All Questions
Tagged with cosmologyquantum-field-theory
165 questions
0votes
0answers
53views
Dark matter freeze-out in the Early Universe
Let us consider an Early Universe scenario in which I have dark matter particles (DM) $\chi_1$ and $\chi_2$, with a small mass splliting $\delta \ (m_2 = m_1 + \delta, \quad \delta \ll m_1, m_2)$, ...
- 81
2votes
0answers
33views
Massive "Photon" on de Sitter (Inflation) Reference
I am trying to find a reference for massive $U(1)$ or "massive photon" during inflation (or de Sitter space) that derives or at least shows the mode functions for massive photon (with the ...
2votes
0answers
34views
$n$-point spin-1 vertex in de Sitter?
To setup the motivation for this question, consider the following $n$-point interaction vertex that we will take to be in de Sitter space so that we can make predictions during inflation, where we are ...
- 1,073
0votes
0answers
81views
Inflationary power spectrum
I'm writing work devoted to the study of the inflationary model in modified gravity theory. So I need derive power spectrum - $\Delta^2_{\mathcal{R}}$, $\Delta^2_h$. But in a lot of book an auxiliary ...
0votes
0answers
22views
Is there a model for the synthesis of light-sector heavy hadron formation during a first order phase transition?
I've recently been reading some research on theories of dark matter. So, I read about Fermi-balls (https://arxiv.org/abs/2008.04430), or non-topological solitons bound inside their own domain walls. ...
1vote
0answers
39views
Spin-$s$ Effective Field Theory of Inflation Equations of Motion
Suppose in $D = d+1$ dimensional spacetime, that I have the following action for integer spin particles with spin-$s$ given by the following action (note: primes denote conformal derivatives i.e. $\...
- 1,073
1vote
1answer
66views
Are theories related by field redefinitions unitarily equivalent after quantization? [closed]
So on the classical level two theories is of course equivalent after field redefinitions. I wonder if such equivalence persists after quantization. In cosmology, it is a common practice to do some ...
- 401
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40views
Solving second-order differential equation for inflationary fields in the late-time limit
I need your help guys. I have been reading this paper by Weinberg hep-th/0506236, and I am stuck in figuring out how he wrote the solution of some differential equations for various inflationary ...
1vote
0answers
60views
Gauge field correlation function in de Sitter space
Back in the 1970s Bunch and Davies derived a two-point correlation function for heavy scalar fields in de Sitter space. They used the method of point-splitting renormalization. I have been searching ...
0votes
1answer
93views
Cosmological constant from the view of renormalization
A quick question: Is the appearance of the cosmological constant the puzzling part, or the smallness of it compared to other typical scales (Higgs VEV for example). Because given (semi-classical) ...
0votes
0answers
34views
2-Dimensional Cosmology and Power Spectrum
First, full disclosure, I am not even sure yet if this question makes sense, but I tried to derive some stuff, and would love some feedback. First, recall that in $d=4$, we can write the de Sitter ...
- 1,073
0votes
0answers
155views
Singularity structure being valid for all QFTs?
I'm trying to understand this paper in which the authors try to build a wavefunction for the universe without assuming locality and unitarity, so they would be rather emergent from geometrical ...
- 3,018
1vote
0answers
70views
Equation of motion for a Proca field in Robertson Walker metric
this is my very first question, I hope to do everything in a proper way. The problem I have is about a vector field in a flat-Robertson metric: \begin{equation} d s^2=d t^2-a^2(t)d\vec{x}^2,\quad \...
2votes
1answer
80views
Why is it necessary the inflaton field?
The Friedmann equations read $(+---)$: $$\frac{\dot{a}^2+kc^2}{a^2} = \frac{8\pi G\rho + \Lambda c^2}{3}$$ $$3\frac{\ddot{a}}{a} = \Lambda c^2 - 4\pi G \left(\rho + \frac{3p}{c^2}\right)$$ $$\dot{\rho}...
- 751
4votes
1answer
130views
Can there be a progressive and slow vacuum transition event instead of a sudden one?
I have a question on transition events between vacua, and what do our models predict that would happen: Could there be a transition between vacua without involving a sudden event like a bubble ...
- 3,018
