Discrete breathers in Bose-Einstein condensates

Year: 2011

Authors: Franzosi R., Livi R., Oppo G. L., Politi A.

Autors Affiliation: Istituto dei Sistemi Complessi, Consiglio Nazionale delle Ricerche, via Madonna del Piano 10 Sesto Fiorentino, I-50019, Italy; Dipartimento di Fisica, Università di Firenze and INFN, Sez. di Firenze, Via G. Sansone 1, Sesto Fiorentino, I-50019, Italy; Institute of Complex Systems, SUPA and Department of Physics, University of Strathclyde, 107 Rottenrow, Glasgow G4 ONG, Scotland, UK; College of Physical Sciences, King\’s College, University of Aberdeen, Aberdeen AB24 3UE, Scotland, UK

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.

Journal/Review: NONLINEARITY

Volume: 24 (12)      Pages from: R89  to: R122

More Information: RF thanks the ESF Exchange Grant support within the activity \’Quantum Degenerate Dilute Systems\’. G-LO acknowledges support from the ICS at Strathclyde and the EU network grant HIDEAS.
KeyWords: breathers; Bose-Einstein condensates; discrete nonlinear Schroedinger equatio; mean-field theory; optical lattices
DOI: 10.1088/0951-7715/24/12/R01

Citations: 37
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