Performing the two slit experiment under a strong gravitational force For elementary particles, are their associated De Broglie wavelengths affected by the spacetime curvature produced by large mass density values?
I ask this as a newcomer to Q.M. so apologies if I have not thought it through completely or if  I have misunderstood a basic concept.
I would guess the answer is yes, but if that is the case, then should we be able to reconcile  results from two separate  two slit experiments, one near a strong gravity source and the other occurring  in flat space? 
 A: Given how weak gravity is compared to the other fundamental forces, in practical cases where we do quantum mechanics (subatomic, atomic, molecular physics, solid state, etc.) gravity is utterly negligible.  Once we try to work in a regime (such as near a micro-black hole) where gravitational forces are comparable with other forces you are into the regime of quantum gravity.  We don't yet have a working theory of quantum gravity, so there is probably no simple answer known to your question.
A: The double slit experiment has been performed under varying gravity conditions. Granted, this was Earth gravity, which wouldn't be considered strong by any means, but the effects were measurable. These were first written about in 1974-75:


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*A.W. Overhauser and R. Colella, “Experimental test of gravitationally induced quantum interference,”  Phys. Rev. Lett.  33 (1974), 1237

*R. Colella, A.W. Overhauser and S.A. Werner, “Observation of gravitationally induced quantum interference,” Phys. Rev. Lett. 34 (1975), 1472.


This experiment used neutrons in a double slit experiment where the two paths were vertically displaced, leading to different phase shifts in the two wavefunction due to the varying gravitational potential.
A good explanation can be found here: http://skullsinthestars.com/2015/05/20/1975-the-year-that-quantum-mechanics-met-gravity/
A: An astrophysical maser, microlensed by a foreground object (star or extrasolar planet) passing by, could maybe do the trick.
The wave pattern will be much larger than earth so it will have to be measured over time as earth passes through it.
The biggest difficulty will be finding a suitable candidate.
