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PERIMETER INSTITUTE RECORDED SEMINAR ARCHIVE

In defense of the epistemic view of quantum states
Speaker(s): Robert Spekkens
Abstract: I present a toy theory that is based on a simple information-theoretic principle, namely, that in a state of maximal knowledge, there is a balance between one's knowledge and one's ignorance. The theory constitutes a local, non-contextual hidden variable theory wherein the object analogous to the quantum state is a probability distribution over the hidden variable. A wide variety of quantum phenomena, typically deemed mysterious, have analogues within the toy theory by the lights of which they appear intuitive. Such phenomena include: the non-commutativity of measurements; interference; no information gain without disturbance; the monogamy of entanglement; no cloning; no broadcasting; the possibility of remote steering; teleportation and dense coding; locally immeasurable product bases; and many others. The diversity and quality of the analogies with quantum theory provides compelling evidence for the view that quantum states are states of knowledge rather than states of reality. A consideration of the phenomena that the toy theory fails to reproduce, notably, violations of Bell inequalities and the existence of a Kochen-Specker theorem, provides clues for how to proceed with a research program wherein the epistemic interpretation of the quantum state is the idea upon which one never compromises.
Date: 21/05/2003 - 3:45 pm
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