The role of average time dependence on the relaxation of excited electron populations in nonequilibrium many‐body physics

Journal Article · Mon Aug 22 00:00:00 EDT 2016 · Fortschritte der Physik

DOI:https://doi.org/10.1002/prop.201600042· OSTI ID:1401700

Kemper, A. F. ^[1]; Krishnamurthy, H. R. ^[2]; Freericks, J. K. ^[3]

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1. Department of Physics North Carolina State University Raleigh North Carolina 27695 USA
2. Department of Physics Indian Institute of Science Bangalore‐560012 India
3. Department of Physics Georgetown University 37th and O Sts. NW, Washington District of Columbia 20057‐1789 USA

We examine the exact equation of motion for the relaxation of populations of strongly correlated electrons after a nonequilibrium excitation by a pulsed field, and prove that the populations do not change when the Green's functions have no average time dependence. We show how the average time dependence enters into the equation of motion to lowest order and describe what governs the relaxation process of the electron populations in the long‐time limit. While this result may appear, on the surface, to be required by any steady‐state solution, the proof is nontrivial, and provides new critical insight into how nonequilibrium populations relax, which goes beyond the assumption that they thermalize via a simple relaxation rate determined by the imaginary part of the self‐energy, or that they can be described by a quasi‐equilibrium condition with a Fermi‐Dirac distribution and a time‐dependent temperature. We also discuss the implications of this result to approximate theories, which may not satisfy the exact relation in the equation of motion.

• Sponsoring Organization: USDOE
• OSTI ID: 1401700
• Journal Information: Fortschritte der Physik, Journal Name: Fortschritte der Physik Vol. 65 Journal Issue: 6-8; ISSN 0015-8208
• Publisher: Wiley Blackwell (John Wiley & Sons)
• Country of Publication: Germany
• Language: English