Greetings. I seem to be the only one out there with non-EM based matter/spacetime interaction mechanisms. Yes, the manipulations are EM based but the actual coupling rationales are not. At the risk of provoking Brutes, I mean Bruce's ire, I will present them below.
1) Maximum violation of weak nuclear force parity conservation may be viewed in a Standard Model light as disappearance of weak force "charge" into the vacuum upon a reversal of massive particle spin handedness, (see Howard Georgi's "A Unified Theory of Elementary Particles and Forces," Sci. Am., 1981). This acceptance or return of weak nuclear force charge by the vacuum based on massive particle chirality may be interpreted as a sort of matter/spacetime interaction mechanism and nuclear spin manipulations are easily accomplished in a laboratory setting using nuclear magnetic resonance techniques.
2) A second quantum level effect having potential for matter/spacetime interaction may be visualized in Flatland. A Flatland resident cannot manipulate a two dimensional chiral outline in any way which can produce its enantiomorph. However, a three dimensional Solidlander can easily turn over a two dimensional outline in his third spatial dimension to produce the enantiomorph. The Flatlander watching this extradimensional inversion, since he cannot look "up," will see only a quantum transition with no intermediate state of orientation.
A three dimensional chiral particle, such as a left hand spin proton, may be similarly inverted in a fourth spatial dimension if such exists in Nature. This will produce its enantiomorph, a right hand spin proton. This extradimensional inversion will now appear to a Solidlander as a quantum transition. For us, massive particle spin inversions in a postulated fourth spatial dimension are identical in appearance to quantum spin flips. This represents a sort of matter/spacetime interaction mechanism and quantum spin manipulations are easily accomplished in a laboratory setting using nuclear magnetic resonance techniques.
3) Phase entanglement has been shown by the Clauser/Freedman and Alain Aspect experiments testing Bell's Theorem to strongly and non-locally correlate polarization angles between photons created in a common quantum event. This connection has been described by Herbert, ( "Quantum Reality: Beyond the New Physics," An Anchor Book, Doubleday, NY), as "unmitigated" (by distance), "unmediated" (by any known particle or force), and "immediate" (simultaneous anywhere in the universe). It is here assumed that phase entanglement may be assigned as a testable property of spacetime.
Massive particles created in a common quantum event are also non-locally, though perhaps not strongly correlated in their spin orientations, the massive particle analog to wave polarization angles. For example, beta negative reactions may enrich a working fluid in phase entangled proton/electron partners. Such a working fluid might be produced by neutron bombardment of say, a magnesium isotope, Mg26, to eventually give Al27.
Electrons formed in these beta negative events and eventually bound in atomic orbitals may then be spin aligned in a stationary magnetic field - and electron cloud alignments then influence nuclear alignment to "spin up" or "spin down" states. The phase entanglement enriched and spin aligned working fluid may next have a magnetic resonance tuned radio frequency field applied to nuclei while electron partners continue to be held spin invariant on at least one axis by the stationary magnetic field. When the resulting "irresistable" proton spin flips meet their "immovable" electron spin partners, the assigned spacetime phase entanglement property between them may "twist" to distort spacetime in the working fluid. This enforced geometric distortion of an assigned spacetime property represents a sort of matter/spacetime interaction mechanism and the quantum spin flips are easily accomplished in a laboratory setting using these nuclear magnetic resonance techniques.
4) By combining very high velocities with very dense spinning matter, a theoretical matter/spacetime interaction machine, known as a "Tipler" machine is possible to exist. Usually associated with a spinning neutron star, sub-relativistic velocities and matter density less than that of a black hole can combine to produce relativistic effects. Of course an atomic nucleus exists at neutron star density, but with such a small concentration of mass it would still require relativistic velocity to produce relativistic effects in the local region surrounding the nucleus. But in the quantum world all quantum transitions take no time at all. Matter is either in one state or in another state with no Mr. In-Between. Once again, quantum spin flips achieved at infinite velocity may be interpreted as a sort of "Tipler" matter/spacetime interaction mechanism and nuclear spin manipulations are easily accomplished in a laboratory setting using nuclear magnetic resonance techniques.
So here I have presented four quantum level rationales or interpretations of known quantum phenomena which may be considered to be potential matter/spacetime interaction mechanisms - and I could probably cook up a fifth using frame dragging. There is more to the experimental regiment than I have discussed here, but basically the hardware and techniques are off-the-shelf and should not be expensive, the rationales for the experiment exist and seem to violate no physical laws, and there is a clear experimental outcome - matter/spacetime interaction distorting spacetime should induce interaction with the solar and stellar neutrino fluxes through Uncertainty Relation influnce and apparent blueshifting of neutrino kinetic energies as discussed in my earlier post on BH Forum II on weak force reactions and E conservation. ( I know Bruce - its not in GR, but then neither is toilet paper). Whether or not you buy into the energy conservation end, here is matter/spacetime interaction - maybe. Only running an experiment will tell for sure.
Most of this material appeared in my poster paper for NASA's BPP Workshop and was subsequently published in the proceedings. It has also appeared in greater detail on Yahoo's "greenglow" forum and on NIDS forum, archive #6.
Reflect and enjoy!