Filling-fraction dependent emission in a matter-wave emitter array

Ultracold atoms in optical lattices realize a tunable open quantum system in the context of matter-wave emission into vacuum [1]. Previously, we observed deviations from single-particle dynamics in sparsely populated emitter arrays, due to atom reabsorption. Moreover, for arrays with large filling fractions, superradiant emission effects have been predicted [2]. We present an experimental investigation of the decay dynamics as a function of the filling fraction of the initial state in our optical lattice system. \newline \newline [1] L. Krinner, M. Stewart, A. Pazmiño, J. Kwon, D. Schneble, Spontaneous emission of matter waves from a tunable open quantum system, Nature 559, 589–592 (2018) \newline [2] de Vega, I., Porras, D. & Cirac, J. I. Matter-wave emission in optical lattices: single particle and collective effects. Phys. Rev. Lett. 101, 260404 (2008).