ePrints@IIScePrints@IISc Home | About | Browse | Latest Additions | Advanced Search | Contact | Help

Superfluid and Insulating Phases in an Interacting-Boson Model: Mean-Field Theory and the RPA

Sheshadri, K and Krishnamurthy, HR and Pandit, R and Ramakrishnan, TV (1993) Superfluid and Insulating Phases in an Interacting-Boson Model: Mean-Field Theory and the RPA. In: Europhysics Letters, 22 (4). pp. 257-263.

[img] PDF
ramesh.pdf
Restricted to Registered users only

Download (483Kb) | Request a copy

Abstract

The bosonic Hubbard model is studied via a simple mesn-field theory. At zero temperature, in addition to yielding a phase diagram that is qualitatively correct, namely a superfluid phase for non-integer fillings and a Mott transition from a superfluid to an insulating phase for integer fillings, this theory gives results that are in good agreement with Monte Carlo simulations. In particular, the superfluid fraction obtained as a function of the interaction strength U for both integer and non-integer fillings is close to the simulation results. In all phases the excitation spectra are obtained by using the random phase approximation (RPA): the spectrum has a gap in the insulating phase and is gapless (and linear at small wave vectors) in the superfluid phase. Analytic results are presented in the limits of large U and small superfluid density. Finite-temperature phase diagrams and the Motbinsulator-normal-phase crossover are also descriied.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to Institute of Physics.
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 08 Jul 2008
Last Modified: 19 Sep 2010 04:47
URI: http://eprints.iisc.ernet.in/id/eprint/14856

Actions (login required)

View Item View Item