Space, time, and the macroworld

D. I. Blokhint︠s︡ev

Walter T. Strunz, Fritz Haake, Daniel Braun

We consider environment induced decoherence of quantum superpositions to mixtures in the limit in which that process is much faster than any competing one generated by the Hamiltonian $H_{\rm sys}$ of the isolated system. This interaction dominated decoherence limit has previously not found much attention even though it is of importance for the emergence of classical behavior in the macroworld, since it will always be the relevant regime for large enough separations between superposed wave packets. The usual golden-rule treatment then does not apply but we can employ a short-time expansion for the free motion while keeping the interaction $H_{\rm int}$ in full. We thus reveal decoherence as a universal short-time phenomenon largely independent of the character of the system as well as the bath. Simple analytical expressions for the decoherence time scales are obtained in the limit in which decoherence is even faster than any timescale emerging from the reservoir Hamiltonian $H_{\rm res}$.

Detlef Dürr, Stefan Teufel

Walter T. Strunz, Fritz Haake, Daniel Braun

We consider environment induced decoherence of quantum superpositions to mixtures in the limit in which that process is much faster than any competing one generated by the Hamiltonian $H_{\rm sys}$ of the isolated system. This interaction dominated decoherence limit has previously not found much attention even though it is of importance for the emergence of classical behavior in the macroworld, since it will always be the relevant regime for large enough separations between superposed wave packets. The usual golden-rule treatment then does not apply but we can employ a short-time expansion for the free motion while keeping the interaction $H_{\rm int}$ in full. We thus reveal decoherence as a universal short-time phenomenon largely independent of the character of the system as well as the bath. Simple analytical expressions for the decoherence time scales are obtained in the limit in which decoherence is even faster than any timescale emerging from the reservoir Hamiltonian $H_{\rm res}$.

Ulrich Mohrhoff

Recently Shafiee, Jafar-Aghdami, and Golshani (Studies in History and Philosophy of Modern Physics, 37, 316--329) took issue with certain aspects of the Pondicherry interpretation of quantum mechanics, especially its definitions and uses of "objective probability," its conception of space, the role it assigns to the macroworld in a universe governed by quantum laws, and its claim for the completeness of quantum mechanics. These issues are addressed.

Jan C. A. Boeyens