Coupling between the motion of an electron or hole and its spin is a fundamental dynamical phenomenon in semiconductors. The spin-orbit coupling (SOC) is an essential ingredient in a number of prominent effects and applications in solids, such as the spin Hall and anomalous Hall effects, topological insulators/superconductors, spintronics, spin-based schemes for quantum computation, and others.
Recently, a great deal of interest has been drawn by possibilities of emulating SOC in cold-atom settings, induced by an appropriate combination of laser beams illuminating the atomic gas. In particular, these techniques are applicable both to atomic Bose-Einstein condensates (BECs) involving two different hyperfine internal states (quasi-spin 1/2 bosons) and also for the degenerate Fermi gases representing real spin 1/2 systems. When implemented for atomic bosons, such a SOC has no analogy with electrons in semiconductors, because the electrons are fermions. SOC of this kind was recently demonstrated experimentally in the USA and China. While SOC is, by itself, a linear effect, its interplay with the intrinsic collisional nonlinearity of the BEC was predicted to give rise to a number of novel states, such as striped ground states, tricritical points, solitons of various types, vortices and vortex lattices, and others. In atomic fermion gases SOC is expected to give rise to a variety of novel many-body quantum phases, such as topological fermionic superfluid, Fulde-Ferrell state featuring finite-momentum Cooper pairs, etc. All these issues are within the scope of the KITPC program.
In addition to already experimentally realized 1D SOC and the widely discussed 2D Rashba SOC, other types of SOC may also be achievable through the light-atom interactions. The generation and applications of new types of SOC for cold atoms will be among the topics of the KITPC Program. Furthermore, the spin in the SOC quantum gases need not be represented solely by atomic hyperfine states, other degrees of freedom, such as different orbital bands in optical lattices, being also usable for this purpose. In this context, the recent experimental progress in shaken optical lattices and higher-orbital-band optical lattices opens up a new platform for exploring exotic physics induced by the coupling between different lattice bands, where SOC can also be engineered.
The major objective of the KITPC Program is to bring together leading researchers in the field, who will focus on the progress in this rapidly developing area. In addition to the leading theorists, the Program will attract prominent experimentalists working on the SOC and related areas. This will help to stimulate the work on the realization of a new generation of experiments with SOC in Bose and Fermi gases, in which the many-body effects play an essential role.
It is planned to have an associated conference on the Synthetic Topological Quantum Matter, to be held on August 1-5, 2016 at the KITPC, Beijing (arrival day July 31, departure day August 5):