Speaker
Description
We present an ab initio computation of the full nonequilibrium correction to the Wigner function of a generally interacting scalar field at freeze-out, assuming an initial state in local thermodynamic equilibrium within the framework of quantum statistical mechanics. In the hydrodynamic regime, we identify a previously overlooked dissipative memory term, proportional to the difference between the thermodynamic fields at local equilibrium and at decoupling. This contribution cannot be obtained by a direct application of standard Kubo formulas and encodes information about the system’s evolution prior to freeze-out. We then compute the corresponding nonequilibrium corrections to physical observables, such as the scalar-particle spectrum, and show that the memory term may have phenomenologically relevant effects in heavy-ion collisions and quark–gluon plasma evolution.
