Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Symbiotic two-component gap solitons   We consider a two-component one-dimensional model of gap solitons (GSs),
which is based on two nonlinear Schr\"odinger equations, coupled by repulsive
XPM (cross-phase-modulation) terms, in the absence of the SPM
(self-phase-modulation) nonlinearity. The equations include a periodic
potential acting on both components, thus giving rise to GSs of the "symbiotic"
type, which exist solely due to the repulsive interaction between the two
components. The model may be implemented for "holographic solitons" in optics,
and in binary bosonic or fermionic gases trapped in the optical lattice.
Fundamental symbiotic GSs are constructed, and their stability is investigated,
in the first two finite bandgaps of the underlying spectrum. Symmetric solitons
are destabilized, including their entire family in the second bandgap, by
symmetry-breaking perturbations above a critical value of the total power.
Asymmetric solitons of intra-gap and inter-gap types are studied too, with the
propagation constants of the two components falling into the same or different
bandgaps, respectively. The increase of the asymmetry between the components
leads to shrinkage of the stability areas of the GSs. Inter-gap GSs are stable
only in a strongly asymmetric form, in which the first-bandgap component is a
dominating one. Intra-gap solitons are unstable in the second bandgap. Unstable
two-component GSs are transformed into persistent breathers. In addition to
systematic numerical considerations, analytical results are obtained by means
of an extended ("tailed") Thomas-Fermi approximation (TFA).

6
The categories of this paper are: astro-ph
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
0
The categories of this paper are: hep-ph
37
The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
28
The categories of this paper are: alg-geom
27
The categories of this paper are: comp-gas
17
The categories of this paper are: q-fin
23
The categories of this paper are: solv-int
14
The categories of this paper are: math-ph
21
The categories of this paper are: adap-org
24
The categories of this paper are: dg-ga
7
The categories of this paper are: hep-th
11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics