title: Quantum phase transitions of hard-core bosons in background potentials.
abstract: We study the zero temperature phase diagram of hard-core bosons in two dimensions subjected to three types of background potentials: staggered, uniform, and random. In all three cases there is a quantum phase transition from a superfluid (at small potential) to a normal phase (at large potential), but with different universality classes. As expected, the staggered case belongs to the XY universality, while the uniform potential induces a mean field transition. The disorder driven transition is clearly different from both; in particular, we find z approximately 1.4, nu approximately 1, and beta approximately 0.6.
authors.affiliation: Department of Physics, Box 90305, Duke University, Durham, North Carolina 27708-0305, USA.
authors.forename: Anand
authors.initials: A
authors.lastname: Priyadarshee
authors.forename: Shailesh
authors.initials: S
authors.lastname: Chandrasekharan
authors.forename: Ji-Woo
authors.initials: JW
authors.lastname: Lee
authors.forename: Harold U
authors.initials: HU
authors.lastname: Baranger