670 research outputs found
Characteristics of the eigenvalue distribution of the Dirac operator in dense two-color QCD
We exposit the eigenvalue distribution of the lattice Dirac operator in
Quantum Chromodynamics with two colors (i.e. two-color QCD). We explicitly
calculate all the eigenvalues in the presence of finite quark chemical
potential \mu for a given gauge configuration on the finite-volume lattice.
First, we elaborate the Banks-Casher relations in the complex plane extended
for the diquark condensate as well as the chiral condensate to relate the
eigenvalue spectral density to the physical observable. Next, we evaluate the
condensates and clarify the characteristic spectral change corresponding to the
phase transition. Assuming the strong coupling limit, we exhibit the numerical
results for a random gauge configuration in two-color QCD implemented by the
staggered fermion formalism and confirm that our results agree well with the
known estimate quantitatively. We then exploit our method in the case of the
Wilson fermion formalism with two flavors. Also we elucidate the possibility of
the Aoki (parity-flavor broken) phase and conclude from the point of view of
the spectral density that the artificial pion condensation is not induced by
the density effect in strong-coupling two-color QCD.Comment: 19 pages, 9 figures, reference added, some more clarificatio
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