The chiral phase transition of QCD with 2+1 flavors [Elektronische Ressource] : a lattice study on Goldstone modes and universal scaling / vorgelegt von Wolfgang Unger

The Chiral Phase Transition of QCD with 2+1 FlavorsA lattice study onGoldstone modes and universal scalingDissertationzur Erlangung des Doktorgradesan der Fakultat fur Physik¨ ¨der Universitat Bielefeld¨vorgelegt vonWolfgang UngerAugust 2010◦◦Gedruckt auf alterungsbestandigem Papier ISO 9706¨AbstractThisPhDthesisisconcernedwiththechiralphasetransitionofQCDwithtwodegeneratelightquarkmasses and a strange quark mass close to its physical value. We analyze the quark mass dependenceof the chiral condensate and chiral susceptibilities close to the transition temperature. The analysisis twofold:FirstweprovideevidencefortheinfluenceofthermalfluctuationsofGoldstonemodesonthechiralcondensate at finite temperature. We show that at temperatures below but close to the chiral phasetransition at vanishing quark mass this leads to a characteristic dependence of the light quark chiralcondensate on the square root of the light quark massm. As a consequence the chiral susceptibilityl−1/2shows a strong quark mass dependence for all temperatures belowT and diverges likem in thec lchiral limit. We separately examine the divergence of disconnected and connected parts of the lightquarksusceptibilityanddiscussthevolumeaswellascut-offdependenceofsusceptibilitiesandchiralcondensates.Second we analyze the critical behavior of the chiral transition with a scaling analysis basedon the O(N) scaling functions.