Collisional spin transfer in an atomic heteronuclear spinor Bose gas

We observe spin transfer within a non-degenerate heteronuclear spinor atomic gas comprised of a small \(^7\)Li population admixed with a \(^{87}\)Rb bath, with both elements in their \(F=1\) hyperfine spin manifolds and at temperatures of 10's of \(\mu\)K. Prepared in a non-equilibrium 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.