LAUSR

Particle production by expanding in the future light cone scalar quantum field is studied by assuming that the initial state is associated with the quasi equilibrium statistical operator corresponding to fluid dynamics. We calculate particle production from longitudinally boost-invariant expanding quantum field designed as a simple but reliable model for the central rapidity region of a relativistic collision. We perform exact diagonalization of the model by introducing a notion of quasiparticles and define a zero-temperature instantaneous ground state for the quasi equilibrium statistical operator. Adiabatic regularization of the particle production due to the ground state decay is discussed.