Particle production by expanding in the future light cone scalar quantum field is studied by assuming that the initial state is associated with the quasiequilibrium statistical operator corresponding to fluid dynamics. We calculate particle production from a longitudinally boost-invariant expanding quantum field designed as a simple but reliable model for the central rapidity region of a relativistic collision. Exact diagonalization of the model is performed by introducing a notion of quasiparticles.

• Received 2 September 2020
• Accepted 26 May 2021

DOI:https://doi.org/10.1103/PhysRevD.103.116014

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Published by the American Physical Society