Universität zu Köln

Pinheiro, Fernanda and Larson, Jonas (2015). Disordered cold atoms in different symmetry classes. Phys. Rev. A, 92 (2). COLLEGE PK: AMER PHYSICAL SOC. ISSN 1094-1622

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Abstract

We consider an experimentally realizable model of noninteracting but randomly coupled atoms in a two-dimensional optical lattice. By choosing appropriate real or complex-valued random fields and species-dependent energy offsets, this system can be used to analyze effects of disorder in four different symmetry classes: the chiral BDI and AIII and the nonchiral A and AI. These chiral classes are known to support a metallic phase at zero energy, which here, due to the inevitable finite size of the system, should also persist in a neighborhood of nonzero energies. As we discuss, this is of particular interest for experiments involving quenches. Away from the center of the spectrum, we find that excitations appear as domain walls in the cases with time-reversal symmetry or as vortices in the cases where time-reversal symmetry is absent. Therefore, a quench in a system with uniform density would lead to the formation of either vortices or domain walls depending on the symmetry class. For the nonchiral models in classes A and AI, a population imbalance between the two atomic species naturally occurs. In these cases, one of the two species is seen to favor a more uniform density. We also study the onset of localization as the disorder strength is increased for the different classes, and by deriving an effective model for the nonchiral cases we show how their eigenstates remain extended for larger values of the coupling with the disorder when compared to the nonchiral ones.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Pinheiro, Fernanda UNSPECIFIED UNSPECIFIED UNSPECIFIED Larson, Jonas UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-396537
DOI:	10.1103/PhysRevA.92.023612
Journal or Publication Title:	Phys. Rev. A
Volume:	92
Number:	2
Date:	2015
Publisher:	AMER PHYSICAL SOC
Place of Publication:	COLLEGE PK
ISSN:	1094-1622
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language METAL-INSULATOR-TRANSITION; RANDOM MAGNETIC-FIELD; ANDERSON LOCALIZATION; MOBILITY EDGE; RANDOM FLUX; ABSENCE; SYSTEM; LATTICES Multiple languages Optics; Physics, Atomic, Molecular & Chemical Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/39653