Super-Resolution Imaging with Multiparameter Quantum Metrology in Passive Remote Sensing

TL;DR

This paper demonstrates theoretically that quantum metrology techniques can enhance the spatial resolution of passive remote sensing in the microwave regime, achieving ten times finer detail than current satellite systems.

Contribution

It provides a complete quantum mechanical framework for multiparameter estimation in super-resolution imaging, introducing optimal detection modes and a measurement scheme that saturates the quantum Cramér-Rao bound.

Findings

Achieved quantum-enhanced super-resolution with 3 km pixel size.

Optimal measurement modes improve resolution beyond classical limits.

Super-resolution persists even with non-optimized unitaries for specific images.

Abstract

We study super-resolution imaging theoretically using a distant n-mode interferometer in the microwave regime for passive remote sensing, used e.g., for satellites like the "soil moisture and ocean salinity (SMOS)" mission to observe the surface of the Earth. We give a complete quantum mechanical analysis of multiparameter estimation of the temperatures on the source plane. We find the optimal detection modes by combining incoming modes with an optimized unitary that enables the most informative measurement based on photon counting in the detection modes and saturates the quantum Cram\'er-Rao bound from the symmetric logarithmic derivative for the parameter set of temperatures. In our numerical analysis, we achieved a quantum-enhanced super-resolution by reconstructing an image using the maximum likelihood estimator with a pixel size of 3 km, which is ten times smaller than the spatial resolution of SMOS with comparable parameters. Further, we find the optimized unitary for uniform temperature distribution on the source plane, with the temperatures corresponding to the average temperatures of the image. Even though the corresponding unitary was not optimized for the specific image, it still gives a super-resolution compared to local measurement scenarios for the theoretically possible maximum number of measurements.