Engineering Dresselhaus Spin-Orbit Coupling for Cold Atoms in a Double Tripod Configuration

摘要

We study laser induced spin-orbit (SO) coupling in cold atom systems where lasers couple three internal states to a pair of excited states, in a double tripod topology. Proper choice of laser amplitudes and phases produces a Hamiltonian with a doubly degenerate ground state separated from the remaining 'excited' eigenstates by gaps determined by the Rabi frequencies of the atom- light coupling. After eliminating the excited states with a Born-Oppenheimer approximation, the Hamiltonian of the remaining two states includes Dresselhaus (or equivalently Rashba) SO coupling. Unlike earlier proposals, here the SO coupled states are the two lowest energy 'dressed' spin states and are thus immune to collisional relaxation. Finally, we discuss a specific implementation of our system using Raman transitions between different hyperfine states within the electronic ground state manifold of nuclear spin I = 3/2 alkali atoms.