01281nas a2200109 4500008004100000245007800041210006900119520088200188100002901070700002401099856004801123 2018 en d00aEffective non-linear spinor dynamics in a spin-1 Bose-Einstein condensate0 aEffective nonlinear spinor dynamics in a spin1 BoseEinstein cond3 aWe derive from first principles the experimentally observed effective dynamics of a spinor Bose gas initially prepared as a Bose–Einstein condensate and then left free to expand ballistically. In spinor condensates, which represent one of the recent frontiers in the manipulation of ultra-cold atoms, particles interact with a two-body spatial interaction and a spin–spin interaction. The effective
dynamics is well-known to be governed by a system of coupled semi-linear Schrödinger equations: we recover this system, in the sense of marginals in the limit of infinitely many particles, with a mean-field re-scaling of the manybody Hamiltonian. When the resulting control of the dynamical persistence of condensation is quantified with the parameters of modern observations, we obtain a bound that remains quite accurate for the whole typical duration of the experiment.1 aMichelangeli, Alessandro1 aOlgiati, Alessandro uhttp://preprints.sissa.it/handle/1963/35311