The dynamics of a quantum wave packet of a neutron bouncing under the influence of gravity - Newton's law and the question of extra dimensions of space-time

• Applicant: Professor Dr. Hartmut Abele
• Subject Area: Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields
• Term: from 2008 to 2011
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 66291586

The dynamics of a quantum mechanical wave packet bouncing off a hard surface in the gravitational field of the earth combines quantum theory with aspects of Newtonian mechanics at short distances. We propose to realize such a quantum bouncing ball with ultracold neutrons in a system, in which we have measured before the lowest stationary quantum states in the earth’s gravitational field. For the new purpose, a careful measurement of the neutron density distribution above the mirror is necessary, and spatial neutron detectors must be developed. This experiment is sensitive to gravity-like forces at a length scale below 10 μm, where we already place limits. The limits can be significantly improved by studying the dynamics of the wave packets, because Newtonian gravity and hypothetical fifth forces evolve with different phase information. Such forces can be mediated from gauge bosons propagating in a higher dimensional space and this experiment can therefore test speculations on large extra dimensions of submillimeter size of space-time or the origin of the cosmological constant in the universe, where effects are predicted in the interesting range of this experiment and might give a signal in an improved setup.

• DFG Programme: Research Grants
• International Connection: Austria