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Quantum Information and Entropy

Subhash Kak
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Abstract

Thermodynamic entropy is not an entirely satisfactory measure of information of a quantum state. This entropy for an unknown pure state is zero, although repeated measurements on copies of such a pure state do communicate information. In view of this, we propose a new measure for the informational entropy of a quantum state that includes information in the pure states and the thermodynamic entropy. The origin of information is explained in terms of an interplay between unitary and non-unitary evolution. Such complementarity is also at the basis of the so-called interaction-free measurement.

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Subhash Kak. 2006-05-10. Quantum Information and Entropy. https://doi.org/10.1007/s10773-006-9245-6

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