Christopher G. Timpson

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The Bayesian approach to quantummechanics of Caves, Fuchs and Schack is presented. Its conjunction of realism about physics along with antirealism about much of the structure of quantum theory is elaborated; and the position defended from common objections: that it is solipsist; that it is too instrumentalist; that it cannot deal with Wigner’s friend(More)
2 First steps with quantum information 3 2.1 Bits and qubits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.2 The no-cloning theorem . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.3 Quantum cryptography . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.3.1 Key Distribution . . . . . . . . . . . . . . . . . . . .(More)
In a comparison of the principles of special relativity and of quantum mechanics, the former theory is marked by its relative economy and apparent explanatory simplicity. A number of theorists have thus been led to search for a small number of postulates—essentially information theoretic in nature—that would play the role in quantum mechanics that the(More)
The distinction between proper and improper mixtures is a staple of the discussion of foundational questions in quantum mechanics. Here we note an analogous distinction in the context of the theory of entanglement. The terminology of ‘proper’ versus ‘improper’ separability is proposed to mark the distinction. 1 Proper and Improper mixtures In many(More)
Whilst a straightforward consequence of the formalism of non-relativistic quantum mechanics, the phenomenon of quantum teleportation has given rise to considerable puzzlement. In this paper, the teleportation protocol is reviewed and these puzzles dispelled. It is suggested that they arise from two primary sources: (1) the familiar error of hypostatizing an(More)
Recently, Brukner and Zeilinger have presented a number of arguments suggesting that the Shannon information is not well defined as a measure of information in quantum mechanics. If established, this result would be highly significant, as the Shannon information is fundamental to the way we think about information not only in classical but also in quantum(More)