ABSTRACT
We demonstrate that multiply coupled spinor polariton condensates can be optically tuned through a sequence of spin-ordered phases by changing the coupling strength between nearest neighbors. For closed four-condensate chains these phases span from ferromagnetic (FM) to antiferromagnetic (AFM), separated by an unexpected crossover phase. This crossover phase is composed of alternating FM-AFM bonds. For larger eight-condensate chains, we show the critical role of spatial inhomogeneities and demonstrate a scheme to overcome them and prepare any desired spin state. Our observations thus demonstrate a fully controllable nonequilibrium spin lattice.
ABSTRACT
Tunable spin correlations are found to arise between two neighboring trapped exciton-polariton condensates which spin polarize spontaneously. We observe a crossover from an antiferromagnetic to a ferromagnetic pair state by reducing the coupling barrier in real time using control of the imprinted pattern of pump light. Fast optical switching of both condensates is then achieved by resonantly but weakly triggering only a single condensate. These effects can be explained as the competition between spin bifurcations and spin-preserving Josephson coupling between the two condensates, and open the way to polariton Bose-Hubbard ladders.
