Seminar ÚFKL: Jiří Chaloupka (habilitation talk)

Department of Condensed Matter Physics (ÚFKL) invites you to the lecture

Jiří Chaloupka (habilitation talk):
Investigation of strongly correlated electron systems by means of exact diagonalization techniques

In the field of strongly correlated electrons, exact diagonalization (ED) is traditionally one of the most frequently used numerical tools to study effective models. At the conceptual level, it is appealingly simple: the Hamiltonian of the system is represented by a large matrix in a convenient basis and numerically diagonalized, typically by Lanczos method, obtaining thereby the ground state and excited states. Having these states at hand, any quantity of interest can be evaluated, in some cases even the internal structure of the states can be analyzed. All this information is exact without any bias which makes the method very attractive. The price one has to pay is the limitation to small clusters so that finite-size effects have to be carefully considered. In the lecture, I will show the basic principles of ED and demonstrate an application of this method to a spin system with bond-selective anisotropic interactions. Apart from the analysis of the ground-state properties, I will also briefly cover the extensions of ED to probe the dynamics of the system and to handle finite temperatures.