Chirped-Frequency Excitation of Gravitationally Bound Ultracold Neutrons

TL;DR

This paper proposes a chirped-frequency excitation method for ultracold neutrons in Earth's gravity, enabling controlled energy level transitions and potential tests of gravity at short distances.

Contribution

It introduces a novel chirped-frequency technique to excite gravitational quantum states of neutrons, facilitating quantum state control and gravity tests.

Findings

Neutrons can be driven to higher energy states using chirped excitation.

The method allows observation of quantum-classical transition at high energies.

Potential to create superpositions of gravitational quantum states.

Abstract

Ultracold neutrons confined in the Earth's gravitational field display quantized energy levels that have been observed for over a decade. In recent resonance spectroscopy experiments [T. Jenke et al., Nature Phys. 7, 468 (2011)], the transition between two such gravitational quantum states was driven by the mechanical oscillation of the plates that confine the neutrons. Here we show that, by applying a sinusoidal modulation with slowly varying frequency (chirp), the neutrons can be brought to higher excited states by climbing the energy levels one by one. The proposed experiment should make it possible to observe the quantum-classical transition that occurs at high neutron energies. Furthermore, it provides a technique to realize superpositions of gravitational quantum states, to be used for precision tests of gravity at short distances.