Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 94: Correlated Electrons: Other Theoretical Topics
TT 94.12: Vortrag
Donnerstag, 15. März 2018, 18:15–18:30, H 3010
Conditions where RPA becomes exact in the high-density limit — •Klaus Morawetz1,2,3, Vinod Ashokan4, Renu Bala5, and Kare Narain Pathak4 — 1Münster University of Applied Sciences,Stegerwaldstrasse 39, 48565 Steinfurt, Germany — 2International Institute of Physics- UFRN,Campus Universitário Lagoa nova,59078-970 Natal, Brazil — 3Max-Planck-Institute for the Physics of Complex Systems, 01187 Dresden, Germany — 4Centre for Advanced Study in Physics, Panjab University, 160014 Chandigarh, India — 5Department of Physics, MCM DAV College for Women, 160036 Chandigarh, India
It is shown that in d-dimensional systems, the vertex corrections beyond the random phase approximation (RPA) or GW approximation scales with the power d−β−α of the Fermi momentum if the relation between Fermi energy and Fermi momentum is єf∼ pfβ and the interacting potential possesses a momentum-power-law of ∼ p−α. The condition d<β+α specifies systems where RPA is exact in the high-density limit. The one-dimensional structure factor is found to be the interaction-free one in the high-density limit. A cancellation of RPA and vertex corrections render this result alternatively valid up to second-order contact interaction. For finite-range potentials of cylindrical wires a large-scale cancellation appears and found to be independent of the width parameter. The proposed high-density expansion agrees with diffusive Monte Carlo simulations which we performed for this purpose.