出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：In the rst part of this contribution we present a numerical study motivated by recent attempts to
understand the nonperturbative aspects of QCD at temperatures T a few times the deconnement
temperature Tc. We focus on the pure gauge theory, and ask whether the decit in pressure
and entropy, with respect to their free-gas values, is particular to SU(3). We nd that the decit
in SU(4);SU(8) for T 2Tc;1:6Tc, respectively, is remarkably close to that of SU(3). This suggests
a similar decit for SU(¥), which is fortunate since this theory is simpler, and can serve to
constrain the possible dynamics underlying the decits.
In the second part we seek for signs of a Hagedorn temperature TH in pure lattice SU(N) gauge
theories with N = 8;10; 12. Since one expects TH > Tc, we measure masses of strings in the
metastable conned phase above Tc, and extrapolate them to zero to estimate TH. For SU(12) we
nd that TH=Tc =1:116(9), when we extrapolate with a critical exponent of the three dimensional
XY model, which seems to be preferred over a mean eld exponent by our data.
