Nuclear Matrix Elements for Tests of Fundamental Symmetries

The nuclear matrix elements for the momentum quadrupole operator are important for the interpretation of precision atomic physics experiments that search for violations of Lorentz symmetry. We use the configuration-interaction nuclear shell model and self-consistent mean field theory to calculate these matrix elements in ²¹Ne. These are the first microscopic calculations for the momentum quadrupole tensor that go beyond the single-particle estimate. We show that the momentum matrix elements are strongly suppressed by the many-body correlations, in contrast to the well known enhancement of the spatial quadrupole nuclear matrix elements.