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Maximum group velocity in a one-dimensional model with a sinusoidally varying staggered potential

Nag, Tanay and Sen, Diptiman and Dutta, Amit (2015) Maximum group velocity in a one-dimensional model with a sinusoidally varying staggered potential. In: PHYSICAL REVIEW A, 91 (6).

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Official URL: http://dx.doi.org/ 10.1103/PhysRevA.91.063607


We use Floquet theory to study the maximum value of the stroboscopic group velocity in a one-dimensional tight-binding model subjected to an on-site staggered potential varying sinusoidally in time. The results obtained by numerically diagonalizing the Floquet operator are analyzed using a variety of analytical schemes. In the low-frequency limit we use adiabatic theory, while in the high-frequency limit the Magnus expansion of the Floquet Hamiltonian turns out to be appropriate. When the magnitude of the staggered potential is much greater or much less than the hopping, we use degenerate Floquet perturbation theory; we find that dynamical localization occurs in the former case when the maximum group velocity vanishes. Finally, starting from an ``engineered'' initial state where the particles (taken to be hard-core bosons) are localized in one part of the chain, we demonstrate that the existence of a maximum stroboscopic group velocity manifests in a light-cone-like spreading of the particles in real space.

Item Type: Journal Article
Additional Information: Copy right for this article belongs to the AMER PHYSICAL SOC, ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
Department/Centre: Division of Physical & Mathematical Sciences > Centre for High Energy Physics
Date Deposited: 19 Jul 2015 06:08
Last Modified: 19 Jul 2015 06:08
URI: http://eprints.iisc.ac.in/id/eprint/51811

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