Quantum spin mixing in a binary mixture of spin-1 atomic condensates

We study quantum spin mixing in a mixture of two spin-1 condensates including coherent interspecies mixing processes, using condensates of Rb-87 and Na-23 atoms in the ground lower hyperfine F = 1 manifold as prototype examples. Adopting the single spatial mode approximation for each of the two spinor condensates, we find the mixing dynamics reduce to that of three coupled nonrigid pendulums with clear physical interpretation. With suitably prepared initial states, the spin mixing dynamics allow for the determination of interspecies singlet-pairing as well as spin-exchange interaction parameters.