Bloch, Jacques C. R. and Breu, Tobias and Frommer, Andreas and Heybrock, Simon and Schaefer, Katrin and Wettig, Tilo (2010) Short-recurrence Krylov subspace methods for the overlap Dirac operator at nonzero chemical potential. COMPUTER PHYSICS COMMUNICATIONS, 181 (8). pp. 1378-1387. ISSN 0010-4655, 1879-2944
Full text not available from this repository. (Request a copy)Abstract
The overlap operator in lattice QCD requires the computation of the sign function of a matrix, which is non-Hermitian in the presence of a quark chemical potential. In previous work we introduced an Arnoldi-based Krylov subspace approximation, which uses long recurrences. Even after the deflation of critical eigenvalues, the low efficiency of the method restricts its application to small lattices. Here we propose new short-recurrence methods which strongly enhance the efficiency of the computational method. Using rational approximations to the sign function we introduce two variants, based on the restarted Arnoldi process and on the two-sided Lanczos method, respectively, which become very efficient when combined with multishift solvers. Alternatively, in the variant based on the two-sided Lanczos method the sign function can be evaluated directly. We present numerical results which compare the efficiencies of a restarted Arnoldi-based method and the direct two-sided Lanczos approximation for various lattice sizes. We also show that our new methods gain substantially when combined with deflation. (C) 2010 Elsevier B.V. All rights reserved.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | CHIRAL-SYMMETRY; SIGN-FUNCTION; MATRIX; LATTICE; Overlap Dirac operator; Quark chemical potential; Sign function; Non-Hermitian matrix; Iterative methods |
| Subjects: | 500 Science > 530 Physics |
| Divisions: | Physics > Institute of Theroretical Physics > Chair Professor Braun > Group Tilo Wettig |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 20 Jul 2020 08:23 |
| Last Modified: | 20 Jul 2020 08:23 |
| URI: | https://pred.uni-regensburg.de/id/eprint/24369 |
Actions (login required)
 |
View Item |
