Strong interaction effects and criticality of bosons in shaken optical lattices.
We study the quantum phase transitions and identify a tricritical point between a normal Bose superfluid, a superfluid that breaks additional Z(2) Ising symmetry, and a Mott insulator in a recent shaken optical lattice experiment. We show that near the transition between normal and Z(2) symmetry breaking superfluids, bosons can condense into a momentum state with high or even locally maximum kinetic energies due to the interaction effect. We present a general low-energy effective field theory that treats both the superfluid transition and the Ising transition in a uniform framework. Using the perturbative renormalization group method, we find that the critical behavior of the quantum phase transition belongs to a universality class different from that of a dilute Bose gas.
Institute for Advanced Study, Tsinghua University, Beijing 100084, China.
Wei
W
Zheng
Institute for Advanced Study, Tsinghua University, Beijing 100084, China.
Boyang
B
Liu
Institute for Advanced Study, Tsinghua University, Beijing 100084, China.
Jiao
J
Miao
James Franck Institute, Enrico Fermi Institute and Department of Physics, University of Chicago, Chicago, Illinois 60637, USA.
Cheng
C
Chin
Institute for Advanced Study, Tsinghua University, Beijing 100084, China.
Hui
H
Zhai