Stuttgart 2012 – wissenschaftliches Programm
Q 22.3: Vortrag
Dienstag, 13. März 2012, 11:15–11:30, V7.03
Perturbative calculation of critical exponents for the Bose-Hubbard model — •Dennis Hinrichs1, Axel Pelster2, and Martin Holthaus1 — 1Institut für Physik, Carl von Ossietzky Universität Oldenburg, 26111 Oldenburg — 2Hanse-Wissenschaftskolleg, 27753 Delmenhorst
The process-chain approach is a powerful tool for carrying out perturbative calculations for many-body lattice systems in high order of the hopping strength . In combination with the method of the effective potential, this technique permits us to determine characteristic quantities with an accuracy far greater than that of mean-field methods.
In this talk I will concentrate on the calculation of the superfluid and of the condensate density for the Bose-Hubbard model, and demonstrate how the process-chain approach can be employed for obtaining the critical exponents characterizing the system near the superfluid-to-Mott insulator quantum phase transition.
 N. Teichmann, D. Hinrichs, M. Holthaus, and A. Eckardt, PRB 79, 224515 (2009).