Enrico Arrigoni
Institute of Theoretical and Computational Physics
Graz University of Technology, Graz, Austria
Abstract: Among the various numerical techniques to study the physics of strongly correlated quantum many-body systems, Variational Cluster Approach (VCA) has become increasingly important. This method combines cluster calculations with variational procedures with the goal of extending the results to the thermodynamic limit. This talk discusses two extensions of this method. In the first one we deal with strongly-correlated lattice bosons in the condensed superfluid phase. To this end, we reformulate the method within a so-called "pseudoparticle" formalism, whereby cluster excited states are described in terms of particle-like excitations. Calculations for the two-dimensional Bose-Hubbard model show excellent agreement with Quantum Monte-Carlo results.
In the second part we discuss the Keldysh Green's function extension of VCA, which allows to compute nonequilibrium steady state properties of strongly correlated quantum many-body systems. As an illustration, we apply the approach to study non-linear transport across a strongly correlated quantum wire described by the fermionic Hubbard model.
Location: 606 conference room
Date and time: August 18th, 2011 10:30 A.M.
Introduction to speaker:
1) Master at the University of Pisa, Italy in 1989
2) PhD at Scuola Normale Superiore, Pisa in 1993
3) Postdoc at the Max-Planck Institute in Stuttgart, Germany 1994-1995
4) Postdoc and research assistant at the University of Wuerzburg, Germany 1995-2003
5) 2001: Habilitation in Theoretical Physics
6) Since 2003: Professor of Theoretical and Computational Physics at the Graz University of Technology, Graz, Austria
7) Visiting scientist at Stanford University, University of California at Los Angeles, and the University of Geneva
Main present and past Research activities:
High-Temperature Superconductors,
One- and quasi-one dimensional systems (Luttinger liquids)
Half Metallic Ferromagnets
Correlated Systems out of Equilibrium
Ultracold bosonic atoms in otical lattices and correlated ligh-matter systems
Development of cluster numerical methods to treat strongly-correlated systems.
