Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Gross-Neveu model on a sphere with a magnetic monopole   We study, for the first time, the phase structure of the Gross--Neveu model
with a combination of a (constant) gravitational and a magnetic field. This has
been made possible by our finding of an exact solution to the problem, namely
the effective potential for the composite fermions. Then, from the
corresponding implicit equation the phase diagram for the dynamical fermion
mass is calculated numerically for some values of the magnetic field. %(what
can be done with arbitrary precision). For a small magnetic field the phase
diagram hints to the possibility of a second order phase transition at some
critical curvature. With growing magnetic field only the phase with broken
chiral symmetry survives, because the magnetic field prevents the decay of the
chiral condensate. This result is bound to have important consequences in early
universe cosmology.

2
The categories of this paper are: math
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org
35
The categories of this paper are: mtrl-th
0
The categories of this paper are: hep-ph
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
22
The categories of this paper are: chao-dyn
4
The categories of this paper are: cond-mat
34
The categories of this paper are: chem-ph
3
The categories of this paper are: physics
6
The categories of this paper are: astro-ph
25
The categories of this paper are: patt-sol