出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：The overlap Dirac operator at nonzero quark chemical potential involves the computation of the
sign function of a non-Hermitian matrix. In this talk we present iterative Krylov subspace approximations,
with deflation of critical eigenvalues, which we developed to compute the operator on
large lattices. We compare the accuracy and efficiency of two alternative approximations based
on the Arnoldi and on the two-sided Lanczos method. The short recurrences used in the latter
method make it faster and more effective for realistic lattice simulations.
