Breaking and restoration of rotational symmetry for irreducible tensor operators on the lattice

作     者：Bing-Nan Lu Timo A. Lähde Dean Lee Ulf-G. Meißner 

作者机构：Institute for Advanced Simulation Institut für Kernphysik and Jülich Center for Hadron Physics Forschungszentrum Jülich D-52425 Jülich Germany Department of Physics North Carolina State University Raleigh North Carolina 27695 USA Helmholtz-Institut für Strahlen- und Kernphysik and Bethe Center for Theoretical Physics Universität Bonn D-53115 Bonn Germany JARA-High Performance Computing Forschungszentrum Jülich D-52425 Jülich Germany 

出 版 物：《Physical Review D》 (Phys Rev D Part Fields Gravit Cosmol)

年 卷 期：2015年第92卷第1期

页      面：014506-014506页

核心收录：

学科分类：07[理学] 0827[工学-核科学与技术] 0704[理学-天文学] 0702[理学-物理学] 

基　　金：Deutsche Forschungsgemeinschaft (Sino-German) [CRC 110] Helmoholtz Association [VH-VI-417] BMBF [05P12PDTEE] U.S. Department of Energy [DE-FG02-03ER41260] EU HadronPhysics3 project Magnus Ehrnrooth Foundation of the Finnish Society of Sciences and Letters 

摘      要：We study the breaking of rotational symmetry on the lattice for irreducible tensor operators and practical methods for suppressing such breaking. We illustrate the features of the general problem using an α cluster model for Be8. We focus on the lowest states with nonzero angular momentum and examine the matrix elements of multipole moment operators. We show that reduced matrix elements are well reproduced by averaging over all possible orientations of the quantum state. This averaging is performed in terms of a sum of matrix elements weighted by the Clebsch-Gordan coefficients of each orientation. For our α cluster model, we find that the effects of rotational symmetry breaking can be largely eliminated for lattice spacings of a≤1.7 fm, and we expect similar improvement for lattice Monte Carlo calculations.