpha_{r’},...,\alpha_{2j}}=0$$
where we have ...
- 341
4
votes
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answers
109
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What is the best way to describe a classical field in quantum field theory (coherent state)?
In quantum field theory, we have the following expansion on a scalar field (I follow the convention of Schwarz's book)
$$\phi(\vec{x},t)=\int d^3 p \frac{a_p exp(-ip_\mu x^\mu)+a_p^{\dagger}exp(ip_\mu ...
- 442
3
votes
1
answer
132
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Cosmological perturbations and energy in an expanding universe?
I was reading an interesting book from cosmomogist Viatcheslav Mukhanov Physical Foundations of Cosmology and I had a specific question about it:
It is usually said that energy conservation is ...
- 2,462
3
votes
0
answers
84
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How to understand the Wheeler-de Witt equation correctly?
I am a student and for me it is still quite difficult to understand the Wheeler-de Witt equation for the wave function of the Universe. This is a kind of analogue of the Schrödinger equation, which ...
- 956
3
votes
0
answers
47
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Entanglement and cosmological eras
I'm checking this paper: https://arxiv.org/abs/1405.7834
In the context of quantum cosmology, they assume that the universe evolves in an entangled state between the two epochs considered, i.e.$$\...
2
votes
0
answers
112
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Toy example of superdeterminism using Rule 30
From what I understand of Bell's Theorem, it requires giving up local realism or embracing superdeterminism. I still haven't been able to understand why superdeterminism gets such a bad rap, so I've ...
- 204
2
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35
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Does the history of the universe change when the initial conditions change in superdeterministic theories?
In quantum mechanics, superdeterminism is a loophole in Bell's theorem, that allows one to evade it by postulating that all systems being measured are causally correlated with the choices of which ...
- 956
2
votes
0
answers
72
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Would the nightsky be bright (filled with starlight) without accelerating space expansion?
As I currently understand, if a photon was emitted from a far away point in the Universe, beyond the event/particle horizon, so that the space inbetween the emitter and us is expanding faster then ...
- 29k
2
votes
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answers
76
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What caused the first measurement to the universe?
I've been bumbling with a question recently. People postulate that with the give model of big ban, particles forms and breaks and eventually became what we saw as of today.
However, if we put ...
- 3,256
2
votes
0
answers
662
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Is Gerard 't Hooft's Cellular Automaton Interpretation of Quantum Mechanics background independent?
In Gerard 't Hooft in his Cellular Automata Interpretation of Quantum Mechanics
(https://www.researchgate.net/publication/...
user234845
2
votes
0
answers
98
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What's the difference, if any, between Soft Hair & Quantum Hair
In the early 90s, John Preskill, Sidney Coleman, Frank Wilzcek and Lawrence Krauss presented a series of papers [1][2][3] on Quantum Hair on Black Holes due to Cosmic strings in a number of ways ...
- 425
2
votes
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answers
61
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Would Bekenstein bound disappear in some holographic models?
In Holographic principle models there's a limit to the information that the system can store known as the "Bekenstein bound".
In physics, the Bekenstein bound is an upper limit on the entropy S, or ...
user225063
2
votes
0
answers
308
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Computations for Quantum Vacuum Fluctuations
For quite some time the notion of quantum vacuum fluctuations is bothering me.
What exactly is the theoretical origin of this notion? This notion has become quite common in physics and is used to ...
- 10.1k
2
votes
0
answers
136
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Topological Solitons and the Higgs Condensate entanglement
While focusing on resolutions to the Firewall controversy, and the possible implications of the Higgs field as it relates to the issue, the possibility of using EPR correlations in the Higgs ...
- 4,892