New method for studying steady states in quantum impurity problems: the interacting resonant level model

Doyon, Benjamin

Abstract

We develop a new perturbative method for studying any steady states of quantum impurities, in or out of equilibrium. We show that steady-state averages are completely fixed by basic properties of the steady-state (Hershfield's) density matrix along with dynamical "impurity conditions". This gives the full perturbative expansion without Feynman diagrams (matrix products instead are used), and "re-sums" into an equilibrium average that may lend itself to numerical procedures. We calculate the universal current in the interacting resonant level model (IRLM) at finite bias V to first order in Coulomb repulsion U for all V and temperatures. We find that the bias, like the temperature, cuts off low-energy processes. In the IRLM, this implies a power-law decay of the current at large V (also recently observed by Boulat and Saleur at some finite value of U).

Citation

Doyon, B. (2007). New method for studying steady states in quantum impurity problems: the interacting resonant level model. Physical Review Letters, 99(7), https://doi.org/10.1103/physrevlett.99.076806

• Journal Article Type: Article
• Publication Date: Aug 17, 2007
• Deposit Date: Jan 9, 2009
• Journal: Physical Review Letters
• Print ISSN: 0031-9007
• Electronic ISSN: 1079-7114
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 99
• Issue: 7
• DOI: https://doi.org/10.1103/physrevlett.99.076806
• Public URL: https://durham-repository.worktribe.com/output/1558694