QUANTUM MECHANICS AT THE MACROSCOPIC LEVEL

William W. Kennerly

A. J. Leggett

Alastair Wilson

Simon Saunders and David Wallace have proposed an attractive semantics for interpreting linguistic communities embedded in an Everettian multiverse. It provides a charitable interpretation of our ordinary talk about the future, and allows us to retain a principle of bivalence for propositions and to retain the law of excluded middle in the logic of propositions about the future. But difficulties arise when it comes to providing an appropriate account of the metaphysics of macroscopic objects and events. I evaluate various metaphysical frameworks which might be combined with the Saunders–Wallace semantics. I conclude that the most appropriate metaphysics to underwrite the semantics renders Everettian quantum mechanics a theory of non‐overlapping worlds.

C. GEORGE, Ilya Prigogine, L. Rosenfeld

Yang Ran, Xuefei Gong, Shouyong Pei +2 more

Single-photon Michelson interferometry as a probe to macroscopic quantum mechanics is considered. With dual output readout at both the bright and dark ports, it is shown that a nonlocal, linear superposition of two Schrödinger cats may be generated by the opto-mechanical coupling of a single photon with a movable macroscopic quantum mirror in one arm of the interferometer. With a balanced homodyne readout scheme, a CHSH inequality may be formulated and the violation of which serves to verify the nonlocality of the two spacelike separated Schrödinger cats. The relevance of this result in our understanding of possible wave function collapse dynamics is briefly touched upon. Macroscopic entangled state of two mirrors generated by opto-mechanical coupling and the associated CHSH inequality are also discussed.

Sudip Chakravarty