Abstract:
The QCD phase transition is studied on $16^3$ and $32^3
\times 4$ lattices both with and without quark loops. We
introduce a new zero-flavor or quenched species of quark
$\zeta$ and study the resulting chiral condensate, $\azbz$
as a function of the $\zeta$ mass, $m_\zeta$. By examining
$\azbz$ for $10^{-10} \le m_\zeta \le 10$ we gain
considerable information about the spectrum of Dirac
eigenvalues. A comparison of $ma=0.01$ and 0.025 shows
little dependence of the Dirac spectrum on such a light,
dynamical quark mass, after an overall shift in $\beta$ is
removed. The presence of sufficient small eigenvalues to
support anomalous chiral symmetry breaking in the high
temperature phase is examined quantitatively. In an effort
to enhance these small eigenvalues, $\azbz$ is also examined
in the pure gauge theory in the region of the deconfinement
transition with unexpected results. Above the critical
temperature, the three $Z_3$ phases show dramatically
different chiral behavior. Surprisingly, the real phase
shows chiral symmetry, suggesting that a system with one
flavor of staggered fermion at $N_t=4$ will possess a chiral
a phase transition---behavior not expected in the continuum
limit.
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