Discrete breathers in Bose-Einstein condensates

Roberto Franzosi, Roberto Livi, Gian-Luca Oppo, Antonio Politi

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

Discrete breathers, originally introduced in the context of biopolymers and coupled nonlinear oscillators, are also localized modes of excitation of Bose-Einstein condensates (BEC) in periodic potentials such as those generated by counter-propagating laser beams in an optical lattice. Static and dynamical properties of breather states are analysed in the discrete nonlinear Schrodinger equation that is derived in the limit of deep potential wells, tight-binding and the superfluid regime of the condensate. Static and mobile breathers can be formed by progressive re-shaping of initial Gaussian wave-packets or by transporting atomic density towards dissipative boundaries of the lattice. Static breathers generated via boundary dissipations are determined via a transfer-matrix approach and discussed in the two analytic limits of highly localized and very broad profiles. Mobile breathers that move across the lattice are well approximated by modified analytical expressions derived from integrable models with two independent parameters: the core-phase gradient and the peak amplitude. Finally, possible experimental realizations of discrete breathers in BEC in optical lattices are discussed in the presence of residual harmonic trapping and in interferometry configurations suitable to investigate discrete breathers' interactions.

Original languageEnglish
Pages (from-to)R89-R122
Number of pages34
JournalNonlinearity
Volume24
Issue number12
DOIs
Publication statusPublished - Dec 2011

Keywords

  • mean-field theory
  • optical lattices
  • coupled oscillators
  • nonlinear lattices
  • Hubbard-model
  • quantum gases
  • dynamics
  • arrays
  • solitons
  • transition

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