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SUMMARY:Parametric and Geometric Resonances of Collective Oscillation Mode
 s in Bose-Einstein Condensates
DTSTART;VALUE=DATE-TIME:20110830T152000Z
DTEND;VALUE=DATE-TIME:20110830T154000Z
DTSTAMP;VALUE=DATE-TIME:20261013T035701Z
UID:indico-contribution-366-322@indico.ipb.ac.rs
DESCRIPTION:Speakers: Antun Balaž (IPB)\nIn this paper we analytically an
 d numerically study nonlinear dynamics in Bose-Einstein condensates induce
 d by a harmonic modulation of the interaction\nand by geometry of the trap
 ping potential. To analytically describe BEC dynamics\, we use perturbativ
 e expansion based on the Poincaré-Lindstedt\nanalysis of a Gaussian varia
 tional ansatz\, while in the numerical approach we use numerical solutions
  of a variational system of equations and of the full time-dependent Gross
 -Pitaevskii equation. Harmonic modulation of the atomics-wave scattering l
 ength a Bose-Einstein condensate of Li was achieved recently via Feshbach 
 resonance. Such modulation leads to a number of nonlinear effects\, which 
 we describe within our approach: mode couplin g\, higher harmonics generat
 ion and significant shifts in the frequencies of collective modes. In part
 icular\, analytic formulae for shifts in the frequencies of collective mod
 es are derived and verified numerically for the case of spherically and ax
 ially symmetric condensates. In addition to the strength of atomic interac
 tions in BEC\, geometry of the trapping potential is another key factor fo
 r the dynamics of the condensate\, as well as for its collective oscillati
 on modes. The asymmetry of the confining potential leads to important nonl
 inear effects\, including the 57 resonances in the frequencies of collecti
 ve oscillation modes of the condensate [6]. We study in detail such geomet
 ric resonances and derive explicit analytic results for frequency shifts f
 or the case of axially symmetric condensate with 2-body and 3-body interac
 tions. Analytically obtained results are verified by extensive numerical s
 imulations.\n\nhttps://events.saifa.rs/event/366/contributions/322/
LOCATION:Kolarac building
URL:https://events.saifa.rs/event/366/contributions/322/
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