Stochastic spin flips in polariton condensates: Nonlinear tuning from GHz to sub-Hz

The stability of spin of macroscopic quantum states to intrinsic noise is studied for non-resonantly pumped optically-trapped polariton condensates. We demonstrate flipping between the two spinpolarised states with >10⁴ slow-down of the flip rate by tuning the optical pump power. Individual spin flips faster than 50 picosecond are time resolved using single-shot streak camera imaging. We reproduce our results within a mean-field model accounting for cross-spin scattering between excitons and polaritons, yielding a ratio of cross- to co-spin scattering of ~0.6, in contrast with previous literature suggestions.
ERC LINASS 320503. Leverhulme Trust Grant No. VP1-2013-011. Bilateral Greece-Russia “Polisimulator” project co-financed by Greece and the EU Regional Development Fund. Stavros Niarchos Foundation, “ARCHERS” project. Horizon 2020 programme (No. FETPROACT-2016 732894-HOT). CONACYT (Mexico) grant No. 251808. Institute for Basic Science in Korea (IBS-R024-D1)