Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Steady-state phase diagram of quantum gases in a lattice coupled to a
  membrane   In a recent experiment [Vochezer {\it et al.,} Phys. Rev. Lett. \textbf{120},
073602 (2018)], a novel kind of hybrid atom-opto-mechanical system has been
realized by coupling atoms in a lattice to a membrane. While such system
promises a viable contender in the competitive field of simulating
non-equilibrium many-body physics, its complete steady-state phase diagram is
still lacking. Here we study the phase diagram of this hybrid system based on
an atomic Bose-Hubbard model coupled to a quantum harmonic oscillator. We take
both the expectation value of the bosonic operator and the mechanical motion of
the membrane as order parameters, and thereby identify four different quantum
phases. Importantly, we find the atomic gas in the steady state of such
non-equilibrium setting undergoes a superfluid-Mott-insulator transition when
the atom-membrane coupling is tuned to increase. Such steady-state phase
transition can be seen as the non-equilibrium counterpart of the conventional
superfluid-Mott-insulator transition in the ground state of Bose-Hubbard model.
Further, no matter which phase the quantum gas is in, the mechanic motion of
the membrane exhibits a transition from an incoherent vibration to a coherent
one when the atom-membrane coupling increases, agreeing with the experimental
observations. Our present study provides a simple way to study non-equilibrium
many-body physics that is complementary to ongoing experiments on the hybrid
atomic and opto-mechanical systems.

21
The categories of this paper are: adap-org
17
The categories of this paper are: q-fin
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga
20
The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
0
The categories of this paper are: hep-ph
5
The categories of this paper are: gr-qc
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
12
The categories of this paper are: nucl-th
14
The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess
2
The categories of this paper are: math