Quantum phase transitions and coherent tunneling in a bilayer of ultracold atoms with dipole interactions

Abstract

We study the quantum phase transitions and coherent tunneling in bilayer ultracold bosonic atoms with dipolar interactions at total filling factor ν T = 1/2. We demonstrate that, due to the unique characters of the dipole interactions, the ground state of the system may undergo paired quantum Hall state (PQH), dimer quantum-Hall state (DQH), and super-counter-fluidity phase (SCF) by tuning the dipole strength. The SCF state which breaks the easy-plane U(1) symmetry is of particular interest because it can exhibit interlayer coherent tuneling in the incompressible quantum-Hall (QH) state. We suggest that this coherent tunneling current could be observed directly in future experiments.