Collisional spin transfer in an atomic heteronuclear spinor Bose gas

Abstract

We observe spin transfer within a nondegenerate heteronuclear spinor atomic gas comprising a small ^{7}Li population admixed with a ^{87}Rb bath, with both elements in their F=1 hyperfine spin manifolds. Prepared in a nonequilibrium initial state, the ^{7}Li spin distribution evolves through incoherent spin-changing collisions toward a steady-state distribution. We identify and measure the cross sections of all three types of spin-dependent heteronuclear collisions, namely the spin-exchange, spin-mixing, and quadrupole-exchange interactions, and find agreement with predictions of heteronuclear ^{7}Li-^{87}Rb interactions at low energy. Moreover, we observe that the steady state of the ^{7}Li spinor gas can be controlled by varying the composition of the ^{87}Rb spin bath with which it interacts.