General Theory of Nonequilibrium Quantum Physics in Real Time

M. Guida

Jong E. Han, Andreas Dirks, Thomas Pruschke

We discuss the formal relationship between the real-time Keldysh and imaginary-time theory for nonequilibrium in quantum dot systems. The latter can be reformulated using the recently proposed Matsubara-voltage approach. We establish general conditions for correct analytic continuation procedure on physical observables, and apply the technique to the calculation of static quantities in steady-state nonequilibrium for a quantum dot subject to a finite bias voltage and external magnetic field. Limitations of the Matsubara voltage approach are also pointed out.

Paweł Danielewicz

Burgess

Quasiparticle descriptions of nonequilibrium physics hold the promise of tracking the relevant degrees of freedom in calculations of statistical systems, as well as providing an important formal perspective on quantum field theories away from equilibrium.A formulation of nonequilibrium, quasiparticle field theory is presented here.The Schwinger closed time path generating functional and generalized sources are used to develop schematic field theories which can be adapted to real problems.The importance of the source method for effective nonequilibrium theories is argued and the physical interpretation of the formalism is discussed, including its possible applicability to biological dynamics.

P. Danielewicz. Nuclear Science Division