A topological ladder

The orbital degrees of freedom refer to different shapes of the wave functions with degenerate energies. In recent years, optical lattices engineered by interfering laser beams offer new means to explore interacting fermions with orbital degrees of freedom the symmetries of which differ from those found in traditional solids. We show that the orbital hopping pattern alone …

Phase diagram of dipolar Fermi gases


Understanding the quantum phases of interacting fermions is a fundamental, chanllenging problem in many-body physics. Broken symmetry phases, such as spin density wave order in antiferromagnetic metal Chromium, or the p-wave superfluid order in liquid Helium 3, have long been known and well understood. Motivated by recent experiments, we find theoretically that an unconventional spin-density wave phase with …

Erhai Zhao’s research interests

Many body physics of ultracold quantum gases

Ultracold gases refer to quantum degenerate gases of atoms (such as Rubidium, Potassium or Lithium) or molecules confined in vacuum by laser beams and cooled down to nano-Kelvin temperatures (one billionth degree above absolute zero). These systems offer well-controlled settings to test and advance our basic understanding of the collective behaviors of …