High-resolution imaging with multi-parameter quantum metrology
Final Report Abstract
In this project we developed a general theory of quantum-enhanced imaging based on quantum multi-parameter estimation theory and applied it to passive satellite remote sensing. Here, the parameters that characterize the image are geometric properties of the sources, such as their sizes or positions, or brightnesses of pixels in the source plane. We found the optimal way of extracting the information in the resulting quantum state via an optimized unitary transformation that diagonalizes the symmetric logarithmic derivative. This leads to the most informative measurement, which turns out to be very generally photon-counting in optimized measurement modes. That measurement allows one to saturate the ultimate fundamental bound, a scalar quantum Cramér-Rao bound based on the contraction of the covariance matrix with an arbitrary positive-definite weight matrix. The weight matrix allows one to given different weights to different parts of the image, and hence can be used e.g. for zooming into different parts of the scene. Applied to the satellite, we showed that in the microwave domain a resolution better by an order of magnitude than what the classical diffraction limit given by the van Cittert-Zernike theorem predicts can be achieved. The results are robust even for relatively large photon losses and measurements that distinguish only between no photons and at least one photon. Even though the experimental realization will be challenging, requiring mode-mixing in a cryogenic environment and single-photon detectors in the microwave regime, this opens the road to substantial improvements in practically relevant scenarios, as well as to corresponding optimization schemes in other spectral ranges and for different imaging systems.
Publications
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Quantum-enhanced passive remote sensing. Physical Review A, 106(1).
Köse, Emre; Adesso, Gerardo & Braun, Daniel
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Superresolution imaging with multiparameter quantum metrology in passive remote sensing. Physical Review A, 107(3).
Köse, Emre & Braun, Daniel
