On the possibility of detecting gravity of an object frozen in a spatial superposition by the Zeno effect

Abstract

While quantum probes surely feel gravity, no source of gravity has been prepared in a delocalised quantum state yet. Two basic questions need to be addressed: how to delocalise a mass sufficiently large to generate detectable gravity; and, once that state has been prepared, how to fight localisation by decoherence. We propose to fight decoherence by freezing the source in the desired state through the Zeno effect. Successful implementation can be verified by scattering a probe in the effective potential generated by the source. Besides putting forward the idea, we provide a first estimation of the values of the parameters required for the proposal to be feasible. Overall, the proposal seems as challenging as other existing ones, although the specific challenges are different (e.g. no entanglement needs to be preserved or detected, but the Zeno freezing must be implemented).