Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the sign problem in dense QCD   We investigate the Euclidean path integral formulation of QCD at finite
baryon density and temperature. We show that the partition function Z can be
written as a difference between two sums Z+ and Z-, each of which defines a
partition function with positive weights. We call the sign problem severe if
the ratio Z-/Z+ is nonzero in the infinite volume limit. This occurs only if,
and generically always if, the associated free energy densities F+ and F- are
equal in this limit. We present strong evidence here that the sign problem is
severe at almost all points in the phase diagram, with the exception of special
cases like exactly zero chemical potential (ordinary QCD), which requires a
particular order of limits. Part of our reasoning is based on the analyticity
of free energy densities within their open phase regions. Finally, we describe
a Monte Carlo technique to simulate finite-density QCD in regions where Z-/Z+
is small.

30
The categories of this paper are: q-alg
34
The categories of this paper are: chem-ph
24
The categories of this paper are: dg-ga
6
The categories of this paper are: astro-ph
33
The categories of this paper are: plasm-ph
16
The categories of this paper are: stat
12
The categories of this paper are: nucl-th
9
The categories of this paper are: nlin
29
The categories of this paper are: funct-an
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess
35
The categories of this paper are: mtrl-th
13
The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg