Biomedical subjects

H J Korsch

Publications and source records attributed to H J Korsch.

4 recordsLinked to original sources

PubMed2005

Bloch oscillations of Bose-Einstein condensates: breakdown and revival.

We investigate the dynamics of Bose-Einstein condensates in a tilted one-dimensional periodic lattice within the mean-field (Gross-Pitaevskii) description. Unlike in the linear case the Bloch oscillations decay because of nonlinear dephasing. Pronounced revival phenomena are observed. These are analyzed in detail in terms of a simple integrable model constructed by an expansion in Wannier-Stark resonance states. We also briefly discuss the pulsed output of such systems for stronger static fields.

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PubMed2003

Quantum diffusion in a biased kicked Harper system.

Quantum diffusion in a biased kicked Harper system, modeling field-induced transport in superlattices, is studied for fully chaotic dynamics of the underlying classical system. Under these conditions, the classical transport is diffusive whereas the quantum diffusion can be either enhanced or suppressed for commensurable or incommensurable ratio of the Bloch period to the driving period, respectively. The quantum transport properties are related to the statistical properties of the quasienergy spectra as described by random matrix theory.

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PubMed2001

Wannier-Stark states of a quantum particle in 2D lattices.

A simple method of calculating the Wannier-Stark resonances in 2D lattices is suggested. Using this method we calculate the complex Wannier-Stark spectrum for a nonseparable 2D potential realized in optical lattices and analyze its general structure. The dependence of the lifetime of Wannier-Stark states on the direction of the static field (relative to the crystallographic axis of the lattice) is briefly discussed.

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PubMed1999

Lifetime statistics for a Bloch particle in ac and dc fields.

We study the statistics of the Wigner delay time and resonance width for a Bloch particle in ac and dc fields in the regime of quantum chaos. It is shown that after appropriate rescaling the distributions of these quantities have a universal character predicted by the random matrix theory of chaotic scattering.

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