On nonequilibrium states in QFT model with boundary interaction

TL;DR

This paper demonstrates that specific nonequilibrium expectation values in the boundary sine-Gordon model match equilibrium expectation values in an extended system with additional boundary degrees of freedom, aiding in calculating nonequilibrium properties.

Contribution

It establishes a correspondence between nonequilibrium and equilibrium expectation values in the boundary sine-Gordon model with added boundary degrees of freedom.

Findings

Nonequilibrium expectation values match equilibrium values in an extended model.

Application to calculating nonequilibrium characteristics of the boundary sine-Gordon model.

Provides a method to simplify nonequilibrium analysis in boundary QFT models.

Abstract

We prove that certain nonequilibrium expectation values in the boundary sine-Gordon model coincide with associated equilibrium-state expectation values in the systems which differ from the boundary sine-Gordon in that certain extra boundary degrees of freedom (q-oscillators) are added. Applications of this result to actual calculation of nonequilibrium characteristics of the boundary sine-Gordon model are also discussed.