Rényi Entropy, Signed Probabilities, and the Qubit

Adam Brandenburger, Pierfrancesco La Mura, Stuart Zoble

Published 2020-10-05Version 1

The states of the qubit, the basic unit of quantum information, are $2\times2$ positive semi-definite Hermitian matrices with trace $1$. We characterize these states in terms of an entropic uncertainty principle formulated on an eight-point phase space.