Interferometric visibility and coherence

Understand

Recently, the basic concept of quantum coherence (or superposition) has gained a lot of renewed attention, after Baumgratz et al.

• [PRL 113:140401 (2014)], following \AA{}berg [arXiv:quant-ph/0612146], have proposed a resource theoretic approach to quantify it.
• This has resulted in a large number of papers and preprints exploring various coherence monotones, and debating possible forms for the resource theory.
• Here we take the view that the operational foundation of coherence in a state, be it quantum or otherwise wave mechanical, lies in the observation of interference effects.