Must the gravitational field obey quantum superposition?
In plain words
If a mass is in two places at once, is its gravitational field also in two configurations at once, or is gravity a classical field that only responds to the average? Experiments at low energy can in principle decide.
Precise statement
Determine whether the low-energy gravitational field of laboratory masses can exist in superpositions of distinct configurations and carry quantum information, or is a classical field coupled to quantum matter (mean-field semiclassical, stochastic classical-quantum, or collapse-based). An answer is an experimental result that excludes one class under stated assumptions, such as locality of the mediator.
What would settle it
A gravitationally mediated entanglement experiment or a decoherence-diffusion measurement that excludes the classical-field model classes.
Related problems
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- More general than Measure the gravity of a mass that is in superposition