Eur. Phys. J. B (2014) 87: 66
https://doi.org/10.1140/epjb/e2014-50028-2

Regular Article

Linear response within the projector-based renormalization method: many-body corrections beyond the random phase approximation

¹ Institute of Research and Development, Duy Tan University, K7/25 Quang Trung, Danang, Vietnam
² Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald, Germany
³ Institut für Theoretische Physik, Technische Universität Dresden, 01062 Dresden, Germany

^a e-mail: klaus.w.becker@tu-dresden.de

Received: 13 January 2014
Received in final form: 12 February 2014
Published online: 12 March 2014

Abstract

The explicit evaluation of linear response coefficients for interacting many-particle systems still poses a considerable challenge to theoreticians. In this work we use a novel many-particle renormalization technique, the so-called projector-based renormalization method, to show how such coefficients can systematically be evaluated. To demonstrate the prospects and power of our approach we consider the dynamical wave-vector dependent spin susceptibility of the two-dimensional Hubbard model and also determine the subsequent magnetic phase diagram close to half-filling. We show that the superior treatment of (Coulomb) correlation and fluctuation effects within the projector-based renormalization method significantly improves the standard random phase approximation results.