Regensburg 2013 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 74: Focussed Session: Frontiers of Electronic Structure Theory VII (jointly with HL and TT)

O 74.1: Vortrag

Donnerstag, 14. März 2013, 16:00–16:15, H36

Determination of the one-body Green’s function: freedom and constraints — Giovanna Lani^1,4, •Pina Romaniello^2,4, and Lucia Reining^3,4 — ¹Forschungszentrum Jülich, Jülich, Germany — ²Laboratoire de Physique Théorique-IRSAMC, CNRS, Université Paul Sabatier, Toulouse, France — ³Laboratoire des Solides Irradiés, Ecole Polytechnique, CNRS, CEA-DSM, Palaiseau, France — ⁴European Theoretical Spectroscopy Facility (ETSF)

The one-particle Green’s function G plays a key role in many-body physics due to the wealth of physical information that it contains. In this work we go beyond the standard methods to calculate G, which are plagued by various shortcomings, and we use an approximate set of functional differential equations relating the one-particle Green’s function to its functional derivative with respect to an external perturbing potential [1]. We show that this set of equations has, in principle, multiple solutions, but that only one is well behaved - this is the physical solution. We give the formally exact family of solutions, which depends on an auxiliary quantity q, for which we find stringent exact constraints. Our findings suggest that once q is known, the physical solution is uniquely fixed by the vanishing Coulomb interaction limit [2-3].
[1] L. P. Kadanoff and G. Baym, Quantum Statistical Mechanics (W.A. Benjamin Inc., New York, 1964)
[2] G. Lani, P. Romaniello, and L. Reining, New Journal of Physics, 14, 013056 (2012)
[3] G. Lani, P. Romaniello, and L. Reining, in preparation