Rational hybrid Monte Carlo algorithm for theories with unknown spectral bounds
- Department of Energy, Division of High Energy Physics, Washington, D.C. 20585 (United States) and Dept. of Physics-TQHN, Univ. of Maryland, 82 Regents Dr., College Park, Maryland 20742 (United States)
The Rational Hybrid Monte Carlo (RHMC) algorithm extends the Hybrid Monte Carlo algorithm for lattice QCD simulations to situations involving fractional powers of the determinant of the quadratic Dirac operator. This avoids the updating increment (dt) dependence of observables which plagues the Hybrid Molecular-dynamics (HMD) method. The RHMC algorithm uses rational approximations to fractional powers of the quadratic Dirac operator. Such approximations are only available when positive upper and lower bounds to the operator's spectrum are known. We apply the RHMC algorithm to simulations of 2 theories for which a positive lower spectral bound is unknown: lattice QCD with staggered quarks at finite isospin chemical potential and lattice QCD with massless staggered quarks and chiral 4-fermion interactions ({chi}QCD). A choice of lower bound is made in each case, and the properties of the RHMC simulations these define are studied. Justification of our choices of lower bounds is made by comparing measurements with those from HMD simulations, and by comparing different choices of lower bounds.
- OSTI ID:
- 20868115
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 74, Issue 11; Other Information: DOI: 10.1103/PhysRevD.74.114505; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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