A neutron whispering gallery state is a quantum state localized on a material surface bound by the centrifugal force and the material potential. Precise measurements of such quantum states enable tests of quantum mechanics in non-inertial frames, characterization of the surface potential, and searches for hypothetical short-range interactions at the nanometer scale. We observed a neutron whispering gallery state on a $\mathrm{ SiO}_2$ concave mirror using a pulsed cold neutron beam. The measured results agree with theoretical calculations within $1.9\%$ for the centrifugal acceleration $a \approx 7\times 10^7\,\mathrm{ m/s^2}$, which is due to unmodeled deviations of the shape of the concave mirror edge from an ideal one. We found that the sensitivity itself was $1\times 10^{ -4}$, which is two orders of magnitude better than the above agreement.
Categories: hep-ex physics.ins-det quant-ph