Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Fermion bag solutions to some sign problems in four-fermion field
  theories   Lattice four-fermion models containing $N$ flavors of staggered fermions,
that are invariant under $Z_2$ and U(1) chiral symmetries, are known to suffer
from sign problems when formulated using the auxiliary field approach. Although
these problems have been ignored in previous studies, they can be severe. Here
we show that the sign problems disappear when the models are formulated in the
fermion bag approach, allowing us to solve them rigorously for the first time.

12
The categories of this paper are: nucl-th
17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
2
The categories of this paper are: math
37
The categories of this paper are: supr-con
19
The categories of this paper are: eess
1
The categories of this paper are: cs
23
The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
25
The categories of this paper are: patt-sol
27
The categories of this paper are: comp-gas
5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci