Speaker
Oliver Orasch
(University of Graz)
Description
We study a complex $\phi^4$ field at finite temperature and finite density using a worldline representation. In particular we focus on the low temperature regime where the particle number shows condensation steps as a function of the chemical potential. The critical values of the chemical potential, i.e., the condensation thresholds, are related to the mass and higher multi-particle energies and can be determined within a simulation. We study the first three condensation thresholds, i.e, $\mu^{(i)}_c, \, i = 1,2,3$, which are linked to the 2- and 3-particle energies as a function of the spatial volume $L^{d-1}$. The L-dependence of the multi-particle energies is described by Lüscher's formula in the 2-particle sector and by its generalization in the 3-particle case. These finite size scaling functions carry the scattering information. Finally, we cross-check the results with conventional simulations at vanishing chemical potential where we extract the mass and the 2- and 3-particle energies from the 2-, 4- and 6-point correlation functions.
Primary authors
Prof.
Christof Gattringer
(University of Graz)
Mario Giuliani
(University of Graz)
Oliver Orasch
(University of Graz)