Detecting multipartite entanglement and EPR steering with tools from metrology

Seminar author:Manuel Gessner

Event date and time:11/25/2021 04:00:pm

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The sensitivity of quantum states under small perturbations is the quantity of central interest in quantum metrology. Besides identifying strategies that lead to quantum-enhanced measurement precision, the metrological sensitivity provides detailed information about the state’s quantum correlations. We discuss metrological witnesses that reveal the multipartite entanglement structure, generalizing entanglement depth and k-separability. Furthermore, we use a metrological complementarity relation to formulate the Einstein-Podolsky-Rosen (EPR) paradox and to build a witness for EPR steering, a stronger form of entanglement. Metrological entanglement witnesses are able to capture delicate features of non-Gaussian quantum states and can be systematically optimized given any set of measurable observables.