Isotropic quantum spin channels and additivity questions

Abstract

The minimum entropy output is computed for rotationally invariant quantum channels acting on spin-1/2 and spin-1 systems. For the case of two parallel such channels and initial entangled (singlet) state the entropy of the output is higher then the doubled minimal entropy output of the single channel. This gives a certain moral support to the additivity hypothesis. Another related simple function of the channel (minimum entropy gain) is shown to be additive in general.

5 pages

Cited by in corpus (6)

• Quantum channels and their entropic characteristics
• On Hastings' counterexamples to the minimum output entropy additivity conjecture
• Approximate reversibility in the context of entropy gain, information gain, and complete positivity
• Measures of quantum correlations in infinite-dimensional systems
• Dependence of integrated, instantaneous, and fluctuating entropy production on the initial state in quantum and classical processes
• Estimating the output entropy of a tensor product of two quantum channels