Instabilities in the Bogoliubov Spectrum of a condensate in a 1-D periodic potential

Jared C. Bronski; Zoi Rapti

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Instabilities in the Bogoliubov Spectrum of a condensate in a 1-D periodic potential

Jared C. Bronski·Zoi Rapti

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Abstract

We study the stability of standing wave solutions to a one-dimensional Gross-Pitaevsky equation with a periodic potential. We use some simple complex analysis and the Hamiltonian structure of the problem to give a simple rigorous criterion which guarantees the existence of non-real spectrum, which corresponds to exponential instability of the standing wave solution. This criterion can be stated simply in terms of the spectrum of one of these self-adjoint operators. When the standing wave has small amplitude this criterion simplifies further, and agrees with arguments based on the effective mass in the periodic potential.

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Jared C. Bronski, Zoi Rapti. 2005-04-12. Instabilities in the Bogoliubov Spectrum of a condensate in a 1-D periodic potential. https://arxiv.org/abs/cond-mat/0504304

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