We construct for a Schur concave function f on the set of quantum states a tight upper bound on the difference f(ρ)−f(σ) for a quantum state ρ with finite f(ρ) and any quantum state σm-partially majorized by the state ρ in the sense described in [1]. We also obtain a tight upper bound on this difference under the additional condition 21∥ρ−σ∥1≤ε and find simple sufficient conditions for vanishing this bound with min{ε,1/m}→0.
The obtained results are applied to the von Neumann entropy. The concept of ε-sufficient majorization rank of a quantum state with finite entropy is introduced and a tight upper bound on this quantity is derived and applied to the Gibbs states of a quantum oscillator.
We also show how the obtained results can be reformulated for Schur concave functions on the set of probability distributions with a finite or countable set of outcomes.
Abstract. We show how to determine the maximum and minimum possible values of one measure of entropy for a given value of another measure of entropy. These maximum and minimum values are obtained for two standard forms of probability distribution (or quantum state) independent of the entropy measures, provided the entropy measures satisfy a concavity/convexity relation. These results may be applied to entropies for classical probability distributions, entropies of mixed quantum states and measures of entanglement for pure states. PACS numbers: 03.67.–a
We show how to determine the maximum and minimum possible values of one measure of entropy for a given value of another measure of entropy. These maximum and minimum values are obtained for two standard forms of probability distribution (or quantum state) independent of the entropy measures, provided the entropy measures satisfy a concavity/convexity relation. These results may be applied to entropies for classical probability distributions, entropies of mixed quantum states and measures of entanglement for pure states.