Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Polar liquid crystals in two spatial dimensions: the bridge from
  microscopic to macroscopic modeling   Two-dimensional polar liquid crystals have been discovered recently in
monolayers of anisotropic molecules. Here, we provide a systematic theoretical
description of liquid-crystalline phases for polar particles in two spatial
dimensions. Starting from microscopic density functional theory, we derive a
phase-field-crystal expression for the free-energy density which involves three
local order-parameter fields, namely the translational density, the
polarization, and the nematic order parameter. Various coupling terms between
the order-parameter fields are obtained which are in line with macroscopic
considerations. Since the coupling constants are brought into connection with
the molecular correlations, we establish a bridge from microscopic to
macroscopic modeling. Our theory provides a starting point for further
numerical calculations of the stability of polar liquid-crystalline phases and
is also relevant for modeling of microswimmers which are intrinsically polar.

37
The categories of this paper are: supr-con
34
The categories of this paper are: chem-ph
19
The categories of this paper are: eess
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
22
The categories of this paper are: chao-dyn
27
The categories of this paper are: comp-gas
33
The categories of this paper are: plasm-ph
18
The categories of this paper are: econ
25
The categories of this paper are: patt-sol
15
The categories of this paper are: nucl-ex
23
The categories of this paper are: solv-int
7
The categories of this paper are: hep-th
17
The categories of this paper are: q-fin
36
The categories of this paper are: cmp-lg
16
The categories of this paper are: stat