Related papers: Excitations of a trapped two component Bose Einste…
Motivated by recent experiments on Faraday waves in Bose Einstein condensates (BEC) we investigate the dynamics of two component cigar shaped BEC subject to periodic modulation of the strength of the transverse confinement. It is shown that…
We discuss BEC in (quasi)2D trapped gases and find that well below the transition temperature $T_c$ the equilibrium state is a true condensate, whereas at intermediate temperatures $T<T_c$ one has a quasicondensate (condensate with…
We consider a two-component immiscible Bose-Einstein condensate with dominating intra-species repulsive density-density interactions. In the ground-state phase of such a system only one condensates is present. This can be viewed as a…
The excitation spectrum of a two-component Bose-Einstein condensate has been discussed by Ref \cite{alex2comp} using the Bogoliubov equations. Here we make the additional contributions of the linear response function and dielectric function…
The collapsing dynamics of a trapped Bose-Einstein condensate (BEC) with attractive interaction are revealed to exhibit two previously unknown phenomena. During the collapse, BEC undergoes a series of rapid implosions that occur {\it…
We study the interference effects between three weakly linked trapped Bose-Einstein condensates (BEC) as a generalization of the two-component condensates. Three coupled Gross-Pitaevskii equations (GPE) are used to describe the dynamics of…
The system under consideration is a multi-component gas of interacting para- and orthoexcitons confined in a three dimensional potential trap. We calculate the spatially resolved optical emission spectrum due to interband transitions…
The miscibility of two interacting quantum systems is an important testing ground for the understanding of complex quantum systems. Two-component Bose-Einstein condensates enable the investigation of this scenario in a particularly well…
We investigate experimentally a Bose Einstein condensate placed in a 1D optical lattice whose phase or amplitude is modulated in a frequency range resonant with the first bands of the band structure. We study the combined effect of the…
A unique feature of multi-component BECs is the possibility of beating frequencies in collective oscillations. We analytically determine this beating frequency for the two-component BEC in one-dimension. We also show that the Thomas-Fermi…
We study the excitation spectrum of the two-chain S=1/2 Heisenberg spin ladder with additional inter-chain second-neighbor frustrating interactions. The one and two-particle excitations are analyzed by using a mapping of the model onto a…
We report on measurements of the excitation spectrum of a strongly interacting Bose-Einstein condensate (BEC). A magnetic-field Feshbach resonance is used to tune atom-atom interactions in the condensate and to reach a regime where quantum…
Combining two Bose-Einstein condensates (BECs) may result in a miscible or immiscible mixture, or even a violent implosion. We theoretically demonstrate that dipolar two-component BECs produce far richer physics than their nondipolar…
We demonstrate the existence of phase fluctuations in elongated Bose-Einstein Condensates (BECs) and study the dependence of those fluctuations on the system parameters. A strong dependence on temperature, atom number, and trapping geometry…
The excitation spectrum and the band structure of a Bose-Einstein condensate in a periodic potential are investigated. Analyses within full 3D systems, finite 1D systems, and ideal periodic 1D systems are compared. We find two branches of…
A mixture of two distinguishable Bose-Einstein condensates confined in a ring potential has numerous interesting properties under rotational and solitary-wave excitation. The lowest-energy states for a fixed angular momentum coincide with a…
We have studied the effects of a disordered optical potential on the transport and phase coherence of a Bose-Einstein condensate (BEC) of 7Li atoms. At moderate disorder strengths (V_D), we observe inhibited transport and damping of dipole…
The collective excitation of hybrid atomic-molecular condensate are studied using variational method. The dipole response of the system is studied in detail. We found that the out-of-phase dipole oscillation frequency increasing slowly with…
The excitation spectrum of a highly-condensed two-dimensional trapped Bose-Einstein condensate (BEC) is investigated within the rotating frame of reference. The rotation is used to transfer high-lying excited states to the low-energy…
We calculate the number and energy densities of a quasi-2D Bose-Einstein gas constrained within a thin region of infinite extent but of finite width d. The BEC critical transition temperature then becomes an explicit function of d. We use…