Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Memory effects, arches and polar defect ordering at the cross-over from
  wet to dry active nematics   We use analytic arguments and numerical solutions of the continuum, active
nematohydrodynamic equations to study how friction alters the behaviour of
active nematics. Concentrating on the case where there is nematic ordering in
the passive limit, we show that, as the friction is increased, memory effects
become more prominent and $+1/2$ topological defects leave increasingly
persistent trails in the director field as they pass. The trails are
preferential sites for defect formation and they tend to impose polar order on
any new $+1/2$ defects. In the absence of noise and for high friction, it
becomes very difficult to create defects, but trails formed by any defects
present at the beginning of the simulations persist and organise into parallel
arch-like patterns in the director field. We show aligned arches of equal width
are approximate steady state solutions of the equations of motion which
co-exist with the nematic state. We compare our results to other models in the
literature, in particular dry systems with no hydrodynamics, where trails,
arches and polar defect ordering have also been observed.

31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
7
The categories of this paper are: hep-th
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
27
The categories of this paper are: comp-gas
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
29
The categories of this paper are: funct-an
23
The categories of this paper are: solv-int
34
The categories of this paper are: chem-ph
17
The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
3
The categories of this paper are: physics
11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org