Precision Measurement of the Position-Space Wave Functions of Gravitationally Bound Ultracold Neutrons

Y Kamiya,G Ichikawa,S Komamiya

doi:10.1155/2014/859241

Y Kamiya, G Ichikawa + Show 1 more

Open Access

https://doi.org/10.1155/2014/859241

Copy DOI

Abstract

Gravity is the most familiar force at our natural length scale. However, it is still exotic from the view point of particle physics. The first experimental study of quantum effects under gravity was performed using a cold neutron beam in 1975. Following this, an investigation of gravitationally bound quantum states using ultracold neutrons was started in 2002. This quantum bound system is now well understood, and one can use it as a tunable tool to probe gravity. In this paper, we review a recent measurement of position-space wave functions of such gravitationally bound states and discuss issues related to this analysis, such as neutron loss models in a thin neutron guide, the formulation of phase space quantum mechanics, and UCN position sensitive detectors. The quantum modulation of neutron bound states measured in this experiment shows good agreement with the prediction from quantum mechanics.

Highlights

Phenomena due to the gravitational field have been well understood at the macroscopic scales
Even though quantum mechanics was established in the early 1900s, the first experiment to investigate a quantum effect under gravity was reported in 1975 by the group of Colella [1], where a neutron interference pattern induced by a gravitational potential was observed
Experiments exploiting other ideas for measuring the energy scale, that is, the energy differences between quantum states, are proposed by observing resonance transitions induced by a magnetic field [16,17,18,19] and mechanical vibrations [20]

Summary

Introduction

Phenomena due to the gravitational field have been well understood at the macroscopic scales. Experiments exploiting other ideas for measuring the energy scale, that is, the energy differences between quantum states, are proposed by observing resonance transitions induced by a magnetic field [16,17,18,19] and mechanical vibrations [20]. These projects are called GRANIT [21] and qBounce, respectively. A new limit for the CP-violating Yukawa-type potential using the resonance method was reported in [23] It shows a limit for the chameleon field [24,25,26], a dark energy candidate

Precision Measurement and Issues Related to This Analysis

Bottom mirror

Summary