Absence of a Direct Superfluid to Mott Insulator Transition in Disordered Bose SystemsPhysics Review Letters
AbstractWe prove the absence of a direct quantum phase transition between a superfluid and a Mott insulator in a bosonic system with generic, bounded disorder. We also prove the compressibility of the system on the superfluid–insulator critical line and in its neighborhood. These conclusions follow from a general theorem of inclusions, which states that for any transition in a disordered system, one can always find rare regions of the competing phase on either side of the transition line. Quantum Monte Carlo simulations for the disordered Bose-Hubbard model show an even stronger result, important for the nature of the Mott insulator to Bose glass phase transition: the critical disorder bound Δc corresponding to the onset of disorder-induced superfluidity, satisfies the relation Δc>Eg/2, with Eg/2 the half-width of the Mott gap in the pure system.
Citation InformationL Pollet, N Prokof'ev, B Svistunov and Troyer. "Absence of a Direct Superfluid to Mott Insulator Transition in Disordered Bose Systems" Physics Review Letters Vol. 103 Iss. 14 (2009)
Available at: http://works.bepress.com/nikolai_prokofev/56/