Imaging and parameter estimation underpin most of modern science, and the development of improved imaging techniques will have an extremely broad impact, scientifically and culturally. Current imaging techniques are limited by aperture size, losses, and system noise, but recent results show that the diffraction limit can be overcome by employing techniques from quantum metrology. The realisation of quantum-enhanced metrology requires reliable sources of large-scale entangled states. However, such states are extremely fragile and are easily destroyed by environmental noise. As such, demonstrations of quantum-enhanced sensing are presently limited to a laboratory setting.
Meanwhile, physicists are building ever-larger quantum networks, with the promise of secure communication and distributing quantum computing. Quantum networks provide resources that allow the transfer of quantum states from one location to another, where both phase and amplitude information is faithfully reproduced. Combining the spatially separated shared quantum resources of the Quantum Internet with the requirements of large-scale imaging, we can devise protocols that in principle achieve imaging resolution that is many orders of magnitude better.
In this theoretical proposal we develop the optimal architecture for performing 2D and 3D imaging and sensing on a quantum network, with the ability to mitigate loss and noise via dedicated quantum error correction protocols. In parallel, we will devise incoherent imaging processing methods, allowing one to achieve extremely large baselines, (e.g., the diameter of the Earth or larger) at optical frequencies. We first construct the theory for high-accuracy time measurements, which opens up the possibility to perform clock synchronization and perform target ranging/detection. Then we establish shared phase references between distant sites, allowing coherent processing of signals collected at far ends of our imaging aperture. Then, we will use large networks to perform imaging, integrated with loss and noise protection via quantum error correction. Lastly, we explore methods to train a quantum interferometer for object recognition for both thermal and entangled states. Thus, the project removes the current limitations of imaging and parameter estimation by measurement optimisation, as well as state optimisation (including quantum error correction).
This project has the ambitious goal of linking quantum imaging, quantum metrology and quantum communication, with a profound impact on the whole field of quantum technologies. It presents a novel, unified theory on large-baseline 2D and 3D quantum imaging and metrology that will be tightly combined with the experimental expertise of the Universities of Queensland (Australia), Erlangen (Germany), and Bristol (UK). The result will bring about low-noise detectors, highly accurate measurements, and super-resolved images, enabled by innovative experimental designs. The systems will be particularly suited to operate in a high-noise environment, with applications to stellar interferometry, and ranging; they will directly impact the UK's use of quantum information for cryptographic applications, navigation systems, field sensors, and communication technologies.
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