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Full-Text Articles in Physics
Pre- And Post-Selection Paradoxes And Contextuality In Quantum Mechanics, Matthew S. Leifer, Robert W. Spekkens
Pre- And Post-Selection Paradoxes And Contextuality In Quantum Mechanics, Matthew S. Leifer, Robert W. Spekkens
Mathematics, Physics, and Computer Science Faculty Articles and Research
Many seemingly paradoxical effects are known in the predictions for outcomes of intermediate measurements made on pre- and post-selected quantum systems. Despite appearances, these effects do not demonstrate the impossibility of a noncontextual hidden variable theory, since an explanation in terms of measurement disturbance is possible. Nonetheless, we show that for every paradoxical effect wherein all the pre- and post-selected probabilities are 0 or 1 and the pre- and post-selected states are nonorthogonal, there is an associated proof of the impossibility of a noncontextual hidden variable theory. This proof is obtained by considering all the measurements involved in the paradoxical …
Bell's Jump Process In Discrete Time, Jonathan Barrett, Matthew S. Leifer, Roderich Tumulka
Bell's Jump Process In Discrete Time, Jonathan Barrett, Matthew S. Leifer, Roderich Tumulka
Mathematics, Physics, and Computer Science Faculty Articles and Research
The jump process introduced by J. S. Bell in 1986, for defining a quantum field theory without observers, presupposes that space is discrete whereas time is continuous. In this letter, our interest is to find an analogous process in discrete time. We argue that a genuine analog does not exist, but provide examples of processes in discrete time that could be used as a replacement.