【直播】【江苏省青年物理学家论坛】强关联量子霍尔体系中的量子相变

Quantum Hall states are prototypical examples of topological phases. They were initially discovered in two-dimensional electron gases and have generated widespread interest in many other areas. The advances in cold atoms create novel settings for studying topological states that would be quite difficult in solid state systems. One example is that the constituents of quantum gases can be different types of bosons, fermions, and their mixtures. We propose a variety of invertible topological states and symmetry-protected topological states in two-dimensional Bose-Fermi mixtures using the composite fermion theory. These states have no fractionalized excitations but possess gapless edge states. In certain continuum and lattice models, we can induce continuous quantum phase transitions between these states and some fractional quantum Hall states by tuning the inter-species interaction. The critical theory of these transitions are Chern-Simons-Higgs field theory in which the condensation of a scalar boson field leads to “locking” of a pair of emergent gauge fields.

编辑：吴良秀