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arXiv · 0810.2655

Boundary effects on quantum q-breathers in a Bose-Hubbard chain

Ricardo A. Pinto·Jean Pierre Nguenang·Sergej Flach
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Abstract

We investigate the spectrum and eigenstates of a Bose-Hubbard chain containing two bosons with fixed boundary conditions. In the noninteracting case the eigenstates of the system define a two-dimensional normal-mode space. For the interacting case weight functions of the eigenstates are computed by perturbation theory and numerical diagonalization. We identify paths in the two-dimensional normal-mode space which are rims for the weight functions. The decay along and off the rims is algebraic. Intersection of two paths (rims) leads to a local enhancement of the weight functions. We analyze nonperturbative effects due to the degeneracies and the formation of two-boson bound states.

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Ricardo A. Pinto, Jean Pierre Nguenang, Sergej Flach. 2009-01-19. Boundary effects on quantum q-breathers in a Bose-Hubbard chain. https://doi.org/10.1016/j.physd.2008.12.013

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