Witnessing quantum coherence in the presence of noise

We address the problem of assessing the coherent character of physical evolution. We take the quantum Zeno effect (QZE) as a characteristic trait of quantum dynamics, and derive relations among transfer rates as a function of the strength of a measurement. These relations support the intuition that only quantum dynamics is susceptible to the QZE. With the derived bounds on the magnitude of coherent dynamics, we propose an experimentally viable coherence witness. Our results have potential application in assessing the coherence of quantum transport in biological and other complex many-body systems.