Eur. Phys. J. B (2012) 85: 266
https://doi.org/10.1140/epjb/e2012-30303-0

Regular Article

Defining the effective temperature of a quantum driven system from current-current correlation functions

Departamento de Física, FCEyN, Universidad de Buenos Aires, Pabellón 1, Ciudad Universitaria, 1428 Buenos Aires, Argentina

^a e-mail: lili@df.uba.ar

Received: 10 April 2012
Received in final form: 30 May 2012
Published online: 1 August 2012

Abstract

We calculate current-current correlation functions and find an expression for the zero-frequency noise of multiterminal systems driven by harmonically time-dependent voltages within the Keldysh non-equilibrium Green’s functions formalism. We also propose a fluctuation-dissipation relation for current-current correlation functions to define an effective temperature. We discuss the behavior of this temperature and compare it with the local temperature determined by a thermometer and with the effective temperature defined from a single-particle fluctuation-dissipation relation. We show that for low frequencies all the definitions of the temperature coincide.