A novel wideband neutron-earth resonant quantum detector for gravitational waves.

The detectors of astrophysical gravitational waves are based on optical interferometers. There is not yet an analogue of a quantum mechanical atomic detector of photons for the detection of gravitational waves. I point out the remarkable fact that the already observed pico-electron volt quantization of energy levels of ultra-cold neutrons, gravitationally bound to the Earth in a bouncing mode, fortuitously coincide with the range of energies of the hypothetical quanta of astrophysical gravitational waves. Thus, it is feasible to use a cold-neutron bouncing reservoir as a novel quantum sensor for directly detecting astrophysical gravitational waves, in a wide frequency band. These considerations also lead us to the discovery that many detected signals in interferometric detectors like LIGO correspond to the energy of a single gravitational quantum or less. This surprising finding enables a decisive experimental test of quantum gravity. [ABSTRACT FROM AUTHOR]