Quantum phase transitions of hard-core bosons in background potentials.
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.
Priyadarshee
Anand
A
Department of Physics, Box 90305, Duke University, Durham, North Carolina 27708-0305, USA.
Chandrasekharan
Shailesh
S
Lee
Ji-Woo
JW
Baranger
Harold U
HU