Three New Measures Quantify Dynamical Coherence of Quantum Channels

A theoretical study published in Quantum Information Processing introduces three measures of dynamical coherence of channels, generalizing several previous results in the field. Each of the three measures is based on a generalized distance-like function between channels, such as a quantum divergence of channels. The framework includes the relative entropy between channels and the diamond distance as instances of such distance-like functions.

The construction depends on the choice of free operations. The study considers three classes of free channels: detection-incoherent, creation-incoherent, and detection-creation incoherent channels. Because channels themselves can be transformed by higher-order maps, the framework also employs superchannels, which take one channel to another.

Free superchannels in this setting are constructed from free pre- and post-processing channels, so the operations applied before and after a given channel are themselves restricted to the free classes. The paper establishes two mathematical properties of the proposed measures. They are monotone under free superchannels, meaning that applying a free superchannel cannot increase the measured dynamical coherence of a channel, and they are convex, so mixing channels cannot inflate the measured resource.

The measures therefore generalize several earlier approaches while remaining compatible with different choices of free-operation classes and distance-like functions between channels. The study is theoretical and its results are mathematical properties of the proposed measures within the formalism of quantum information theory; the abstract does not report experimental demonstrations or applications to specific quantum devices.

Subject of Research: Measures of dynamical coherence for quantum channels based on channel divergences and free superchannels

Article Title: Dynamical coherence measures

Article References: Vershynina, A. (2026). Dynamical coherence measures. Quantum Information Processing, 25(11), Article 347. https://doi.org/10.1007/s11128-026-05375-y

Image Credits: AI Generated

DOI: 10.1007/s11128-026-05375-y

Keywords: quantum information, dynamical coherence, quantum channels, superchannels, relative entropy, diamond distance, free operations, monotonicity, convexity, resource theory, Dynamical, coherence