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.
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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 |
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Publication: | Europhysics Letters |
Publisher: | Institute of Physics |
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.ac.in/id/eprint/14856 |
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