Questions tagged [non-gaussianity]
11 questions
52
votes
7 answers
Are random errors necessarily Gaussian?
I have seen random errors being defined as those which average to 0 as the number of measurements goes to infinity, and that the error is equally likely to be positive or negative. This only requires a symmetric probability distribution about zero.…
Meep
- 4,167
6
votes
0 answers
$f_{NL}$ non-Gaussianity in cosmology
In the context of cosmology, what is meant by "..arbitrary quadratic non-Gaussianity i.e non-Gaussianity that is described to leading order by a 3-point function.."? (.."quadratic non-Gaussianity" sounds like an oxymoron and isn't 3-point function…
Student
- 4,611
5
votes
1 answer
Cosmological fluctuations: what is gaussian?
When we are speaking about gaussianity and non-gaussianity in a cosmological context, what is gaussian or non-gaussian in the CMB?
What would a non gaussian CMB look like compared to a gaussian one?
Is it just the profile of every overdensity…
Vincent
- 1,245
4
votes
1 answer
Entanglement for Gaussian states
Let us consider the product Fock space $\Gamma(\mathbb{C}^m) \otimes \Gamma(\mathbb{C}^n)$ and consider Gaussian states in that space. While reading some literature on Gaussian state entanglement (namely Simon, and Werner and Wolf) , I realised…
RSG
- 1,059
3
votes
1 answer
Normal Distribution vs Poisson Distribution
I am not sure that I understand when to use Normal Distribution and when to use Poisson distribution!
For example, in RF communication the channel noise is mainly modeled as Normal Gaussian distribution, but why? And why not Poisson…
Rudy01
- 161
2
votes
0 answers
How can partial transposition of the Wigner function be achieved in phase space for continuous variables in non-Gaussian states?
The wigner function in phase space is an equivalent description of the quantum-mechanical density matrix $\rho$. The formula for calculating negativity from the density matrix $\rho$ is $\mathscr{N}(\rho )=\frac{
||\rho^{\rm{T}}_A||_1-1}{2}$.
It is…
ffz
- 73
- 5
2
votes
0 answers
Redshift z=40 and gravitational waves
Why z=40 is the critical value of the redshift (more or less) to decide find out primordial gravitational waves around it?
I have read that is related to the following issue: black hole mergers should NOT be detected at certain cosmic age, so…
riemannium
- 6,843
1
vote
0 answers
Can we have a Non-Gaussian Likelihood and which are the conditions or examples?
I am working on Fisher formalism and MCMC method. It seems that Fisher formalisme assumes that posterior is always Gaussian. So if I find with MCMC a gaussian posterior, I validate the results of Fisher computation (by getting a Gaussian…
user87745
1
vote
1 answer
How to quantify elevated tails of a Gaussian like signal?
From some simulations I have obtained as an output a signal which roughly looks like a Gaussian with some elevated tails. Note that the input was a Gaussian.
Now I would like to quantify the deviation from the Gaussian, or, to be more specific, I…
Alf
- 2,039
0
votes
0 answers
Fast way for Phase space eigenvalue calculation beyond the Gaussian states
It is known that Gaussian states admit Gaussian Wigner function in phase space, and calculations of their eigenvalues (i.e., diagonalizing the corresponding destiny matrices in Hilbert space) can be done in the Covariant Matrix (CM) level, providing…
user1475985
- 33
0
votes
1 answer
Do non-Gaussian states always show negativity in phase space?
According to Hudson’s theorem, any pure quantum state with a positive Wigner function is necessarily a Gaussian state. In cases, in which the existing well-known Hudson
theorem immediately tells that the output state, which is non-Gaussian, must…
user0322
- 139