Affinity for scalar fields to dissipate - art. no. 103509

The zero-temperature effective equation of motion is derived for a scalar h eld interacting with other fields. For a broad range of cases, involving in teraction with as few as one or two fields, dissipative regimes are found f or the scalar field system. The zero-temperature limit constitutes a baseli ne effect that will be prevalent in any general statistical state. Thus, th e results found here provide strong evidence that dissipation is the norm n ot the exception for an interacting scalar field system. For application to inflationary cosmology, this provides convincing evidence that warm inflat ion could be a natural dynamics once proper treatment of the interactions i s done. The results found here also may have applicability to entropy produ ction during the chiral phase transition in heavy-ion collision.