出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：In this lecture we discuss various properties of the phase factor of the fermion determinant for
QCD at nonzero chemical potential. Its effect on physical observables is elucidated by comparing
the phase diagram of QCD and phase quenched QCD and by illustrating the failure of the
Banks-Casher formula with the example of one-dimensional QCD. The average phase factor and
the distribution of the phase are calculated to one-loop order in chiral perturbation theory. In
quantitative agreement with lattice QCD results, we nd that the distribution is Gaussian with a
width mTpV (for mp T LQCD). Finally, we introduce, so-called teon plated observables
which can be calculated accurately by Monte Carlo even though the sign problem is severe.
