Transport equations for the quark-gluon plasma

摘要

We are studying transport equations for the quark-gluon plamsa based on the exact Wigner representation as applied to various soliton models of quark confinment (or quasi-confinement). In broad outline, two major issues are addressed: (i) the transprot of quarks once they exist within a soliton field, and (ii) the initial production of quark-antiquark pairs from a pre-existing chromoelectric field by means of the Schwinger mechanism. In the first context, we develop coupled transport equations to describe quarks moving in a soliton field and discuss our preliminary efforts towards solving such equations. In connection with pair production in a chromoelectric field, we first point out certain inadequacies in the transport-equation approach for problems that, of necessity, require full quantal and relativistic treatment; these difficulties have importatn implications for the entire program of applying transport equations to the quark-gluon plasma (or to relativistic nuclear matter in certain contexts). We then note that other problems enter in trying to address a boost-invariant picture of the plasma even from a field-theory point of view. As a result, we turn to formulations of pair production in homogeneous but time-varying chromoelectric fields in the hope of gaining insight into how the Schwinger mechanism might be modified in such circumstances.