Interferometric Visibility and Coherence

Seminar date and time: 
Thursday, 31 August, 2017 - 14:30
IISER-Kolkata, India
Tanmoy Biswass
GIQ Seminar Room C5/262

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 ˚Aberg [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. Our approach here is to consider an idealized multi-path interferometer, with a suitable detector, in such a way that the visibility of the interference pattern provides a quantitative expression of the amount of coherence in a given probe state. We present a general framework of deriving coherence measures from visibility and demonstrate it by analyzing several concrete visibility parameters, recovering some known coherence measures.

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