Issue
EPL
Volume 84, Number 6, December 2008
Article Number 67001
Number of page(s) 5
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
DOI http://dx.doi.org/10.1209/0295-5075/84/67001
Published online 13 November 2008
EPL, 84 (2008) 67001
DOI: 10.1209/0295-5075/84/67001

A many-body approach to quantum transport dynamics: Initial correlations and memory effects

P. Myöhänen1, A. Stan1, G. Stefanucci2, 3 and R. van Leeuwen1, 3

1   Department of Physics, Nanoscience Center, University of Jyväskylä - FIN 40014, Jyväskylä, Finland, EU
2   Dipartimento di Fisica, Università di Roma Tor Vergata - Via della Ricerca Scientifica 1, I-00133 Rome, Italy, EU
3   European Theoretical Spectroscopy Facility (ETSF)

roleeuwe@jyu.fi

received 21 October 2008; accepted in final form 5 November 2008; published December 2008
published online 13 November 2008

Abstract
We study time-dependent quantum transport through a correlated double quantum dot (DQD) model system by means of time propagation of the nonequilibrium many-body Green's function. The theory is an extension of the Kadanoff-Baym approach for finite inhomogeneous systems (Phys. Rev. Lett., 98 (2007) 153004) to open inhomogeneous systems and generalizes the Meir-Wingreen formula to include initial correlations and memory effects. Important features of the theory are 1) the possibility to study the ultrafast dynamics of transients and other time-dependent regimes and 2) the inclusion of exchange and correlation effects in a conserving approximation scheme. We calculate time-dependent local currents and densities for different many-body approximations and highlight the role of initial correlations and memory effects on the transient dynamics. Furthermore we show that coherent charge oscillations on the DQD are strongly affected by the confined Coulomb interaction and can be directly related to the local equilibrium spectral density.

PACS
72.10.Bg - General formulation of transport theory.
71.10.-w - Theories and models of many-electron systems.
73.63.-b - Electronic transport in nanoscale materials and structures.

© EPLA 2008