Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nonlinear mode competition and symmetry-protected power oscillations in
  topological lasers   Topological photonics started out as a pursuit to engineer systems that mimic
fermionic single-particle Hamiltonians with symmetry-protected modes, whose
number can only change in spectral phase transitions such as band inversions.
The paradigm of topological lasing, realized in three recent experiments,
offers entirely new interpretations of these states, as they can be selectively
amplified by distributed gain and loss. A key question is whether such
topological mode selection persists when one accounts for the nonlinearities
that stabilize such systems at their working point. Here we show that
topological defect lasers can indeed stably operate in genuinely topological
states. These comprise direct analogues of zero modes from the linear setting,
as well as a novel class of states displaying symmetry-protected power
oscillations, which appear in a spectral phase transition when the gain is
increased. These effects show a remarkable practical resilience against
imperfections, even if these break the underlying symmetries, and pave the way
to harness the power of topological protection in nonlinear quantum devices.

34
The categories of this paper are: chem-ph
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
31
The categories of this paper are: ao-sci
4
The categories of this paper are: cond-mat
18
The categories of this paper are: econ
6
The categories of this paper are: astro-ph
15
The categories of this paper are: nucl-ex
12
The categories of this paper are: nucl-th
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
16
The categories of this paper are: stat
9
The categories of this paper are: nlin
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con