Related papers: Suppression of superfluidity by dissipation -- An …
We study the boundary nature of trapped bosonic Mott insulators in optical square lattices, by performing quantum Monte Carlo simulation. We show that a finite superfluid density generally emerges in the incommensurate-filling (IC) boundary…
We introduce a new renormalization group theory to examine the quantum phase transitions upon exiting the insulating phase of a disordered, strongly interacting boson system. For weak disorder we find a direct transition from this Mott…
The emergence of a compressible insulator phase, known as the Bose glass, is characteristic of the interplay of interactions and disorder in correlated Bose fluids. While widely studied in tight-binding models, its observation remains…
We consider interacting Bose particles in an external potential. It is shown that a Bose-Einstein condensate is possible at finite temperatures that describes a supersolid in three dimensions (3D) for a wide range of potentials in the…
We show that the suppression of light scattering off a Bose Einstein Condensate is equivalent to the Landau argument for superfluidity and thus is a consequence of the {\it Principle of Superfluidity}. The superfluid ground state of a BEC…
We study Mott insulator - superfluid transition in a two-band boson Hubbard model, which can be mapped onto a spin-1/2 XY model with spins coupled to an additional Ising degree of freedom. By using a modified mean field theory that include…
A self-consistent model of the superfluid (SF) state of a Bose liquid with strong interaction between bosons is considered, in which at T=0, along with a weak single-particle Bose-Einstein condensate (BEC), there exists an intensive pair…
We investigate the Bose glass phase and the insulator-to-superfluid transition in the two-dimensional disordered boson Hubbard model in the Villain representation via Monte Carlo simulations. In the Bose glass phase the probability…
We report on results of Quantum Monte Carlo simulations for bosons in a two dimensional quasi-periodic optical lattice. We study the ground state phase diagram at unity filling and confirm the existence of three phases: superfluid, Mott…
We numerically investigate the phase diagram of two-dimensional site-diluted coupled dimer systems in an external magnetic field. We show that this phase diagram is characterized by the presence of an extended Bose glass, not accessible to…
General field theory of a fluctuating d-wave superconductor is constructed and proposed as an effective description of superconducting cuprates at low energies. The theory is used to resolve a puzzle posed by recent experiments on…
We consider two-dimensional dipolar bosonic gas with dipoles oriented perpendicularly to the plane in a weak random potential. We investigate analytically and numerically the condensate depletion, the one-body density-matrix, the ground…
Josephson weak links in superconductors can be engineered such that the phase difference across the junction is $\pi$ ($\pi$-junction),leading to the reversal of the current. The conditions under which the analogous effect of supercurrent…
For many years, $^4$He typified Bose-Einstein superfluids, but recent advances in dilute ultra-cold alkali-metal gases have provided new neutral superfluids that are particularly tractable because the system is dilute. This chapter starts…
Superfluidity---the suppression of scattering in a quantum fluid at velocities below a critical value---is one of the most striking manifestations of the collective behaviour typical of Bose-Einstein condensates. This phenomenon, akin to…
We study the Mott insulator-superfluid transition of ultracold bosonic atoms in a two-dimensional square optical lattice in the presence of a synthetic magnetic field with p/q (p and q being co-prime integers) flux quanta passing through…
The phase diagram of a single component Bose system in a lattice at zero temperature is obtained. We calculate the variational energies for the Mott insulating and superfluid phases. Below a certain critical density, which depends…
In the quantum rotor model with random exchange interactions having a non-zero mean, three phases, a 1) phase (Bose) glass, 2) superfluid, and 3) Mott insulator, meet at a bi-critical point. We demonstrate that proximity to the bi-critical…
One of the most spectacular properties associated with Bose-Einstein condensation (BEC) is superfluidity in which the system exhibits zero viscosity and flows without dissipation. The superfluid phase has been observed in wide ranging…
We study the superfluid-insulator transition in a one dimensional system of interacting bosons, modeled as a disordered Josephson array, using a strong randomness real space renormalization group technique. Unlike perturbative methods, this…