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HK: Physik der Hadronen und Kerne
HK 5: Theorie
HK 5.4: Talk
Monday, March 20, 2006, 14:45–15:00, B
Volume dependence of the chiral phase transition — •Bertram Klein1, Jens Braun2, Hans-Jürgen Pirner2, and Amir H. Rezaeian2 — 1GSI, Planckstrasse 1, 64159 Darmstadt — 2Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 19, 69120 Heidelberg
We investigate chiral symmetry restoration at finite temperature in a finite volume for the quark-meson model, using renormalization group methods. We determine the dependence of the transition temperature on the size of the spatial volume and on the value of the current-quark mass.
We find that the transition temperature is only weakly volume-dependent for large current-quark masses, but depends strongly on the volume for small current-quark masses and correspondingly for small pion masses. We also find a clear dependence on the choice of the quark boundary conditions for the spatial directions. We conclude from our model results that finite-volume effects should remain small for volume sizes of the order of 2 fm, if pion masses are about 300 MeV, but that they can become significantly larger if the pion mass is decreased to more realistic values.