Abstract
Mixtures of Bose-Einstein condensates offer situations where the usually dominant mean-field energy can be reduced such that higher-order terms may play a dominant role in the equation of state. In this context, the case of two component coupled Bose-Einsteincondensates will be specifically addressed. First, large attractive effective three-body interactions can be engineered with striking consequences [1]. Second, the beyond-mean field energy is precisely measured and is shown to be modified as compared to the uncoupled case [2].
