A quantitative theory of coherent delocalization

Abstract

We define a quantitative measure of coherent delocalization; similarly to the concept of entanglement measures, we require that a measure of coherent delocalization may never increase under processes that do not create coherent superpositions. After a complete characterization of such processes, we prove that a set of recently introduced functions that characterize coherent delocalization never grow under such processes and thus are indeed valid measures.