We study the ground state Ψ 0 =

icols2 2 We report our research on disordered complex systems using cold gases and trapped ions, and address the possibility of using complex systems for quantum information processing. Two simple paradigmatic models of disordered complex systems are revisited here. The first one corresponds to a short range disordered Ising Hamil-tonian (spin glasses), which can be implemented with a Bose-Ferm...

We produce Bose-Einstein condensates of 6Li2 molecules in a low power (22W) crossed optical dipole trap. Fermionic Li atoms are collected in a magnetooptical trap from a Zeeman slowed atomic beam, then loaded into the optical dipole trap where they are evaporatively cooled to quantum degeneracy. Our simplified system offers a high degree of flexibility in trapping geometry for studying ultracol...

We derive a upper bound on the free energy of a Bose gas system at density ̺ and temperature T . In combination with the lower bound derived previously by Seiringer [15], our result proves that in the low density limit, i.e., when a̺ ≪ 1, where a denotes the scattering length of the pair-interaction potential, the leading term of ∆f the free energy difference per volume between interacting and id...

In certain field theoretical models, composite solitons consisting of a domain wall and vortex lines attached to the wall have been referred to as 'D-brane solitons'. We show that similar composite solitons can be realized in phase-separated two-component Bose-Einstein condensates. We discuss the similarities and differences between topological solitons in the Abelian-Higgs model and those in t...

The question of whether the Bose-Einstein condensate ~BEC! is a necessary condition of the Meissner effect is examined. The electromagnetic susceptibility of a charged Bose gas with short-range repulsion is studied using the perturbation theory with respect to the repulsive force. With decreasing temperature, the Bosestatistical coherence grows, and prior to the BEC phase the susceptibility sho...

We investigate thermodynamic properties of noninteracting charged bosons in the presence of externally applied electric and magnetic "elds. Using the semiclassical density of states, we obtain the condensate fraction, chemical potential, total energy, and speci"c heat of a system of "nite number of charged Bose particles. We conclude that Bose}Einstein condensation of the charged Bose gas occur...

We probe the transition between superfluid and Bose glass phases using quantum quenches of disorder in an ultracold atomic lattice gas that realizes the disordered Bose-Hubbard model. Measurements of excitations generated by the quench exhibit threshold behavior in the disorder strength indicative of a phase transition. Ab-initio quantum Monte Carlo simulations confirm that the appearance of ex...

It has been known since the rigorous result by Angelescu and Corciovei [A-C] that the answer to the question in the title is negative for the Perfect Bose Gas (PBG). The main result of the present paper is that the answer could become positive if the bosons are simultaneously embedded in a periodic external potential. We show that it is true for PBG, as well as for the Bose gas with a mean-fiel...