Abstract
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 cluster model for . 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 cluster model, we find that the effects of rotational symmetry breaking can be largely eliminated for lattice spacings of , and we expect similar improvement for lattice Monte Carlo calculations.
- Received 22 April 2015
DOI:https://doi.org/10.1103/PhysRevD.92.014506
© 2015 American Physical Society