46 research outputs found
Effective model for pure Yang-Mills theory on with Polyakov loops
We investigate the phase diagram and thermodynamics of pure
Yang-Mills theory on a manifold with an
effective model that includes two Polyakov loops along two compactified
directions. We find that a rich phase structure can appear owing to the
spontaneous breaking of two center symmetries for and . Thermodynamic
quantities are obtained in the model and compared with recent lattice results.
It is shown that two Polyakov loops play significant roles in thermodynamics on
.Comment: 14 pages, 10 figure
Fate of the topological susceptibility in two-color dense QCD
We explore the topological susceptibility at finite quark chemical potential
and zero temperature in two-color QCD (QCD) with two flavors. Through the
Ward-Takahashi identities of QCD, we find that the topological
susceptibility in the vacuum solely depends on three observables: the pion
decay constant, the pion mass, and the mass in the low-energy regime of
QCD. Based on the identities, we numerically evaluate the topological
susceptibility at finite quark chemical potential using the linear sigma model
with the approximate Pauli-Gursey symmetry. Our findings indicate that,
in the absence of anomaly effects represented by the
Kobayashi-Maskawa-'t Hooft-type determinant interaction, the topological
susceptibility vanishes in both the hadronic and baryon superfluid phases. On
the other hand, when the anomaly effects are present, the constant and
nonzero topological susceptibility is induced in the hadronic phase, reflecting
the mass difference between the pion and meson. Meanwhile, in the
superfluid phase it begins to decrease smoothly. The asymptotic behavior of the
decrement is fitted by the continuous reduction of the chiral condensate in
dense QCD, which is similar to the behavior observed in hot three-color QCD
matter. In addition, effects from the finite diquark source on the topological
susceptibility are discussed. We expect that the present study provides a clue
to shed light on the role of the anomaly in cold and dense QCD matter.Comment: 36 pages, 8 figure