Monday, April 18, 2011

Neutron Gravitational Quantum States Probed

Several years ago (in fact, close to 10 years ago), we read about an amazing experiment that showed for the first time the gravitational quantum states done by using a neutron free fall experiment. Now long comes an experiment, almost 10 years later, that probed these quantum states, again using neutrons, but with an induced frequency in one of the plate[1].

The new work by the ILL team has added what is known as a piezoelectric resonator to the bottom plate; its purpose is to jiggle the bottom plate at a very particular frequency.

The researchers found that as they changed the bottom plate's vibration frequency, there were distinct dips in the number of neutrons detected outside the plates - particular, well-spaced "resonant" frequencies that the neutrons were inclined to absorb.

These frequencies, then, are the gravitational quantum states of neutrons, essentially having energy bounced into them by the bottom plate, and the researchers were able for the first time to force the neutrons from one quantum state to another.

This then could be used as an extremely sensitive device to measure gravity at atomic scale.

Fascinating experiment.


[1] T. Jenke et al. Nature Physics doi:10.1038/nphys1970 (online publication - full citation not available yet).

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