Phase-covariant mixtures of non-unital qubit maps

Abstract

We analyze convex combinations of non-unital qubit maps that are phase-covariant. In particular, we consider the behavior of maps that combine amplitude damping, inverse amplitude damping, and pure dephasing. We show that mixing non-unital channels can result in restoring the unitality, whereas mixing commutative maps can lead to non-commutativity. For the convex combinations of Markovian semigroups, we prove that classical uncertainties cannot break quantum Markovianity. Moreover, contrary to the Pauli channel case, the semigroup can be recovered only by mixing two other semigroups.

References in corpus (8)

• Assessing non-Markovian dynamics
• Structure of completely positive quantum master equations with memory kernel
• Divisibility of quantum dynamical maps and collision models
• All-optical non-Markovian stroboscopic quantum simulator
• On Weyl channels being covariant with respect to the maximum commutative group of unitaries
• Markovian semigroup from mixing non-invertible dynamical maps
• Noninvertibility as a requirement for creating a semigroup under convex combinations of channels
• Non-Markovianity criteria for mixtures of noninvertible Pauli dynamical maps

Cited by in corpus (2)

• Enhancing phase-covariant channel performance with non-unitality
• Digital simulation of convex mixtures of Markovian and non-Markovian single qubit Pauli channels on NISQ devices