[institut] SCL seminar: Faraday waves in BECs, Antun Balaz, petak 24. maj u 14:00

[Nenad Vukmirovic]

Postovane koleginice i kolege,

Pozivam vas na SCL seminar koji ce u petak 24. maja 2013. godine u 14:00 
u citaonici Instituta za fiziku odrzati Antun Balaz (SCL, Institut za 
fiziku u Beogradu). Naslov seminara i apstrakt su dati u nastavku ove 
poruke.

Nonlinear Excitations in Bose-Einstein Condensates: Faraday Waves

Abstract:

In addition to collective oscillation modes, Bose-Einstein Condensates 
(BECs) exhibit a number of other excitations due to their inherent 
nonlinearity. Faraday (density) waves can be generated by a periodic 
modulation of the trapping potential or atomic interactions, and were 
first observed experimentally in 2007. Using the results of extensive 
numerical simulations and analytical variational calculations, we will 
show that elongated binary non-miscible BECs subject to periodic 
modulations of the radial confinement exhibit a Faraday instability 
similar to that seen in one-component condensates. Considering the 
hyperfine states of 87Rb condensates, we will show that there are two 
experimentally relevant stationary state configurations: the one in 
which the components form a dark-bright symbiotic pair (the ground state 
of the system), and the one in which the components are segregated 
(first excited state).

For each of these two configurations, we will numerically demonstrate 
that far from resonances the Faraday waves excited in the two BEC 
components are of similar periods, emerge simultaneously, and do not 
impact the dynamics of the bulk of the condensate. We will also 
analytically derive the period of the Faraday waves using a variational 
treatment of the coupled Gross-Pitaevskii equations combined with a 
Mathieu-type analysis for the selection mechanism of the excited waves. 
Finally, we will show that for a modulation frequency close to twice 
that of the radial trapping, the emergent surface waves fade out in 
favor of a forceful collective mode that turns the two BEC components 
miscible.

Srdacan pozdrav,

-- 
Dr Nenad Vukmirovic,
Visi naucni saradnik,
Laboratorija za primenu racunara u nauci,
Institut za fiziku Beograd,
Srbija.
URL: http://www.scl.rs/nenad