SEMINAR: Dr. Jovan Odavić

You are cordially invited to the SCL seminar of the Center for the Study of Complex Systems, which will be held on Thursday, 12 September 2019 at 14:00 in the library reading room “Dr. Dragan Popović” of the Institute of Physics Belgrade. The talk entitled

Density oscillations of one-dimensional correlated electron systems from DFT

will be given by Dr. Jovan Odavić (Institute for Theory of Statistical Physics, RWTH Aachen University; Peter-Grünberg Institute and Institute for Advanced Simulation, Forschungszentrum Jülich, Germany).

Abstract of the talk:

Gapless quasi-one-dimensional systems are not described by the Fermi liquid theory, as is the case with interacting systems in higher dimensions, but rather by another unique framework, the Luttinger liquid theory. In this talk we will focus on strongly correlated one-dimensional Luttinger liquid physics [1]. In particular, we will try to bridge the gap between what is known from field theoretical methods, such as bosonization, and the real physical systems that are fabricated in the laboratory. Beyond weak interactions this gap is wider than most theorist imagine and experimentalist would like. By starting from microscopic models, we will investigate whether methods such as the Kohn-Sham Density Functional Theory (KS DFT), in conjunction with the Local Density Approximation (LDA) for the exchange-correlation potential, can provide a correct description of the underlying Luttinger liquid low-energy fixed point.

Basic theorems of KS DFT guarantee that the KS ground state charge density matches the density of the fully interacting many-body system if the exchange-correlation potential is exact. Therefore, we focus exclusively on the oscillations, known as Friedel oscillations, that occur in the density in presence of a boundary (or an infinitely strong impurity). The power-law decay of the Friedel oscillations, away from the boundary and into the bulk, represents one of the hallmarks of the Luttinger liquid paradigm. We will use the Hartree-Fock approximation to investigate this decay and propose a method to compute the density based on the Matsubara Green’s functions. We will also clarify the limitations of LDA in describing Luttinger liquids.

[1] J. Odavić, N. Helbig, and V. Meden, arXiv:1906.07066 (2019).