Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The von Neumann entropy for the Pearson correlation matrix: A test of
  the entropic brain hypothesis   We address the general problem of how to estimate an entropy given a Pearson
correlation matrix. Most methods currently in use inject a degree of
arbitrariness due to the thresholding of correlations. Here we propose an
entirely objective method of entropy estimation that requires no thresholding.
Let $\boldsymbol{R}$ be an $N\times N$ Pearson correlation matrix. We define
the matrix $\boldsymbol{\rho} = \boldsymbol{R}/N$ and prove that
$\boldsymbol{\rho}$ satisfies all the properties required of the density
operator. Hence, the von Neumann entropy
$S=-\operatorname{tr}\,(\boldsymbol{\rho} \log \boldsymbol{\rho})$ can be
directly calculated from the Pearson correlation matrix. To demonstrate the
generality and power of the method, we estimate the entropy of functional
correlations of the human brain. We find that the entropy increases for altered
brain states under serotonergic agonist action, as predicted by the entropic
brain hypothesis.

26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
18
The categories of this paper are: econ
5
The categories of this paper are: gr-qc
12
The categories of this paper are: nucl-th
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
11
The categories of this paper are: hep-lat