Quantifying Interference via Coherence
Yuan Sun, Shunlong Luo
Abstract
Abstract Interference, which has its origin in the superposition principle, is one of the hallmarks of wave mechanics and constitutes a versatile resource for many information processing tasks. As such, it is actually a manifestation of coherence. Despite its long history in the development of physics, quantitative studies of interference are still an important topic. Traditionally, interference is often characterized via the fringe visibility from an operational perspective. This is experimentally convenient. However, from a theoretic perspective, it is desirable to reveal information‐theoretic aspects of interference. In this work, coherence of a state (with respect to a unitary operator parameterized by the interfering paths and phase shifts in multi‐path interference) is first quantified in terms of a generalized version of the Wigner‐Yanase skew information, two natural quantifiers of interference are then introduced via this coherence measure. Basic properties of these quantifiers of interference are further revealed, and the concepts are illustrated through several examples.