0 20 80 24 v 3 1 8 Se p 20 02 Conceptual tensions between quantum mechanics and general relativity : Are there experimental consequences , e . g . , superconducting transducers between electromagnetic and gravitational radiation ?

One of the conceptual tensions between quantum mechanics (QM) and general relativity (GR) arises from the clash between the spatial nonseparability of entangled states in QM, and the complete spatial separability of all physical systems in GR, i.e., between the nonlocality implied by the superposition principle, and the locality implied by the equivalence principle. Experimental consequences of this conceptual tension will be explored for macroscopically coherent quantum fluids, such as superconductors, superfluids, and atomic Bose-Einstein condensates (BECs), subjected to tidal and Lense-Thirring fields arising from gravitational radiation. A Meissner-like effect is predicted, in which the Lense-Thirring field is expelled from the bulk of a quantum fluid, apart from a thin layer given by the London penetration depth λL. For atomic BECs, λL is a microscopic length given by (8πna) where n is the mean atomic density of the BEC, and a is the scattering length of S-wave scattering, which produces quantum entanglement of pairs of atoms with opposite momenta. Superconductors are predicted to be macroscopic quantum gravitational antennas and transducers, which can directly convert upon reflection a beam of quadrupolar electromagnetic radiation into gravitational radiation, and vice versa, and thus serve as both sources and receivers of gravitational waves. An estimate of the transducer conversion efficiency on the order of unity comes out of the Ginzburg-Landau theory for an extreme type II, dissipationless superconductor with minimal coupling to weak gravitational and electromagnetic radiation fields,