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Register a new userDemonstrating an absolute quantum advantage in direct absorption measurement
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Added by
Paul-Antoine Moreau Dr.
Publication date
2016
fields
Physics
and research's language is
English
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Engineering apparatus that harness quantum theory offers practical advantages over current technology. A fundamentally more powerful prospect is the long-standing prediction that such quantum technologies could out-perform any future iteration of their classical counterparts, no matter how well the attributes of those classical strategies can be improved. Here, we experimentally demonstrate such an instance of textit{absolute} advantage per photon probe in the precision of optical direct absorption measurement. We use correlated intensity measurements of spontaneous parametric downconversion using a commercially available air-cooled CCD, a new estimator for data analysis and a high heralding efficiency photon-pair source. We show this enables improvement in the precision of measurement, per photon probe, beyond what is achievable with an ideal coherent state (a perfect laser) detected with $100%$ efficient and noiseless detection. We see this absolute improvement for up to $50%$ absorption, with a maximum observed factor of improvement of 1.46. This equates to around $32%$ reduction in the total number of photons traversing an optical sample, compared to any future direct optical absorption measurement using classical light.
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