Münster 2011 – wissenschaftliches Programm
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HK: Fachverband Physik der Hadronen und Kerne
HK 2: Schwerionenkollisionen und QCD Phasen I
HK 2.1: Gruppenbericht
Montag, 21. März 2011, 14:00–14:30, HS AP
Influence of a finite volume on the QCD phase diagram — •Bertram Klein1, Jens Braun2, and Bernd-Jochen Schaefer3 — 1Technische Universität München — 2Universität Jena — 3Universität Graz
A very important method for studying QCD at finite temperature and density is the simulation on a discrete and finite space-time lattice. Both the discretization and the finite volume lead to errors in the results which need to be assessed carefully for extrapolations to the continuum theory in infinite volume.
With regard to the physics of phase transitions and critical phenomena, long-range fluctuations are of great importance, and a finite volume will affect these fluctuations. For small pion masses, such effects will be increasingly manifest in the finite-volume results. They may also affect the shape of the phase transition line at finite temperature and density.
We use a quark-meson model for the breaking of chiral symmetry to investigate effects of a finite volume on the phase diagram of QCD in the case of two quark flavors. We include the effects of long-range fluctuations by means of a non-perturbative renormalization group method. In particular, we discuss the curvature of the chiral phase transition line at finite temperature and density and how it is affected by a finite volume, depending on the spatial boundary conditions for the quark fields. We discuss implications for the QCD phase diagram.