By means of Monte Carlo techniques, we study the role of disorder on a system of hard-core bosons in a two-leg ladder with both intrachain ( t ) and interchain ( t ′ ) hoppings. We find that the phase diagram as a function of the boson density, disorder strength, and t ′ / t is far from being trivial. This contrasts with the case of spinless fermions where standard localization arguments apply and an Anderson-localized phase pervades the whole phase diagram. A compressible Bose-glass phase always intrudes between the Mott insulator with zero (or one) bosons per site and the superfluid that is stabilized for weak disorder. At half-filling, there is a direct transition between a (gapped) rung-Mott insulator and a Bose glass, which is driven by exponentially rare regions where disorder is suppressed. Finally, by doping the rung-Mott insulator, a direct transition to the superfluid is possible only in the clean system, whereas the Mott phase is always surrounded by the a Bose glass when disorder is present. The phase diagram based on our numerical evidence is finally reported.

Bose-glass, superfluid, and rung-Mott phases of hard-core bosons in disordered two-leg ladders / Carrasquilla, J.; Becca, F.; Fabrizio, M.. - In: PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS. - ISSN 1098-0121. - 83:24(2011), pp. 245101.1-245101.7. [10.1103/PhysRevB.83.245101]

Bose-glass, superfluid, and rung-Mott phases of hard-core bosons in disordered two-leg ladders

Becca, F.;Fabrizio, M.
2011-01-01

Abstract

By means of Monte Carlo techniques, we study the role of disorder on a system of hard-core bosons in a two-leg ladder with both intrachain ( t ) and interchain ( t ′ ) hoppings. We find that the phase diagram as a function of the boson density, disorder strength, and t ′ / t is far from being trivial. This contrasts with the case of spinless fermions where standard localization arguments apply and an Anderson-localized phase pervades the whole phase diagram. A compressible Bose-glass phase always intrudes between the Mott insulator with zero (or one) bosons per site and the superfluid that is stabilized for weak disorder. At half-filling, there is a direct transition between a (gapped) rung-Mott insulator and a Bose glass, which is driven by exponentially rare regions where disorder is suppressed. Finally, by doping the rung-Mott insulator, a direct transition to the superfluid is possible only in the clean system, whereas the Mott phase is always surrounded by the a Bose glass when disorder is present. The phase diagram based on our numerical evidence is finally reported.
2011
83
24
1
7
245101
https://arxiv.org/abs/1102.3339
Carrasquilla, J.; Becca, F.; Fabrizio, M.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/16168
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