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Quantum Metrology & Sensing - QMET

by Sebastien_Tanzilli - published on , updated on

- Leaders

Nicolas Treps , Pascal Degiovanni , & Sébastien Tanzilli

- Aims of this thematic

Quantum data processing and communication require that tasks are performed coherently.

On one hand, quantum measurements play a crucial role for quantum information processing, both for the read-out of the final state of the results and the preparation of a well-defined initial state. Highly sophisticated measurement procedures have been developed and continue to be developed to achieve reliable measurements on the single qubit level (which may signify measuring the quantum state of a single atom, photon, or impurity in a solid). Furthermore, considerable efforts are dedicated to the increase of resolution of these apparatus, meaning their ability to differentiate as many quantum states as possible (for instance the exact number of photons). The idealized projective measurements postulated in the axioms of quantum mechanics do not necessarily correspond to the real experimental world. There is a sustained effort, both theoretical and experimental, to generalize these concepts (such as back-action avoiding measurements, weak measurements, feed-back schemes, etc). At the same time, quantum-information theoretical protocols have brought new insights for precision measurements of classical observables (“quantum enhanced measurements”), which typically use non-classical states, such as squeezed light. The goal is to derive optimal measurements and to improve the sensitivity of measurement schemes.

On the other hand, decoherence describes the loss of quantum coherence due to the build up of correlations between the carrying system and the environment. Beyond its fundamental interest, the study of decoherence is necessary to know the conditions of possibility of quantum computation, and to develop strategies to reach them.Retour ligne automatique
Hence, the scope of this topics is as well fundamental (quantum-classical boundary, link with entanglement and complementarity, etc.), as applied (protection schemes against decoherence, controlling the environment to exploit decoherence when it is considered as a resource, etc.).

- Bibliography for all

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- Reports: state-of-the-art and future

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