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QuantIC researcher Animesh Datta and his group at the University of Warwick recently published two papers on measuring multiple parameters simultaneously – something seemingly prohibited by quantum mechanics, which moves forward thinking on the future of quantum enhanced imaging.
Animesh said, “Today, a picture taken by a camera on a typical smartphone can consist of more than 10 megapixels. This is the reality of modern-day cameras and imaging. The ability of record millions of pixels simultaneously will therefore be expected to be a necessary part of any future imaging technology as a matter of course. And that includes quantum enhanced strategies. Measuring (or estimating) multiple parameters simultaneously, however, is fundamentally limited by quantum mechanics. It is one of the characteristics that sets quantum mechanics apart from classical physics.”
In Multi-parameter quantum metrology (M.Szczykulska, T.Baumgratz, A.Datta), published in Advances in Physics: X, Animesh looks at the simultaneous quantum estimation of multiple parameters and reviews the rich background of quantum-limited local estimation theory of multiple parameters that underlie these advances and discusses some of the main results in the field and its recent progress. In Gaussian systems for quantum-enhanced multiple phase estimation (C.N. Gagatsos, D. Branford, A. Datta), published in APS Physical Review A, he shows that using suitably designed quantum probe states (for instance, of light) not only can one circumvent some of the limits that were thought to be inviolable, but also obtain improved performance as compared to estimating the parameters individually.
He added, “The results show that Nature is more subtle than anticipated. While we can trick Nature to allow us to estimate multiple phases (say pixels) simultaneously, Nature now seems to tie our hands as to how well we can do. Using only Gaussian states, which are most easily and routinely generated in laboratories by lasers and down-converters, there is only a factor-of-2 improvement.” This factor-of-2 improvement appears to be a fundamental limit in the estimation of multiple phases simultaneously and shows that quantum enhanced imaging necessitates a deeper understanding of the quantum properties of Nature itself.
To read the paper on Multi-parameter quantum metrology, click here.
To read the paper on Gaussian systems for quantum-enhanced multiple phase estimation, click here.