Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Finite-size effects in Luther-Emery phases of Holstein and Hubbard
  models   The one-dimensional Holstein model and its generalizations have been studied
extensively to understand the effects of electron-phonon interaction. The
half-filled case is of particular interest, as it describes a transition from a
metallic phase with a spin gap due to attractive backscattering to a Peierls
insulator with charge-density-wave (CDW) order. Our quantum Monte Carlo results
support the existence of a metallic phase with dominant power-law charge
correlations, as described by the Luther-Emery fixed point. We demonstrate that
for Holstein and also for purely fermionic models the spin gap significantly
complicates finite-size numerical studies, and explains inconsistent previous
results for Luttinger parameters and phase boundaries. On the other hand, no
such complications arise in spinless models. The correct low-energy theory of
the spinful Holstein model is argued to be that of singlet bipolarons with a
repulsive, mutual interaction. This picture naturally explains the existence of
a metallic phase, but also implies that gapless Luttinger liquid theory is not
applicable.

19
The categories of this paper are: eess
17
The categories of this paper are: q-fin
36
The categories of this paper are: cmp-lg
12
The categories of this paper are: nucl-th
37
The categories of this paper are: supr-con
0
The categories of this paper are: hep-ph
26
The categories of this paper are: bayes-an
30
The categories of this paper are: q-alg
27
The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph
35
The categories of this paper are: mtrl-th
3
The categories of this paper are: physics
21
The categories of this paper are: adap-org
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
14
The categories of this paper are: math-ph