Superfluidity of trapped quantum systems in two and three dimensions

We analyze the superfluid crossover of harmonically confined bosons with long-range interaction in both two and three dimensions in a broad parameter range from weak to strong coupling. We observe that the onset of superfluidity occurs in three dimensions at significantly lower temperatures compared to that in two dimensions. This is demonstrated to be a quantum degeneracy effect. In addition, the spatial distribution of superfluidity across the shells of the clusters is investigated. It is found that superfluidity is substantially reduced in the outer layers due to increased correlation effects.We analyze the superfluid crossover of harmonically confined bosons with long-range interaction in both two and three dimensions in a broad parameter range from weak to strong coupling. We observe that the onset of superfluidity occurs in three dimensions at significantly lower temperatures compared to that in two dimensions. This is demonstrated to be a quantum degeneracy effect. In addition, the spatial distribution of superfluidity across the shells of the clusters is investigated. It is found that superfluidity is substantially reduced in the outer layers due to increased correlation effects.

arXiv:1410.0878Physical Review BFeb 3, 201524 citations

Superfluidity of Two–Dimensional and One–Dimensional Systems

WORLD SCIENTIFIC eBooksNov 1, 20090 citations

Superfluid to normal phase transition in strongly correlated bosons in two and three dimensions

Juan Carrasquilla, Marcos Rigol

Using quantum Monte Carlo simulations, we investigate the finite-temperature phase diagram of hard-core bosons ( $XY$ model) in two- and three-dimensional lattices. To determine the phase boundaries, we perform a finite-size-scaling analysis of the condensate fraction and/or the superfluid stiffness. We then discuss how these phase diagrams can be measured in experiments with trapped ultracold gases, where the systems are inhomogeneous. For that, we introduce a method based on the measurement of the zero-momentum occupation, which is adequate for experiments dealing with both homogeneous and trapped systems, and compare it with previously proposed approaches.Using quantum Monte Carlo simulations, we investigate the finite-temperature phase diagram of hard-core bosons ($XY$ model) in two- and three-dimensional lattices. To determine the phase boundaries, we perform a finite-size-scaling analysis of the condensate fraction and/or the superfluid stiffness. We then discuss how these phase diagrams can be measured in experiments with trapped ultracold gases, where the systems are inhomogeneous. For that, we introduce a method based on the measurement of the zero-momentum occupation, which is adequate for experiments dealing with both homogeneous and trapped systems, and compare it with previously proposed approaches.

arXiv:1205.6484Physical Review AOct 26, 201237 citations

Superfluidity in trapped Bose-Einstein condensates

Chao Feng, Matthew J. Davis

Jan 1, 20090 citations

Quench from Mott insulator to superfluid

Jacek Dziarmaga, Marek Tylutki, Wojciech Hubert Zurek

We study a linear ramp of the nearest-neighbor tunneling rate in the Bose-Hubbard model driving the system from the Mott insulator state into the superfluid phase. We employ the truncated Wigner approximation to simulate linear quenches of a uniform system in one, two, and three dimensions, and in a harmonic trap, in three dimensions. In all these setups, the excitation energy decays like one over third root of the quench time. The $\ensuremath{-}1/3$ scaling arises from an impulse-adiabatic approximation---a variant of the Kibble-Zurek mechanism---describing a crossover from nonadiabatic to adiabatic evolution when the system begins to keep pace with the increasing tunneling rate.We study a linear ramp of the nearest-neighbor tunneling rate in the Bose-Hubbard model driving the system from the Mott insulator state into the superfluid phase. We employ the truncated Wigner approximation to simulate linear quenches of a uniform system in one, two, and three dimensions, and in a harmonic trap, in three dimensions. In all these setups, the excitation energy decays like one over third root of the quench time. The $\ensuremath{-}1/3$ scaling arises from an impulse-adiabatic approximation---a variant of the Kibble-Zurek mechanism---describing a crossover from nonadiabatic to adiabatic evolution when the system begins to keep pace with the increasing tunneling rate.

arXiv:1206.1067Physical Review BOct 17, 201225 citations

Using quantum Monte Carlo simulations, we investigate the finite-temperature phase diagram of hard-core bosons (

XY

model) in two- and three-dimensional lattices. To determine the phase boundaries, we perform a finite-size-scaling analysis of the condensate fraction and/or the superfluid stiffness. We then discuss how these phase diagrams can be measured in experiments with trapped ultracold gases, where the systems are inhomogeneous. For that, we introduce a method based on the measurement of the zero-momentum occupation, which is adequate for experiments dealing with both homogeneous and trapped systems, and compare it with previously proposed approaches.