Publications (22)
Ultracold bosons in lattices with binary disorder
K. V. Krutitsky, M. Thorwart, R. Egger +1
Quantum phases of ultracold bosons with repulsive interactions in lattices in the presence of quenched disorder are investigated. The disorder is assumed to be caused by the intera…
First- and second-order superfluid--Mott-insulator phase transitions of spin-1 bosons with coupled ground states in optical lattices
K. V. Krutitsky, M. Timmer, R. Graham
We investigate the superfluid--Mott-insulator quantum phase transition of spin-1 bosons in an optical lattice created by pairs of counterpropagating linearly polarized laser beams,…
Phase preparation by atom counting of Bose-Einstein condensates in mixed states
R. Graham, T. Wong, M. J. Collett +2
We study the build up of quantum coherence between two Bose-Einstein condensates which are initially in mixed states. We consider in detail the two cases where each condensate is i…
Collapses and Revivals of Collective Excitations in Trapped Bose Condensates
R. Graham, D. F. Walls, M. J. Collett +2
We present a quantum theory of low-lying excitations in a trapped Bose condensate with finite particle numbers. We find that even at zero temperature condensate number fluctuations…
Spin-1 bosons with coupled ground states in optical lattices
K. V. Krutitsky, R. Graham
The superfluid--Mott-insulator phase transition of ultracold spin-1 bosons with ferromagnetic and antiferromagnetic interactions in an optical lattice is theoretically investigated…
Supersymmetric Homogeneous Quantum Cosmologies Coupled to a Scalar Field
J. Bene, R. Graham
Recent work on supersymmetric Bianchi type IX cosmologies coupled to a scalar field is extended to a general treatment of homogeneous quantum cosmologies with explicitely sol…