Testing Lorentz and CPT invariance with ultracold neutrons

摘要

In this paper we investigate, within the standard model extension framework, the influence of Lorentzand CPT-violating terms on gravitational quantum states of ultracold neutrons. Using a semiclassical wave packet, we derive the effective nonrelativistic Hamiltonian which describes the neutrons vertical motion by averaging the contributions from the perpendicular coordinates to the free falling axis. We compute the physical implications of the Lorentz- and CPT-violating terms on the spectra. The comparison of our results with those obtained in the GRANIT experiment leads to an upper bound for the symmetriesviolation c_(μν)~n coefficients. We find that ultracold neutrons are sensitive to the a_i~n and e_i~n coefficients, which thus far are unbounded by experiments in the neutron sector. We propose two additional problems involving ultracold neutrons which could be relevant for improving our current bounds; namely, gravityresonance spectroscopy and neutron whispering gallery wave.