Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Fine Structure of the Phonon in One Dimension from Quantum
  Hydrodynamics   We show that the resonant interactions between phonons in one dimension may
be treated consistently within Quantum Hydrodynamics by the introduction of
phonon dispersion. In this way the physics of a nonlinear Luttinger liquid may
be described in terms of hydrodynamic (i.e. bosonized) variables without
recourse to refermionization or the introduction of fictitious impurities.
  We focus on the calculation of the dynamic structure factor for a model with
quadratic dispersion, which has the Benjamin--Ono equation of fluid dynamics as
its equation of motion. We find singular behavior in the vicinity of upper and
lower energetic thresholds corresponding to phonon and soliton branches of the
classical theory, which may be benchmarked against known results for the
Calogero--Sutherland model.

10
The categories of this paper are: q-bio
35
The categories of this paper are: mtrl-th
19
The categories of this paper are: eess
18
The categories of this paper are: econ
13
The categories of this paper are: quant-ph
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
6
The categories of this paper are: astro-ph
21
The categories of this paper are: adap-org
33
The categories of this paper are: plasm-ph
37
The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs
5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph