科研之友
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摘要
We study a strongly coupled Z(2) lattice gauge theory with two flavors of quarks, invariant under an exact SU(2) x SU(2) x U-A(1) x U-B(1) symmetry which is the same as in QCD with two flavors of quarks without an anomaly. The model also contains a coupling that can be used to break the UA(1) symmetry and thus mimic the QCD anomaly. At low temperatures T and small baryon chemical potential mu(B) the model contains massless pions and massive bosonic baryons similar to QCD with an even number of colors. In this work we study the T - mu(B) phase diagram of the model and show that it contains three phases: (1) A chirally broken phase at low T and mu(B), (2) a chirally symmetric baryon superfluid phase at low T and high mu(B), and (3) a symmetric phase at high T. We find that the nature of the finite temperature chiral phase transition and in particular the location of the tricritical point that seperates the first order line from the second order line is affected significantly by the anomaly.
- 出版日期2010-12
