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Finite size scaling in crossover among different random matrix ensembles in microscopic lattice models

Modak, Ranjan and Mukerjee, Subroto (2014) Finite size scaling in crossover among different random matrix ensembles in microscopic lattice models. In: NEW JOURNAL OF PHYSICS, 16 .

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Official URL: http://dx.doi.org/10.1088/1367-2630/16/9/093016


Using numerical diagonalization we study the crossover among different random matrix ensembles (Poissonian, Gaussian orthogonal ensemble (GOE), Gaussian unitary ensemble (GUE) and Gaussian symplectic ensemble (GSE)) realized in two different microscopic models. The specific diagnostic tool used to study the crossovers is the level spacing distribution. The first model is a one-dimensional lattice model of interacting hard-core bosons (or equivalently spin 1/2 objects) and the other a higher dimensional model of non-interacting particles with disorder and spin-orbit coupling. We find that the perturbation causing the crossover among the different ensembles scales to zero with system size as a power law with an exponent that depends on the ensembles between which the crossover takes place. This exponent is independent of microscopic details of the perturbation. We also find that the crossover from the Poissonian ensemble to the other three is dominated by the Poissonian to GOE crossover which introduces level repulsion while the crossover from GOE to GUE or GOE to GSE associated with symmetry breaking introduces a subdominant contribution. We also conjecture that the exponent is dependent on whether the system contains interactions among the elementary degrees of freedom or not and is independent of the dimensionality of the system.

Item Type: Journal Article
Additional Information: Copyright for this article belongs to the IOP PUBLISHING LTD, TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND.
Keywords: thermalization; disorder; random matrix theory; spin-orbit coupling
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 08 Nov 2014 05:06
Last Modified: 08 Nov 2014 05:06
URI: http://eprints.iisc.ac.in/id/eprint/50162

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