Abstract
We determine the dynamical critical exponent appearing at the Bose glass to superfluid transition in two dimensions by performing large scale numerical studies of two microscopically different quantum models within the universality class: The hard-core boson model and the quantum rotor (soft core) model, both subject to strong on-site disorder. By performing many simulations at different system size and inverse temperature close to the quantum critical point, the position of the critical point and the critical exponents, , , and can be determined independently of any implicit assumptions of the numerical value of , in contrast to most prior studies. This is done by a careful scaling analysis close to the critical point with a particular focus on the temperature dependence of the scaling functions. For the hard-core boson model we find , , and with a critical field of , while for the quantum rotor model we find , , and with a critical hopping parameter of . In both cases do we find a correlation length exponent consistent with , saturating the bound as well as a value of significantly larger than previous studies, and for the quantum rotor model consistent with .
- Received 23 January 2015
DOI:https://doi.org/10.1103/PhysRevLett.114.255701
© 2015 American Physical Society