Critical fluctuations of an attractive Bose gas in a double well potential (no molecules here) Marek Trippenbach, with B. Malomed, P. Ziń, J. Chwedeńczuk, B. Oleś, K. Sacha, Ngien Viet Hung, M. Matuszewski, J. Gocałek EUROQUAM SATELLITE MEETING ON COLD AND ULTRACOLD MOLECULES
Plan Introducing CIGMA and BEC collisions BEC in double well Effects of higher dimensions Instability during collisions
Elastic collisions
BEC collision – the experiment A. Perrin et al. PRL 99, (2007) 2-nd order corelation
Theoretical model for collision Hamiltonian Bogoliubov approximation Condensate wave-function
Spontaneous versus Stimulated P. Ziń et al., Phys. Rev Lett. 94, (2005) J. Chwedeńczuk et al., Phys. Rev. Lett. 97, (2006) P. Ziń, J. Chwedeńczuk and M. Trippenbach, Phys. Rev. A 73, (2006)
Equations of motion the condensate: Gross-Pitaevskii Equation field of scattered atoms: time-dependent Bogoliubov approximation small 1st order perturbation theory
Theory versus experiment Close momenta opposite momenta
BEC in 1D double well by Markus Oberhaler
Experiment: Double well structure Markus Oberthaler, 2005
Oberthaler data
Why are we surprized: linear case
Linear case: tunneling only
Mean Field Approach
Energy diagram
Phase Space Dynamics
Dynamics
Two body interactions: Hamiltonian Introducing interactions Noninteracting particles … Localized states
Schrodinger Equation … and approximation
Continuum approximation Effective one dimensional equation
Effective potential
Fluctuations … can be done even in the repulsive case, if multicomponent
Wigner Function
BEC in double well effects of higher dimensions
Two channel potential
Hysteresis
Two channel solitons
Gap solitons
Two channel potential + lattice
Two channel potentail + lattice
Experimental Proposal: Hysteresis Wieslaw Krolikowski Pawel Zin Jan Chwedenczuk
Experimental Proposal: Collisions Nguen Viet Hung Pawel Zin Czesław Radzewicz