Characterisation of the dynamical quantum state of a zero temperature Bose–Einstein condensate

We describe the quantum state of a Bose–Einstein condensate at zero temperature. By evaluating theQ-function we show that the ground state of Bose–Einstein condensate under the Hartree approximation is squeezed.We find that multimode Schrödinger cat states are generated as the condensate evolves in a ballistic expansion.Peer reviewe