Non-Hermitian spin-orbit-coupled quantum gases

While spin-orbit coupling (SOC), an essential mechanism underlying quantum phenomena from the spin Hall effect to topological insulators, has been widely studied in well-isolated Hermitian systems, much less is known when the dissipation plays a major role in spin-orbit-coupled quantum systems. Here I will briefly report our realization of non-Hermitian spin-orbit couplings in platforms ranging from bulk to optical lattices. First, I will discuss the  observation of  the exceptional point (EP) in a bulk non-Hermitian system with spin-orbit coupling. This topological feature of the realized EP  enables us to tune SOC and dissipation dynamically in the parameter space, and observe the state evolution is direction- dependent near the EP, revealing chiral spin transfer between different quantum states when the quantum state encircles the EP. Secondly, I will briefly report our recent development on the non-Hermitian lattice with spin-orbit coupling, in which exceptional points show up with the Dirac Fermi arc. In this system, we observe the evidence for the 2D non-Hermitian skin effect by measuring the eigen-energy spectrum.