From thermal equilibrium to nonequilibrium quench dynamics: A conserving approximation for the interacting resonant level

Abstract

We develop a low-order conserving approximation for the interacting resonant-level model (IRLM), and apply it to (i) thermal equilibrium, (ii) nonequilibrium steady state, and (iii) nonequilibrium quench dynamics. Thermal equilibrium is first used to carefully gauge the quality of the approximation by comparing the results with other well-studied methods, and finding good agreement for small values of the interaction. We analytically show that the power-law exponent of the renormalized level width usually derived using renormalization group approaches can also be correctly obtained in our approach in the weak interaction limit. A closed expression for the nonequilibrium steady-state current is derived and analytically and numerically evaluated. We find a negative differential conductance at large voltages, and the exponent of the power-law suppression of the steady-state current is calculated analytically at zero-temperature. The response of the system to quenches is investigated for a single-lead as well as for two-lead setup at finite voltage bias at particle-hole symmetry using a self-consistent two-times Keldysh Green function approach, and results are presented for the time-dependent current for different bias and contact interaction strength.

References in corpus (9)

• The density-matrix renormalization group in the age of matrix product states
• The numerical renormalization group method for quantum impurity systems
• Twofold advance in the theoretical understanding of far-from-equilibrium properties of interacting nanostructures
• Exact low temperature results for transport properties of the interacting resonant level model
• Strong enhancement of transport by interaction on contact links
• Hybrid NRG-DMRG approach to real-time dynamics of quantum impurity systems
• Quench dynamics of correlated quantum dots
• On the applicability of bosonization and the Anderson-Yuval methods at the strong-coupling limit of quantum impurity problems
• Strong-to-weak-coupling duality in the nonequilibrium interacting resonant-level model

Cited by in corpus (2)

• Out-of-equilibrium dynamics in a quantum impurity model: numerics for particle transport and entanglement entropy
• Non-equilibrium Green's functions and their relation to the negative differential conductance in the interacting resonant level model