Non-Equilibrium Quantum Dissipation

Abstract

Dissipative processes in non-equilibrium many-body systems are fundamentally different than their equilibrium counterparts. Such processes are of great importance for the understanding of relaxation in single molecule devices. As a detailed case study, we investigate here a generic spin-fermion model, where a two-level system couples to two metallic leads with different chemical potentials. We present results for the spin relaxation rate in the nonadiabatic limit for an arbitrary coupling to the leads, using both analytical and exact numerical methods. The non-equilibrium dynamics is reflected by an exponential relaxation at long times and via complex phase shifts, leading in some cases to an "anti-orthogonality" effect. In the limit of strong system-lead coupling at zero temperature we demonstrate the onset of a Marcus-like Gaussian decay with {\it voltage difference} activation. This is analogous to the equilibrium spin-boson model, where at strong coupling and high temperatures the spin excitation rate manifests temperature activated Gaussian behavior. We find that there is no simple linear relationship between the role of the temperature in the bosonic system and a voltage drop in a non-equilibrium electronic case. The two models also differ by the orthogonality-catastrophe factor existing in a fermionic system, which modifies the resulting lineshapes. Implications for current characteristics are discussed. We demonstrate the violation of pair-wise Coulomb gas behavior for strong coupling to the leads. The results presented in this paper form the basis of an exact, non-perturbative description of steady-state quantum dissipative systems.

References in corpus (14)

• Molecular Transport Junctions: Vibrational Effects
• Observation of the two-channel Kondo effect
• Nonequilibrium Transport in Quantum Impurity Models (Bethe-Ansatz for open systems)
• Nonequilibrium quantum criticality in open electronic systems
• Scaling and Decoherence in the Out-of-Equilibrium Kondo Model
• Universal aspects of non-equilibrium currents in a quantum dot
• Nonequilibrium Transport through a Kondo Dot in a Magnetic Field: Perturbation Theory
• Nonequilibrium Transport through a Kondo Dot: Decoherence Effects
• Fermi-Edge Resonance and Tunneling in Nonequilibrium Electron Gas
• Semiclassical analysis of the Nonequilibrium Local Polaron
• Coulomb Gas on the Keldysh Contour: Anderson-Yuval-Hamann representation of the Nonequilibrium Two Level System
• Spin dynamics and violation of the fluctuation dissipation theorem in a non-equilibrium ohmic spin boson model
• Response of a Fermi gas to time-dependent perturbations: Riemann-Hilbert approach at non-zero temperatures
• Fermi Edge Singularities in the Mesoscopic Regime: I. Anderson Orthogonality Catastrophe

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