SAMOP 2021 – scientific programme
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QI: Fachverband Quanteninformation
QI 9: Quantum Metrology
QI 9.6: Talk
Thursday, September 23, 2021, 12:30–12:45, H4
Metrological complementarity reveals the Einstein- Podolsky-Rosen paradox — •Benjamin Yadin1,2, Matteo Fadel3, and Manuel Gessner4 — 1School of Mathematical Sciences, University of Nottingham, Nottingham, UK — 2Wolfson College, University of Oxford, Oxford, UK — 3Department of Physics, University of Basel, Basel, Switzerland — 4Laboratoire Kastler Brossel, ENS-Université PSL, CNRS, Sorbonne Université, Collège de France, Paris, France
The Einstein-Podolsky-Rosen (EPR) paradox plays a fundamental role in our understanding of quantum mechanics, and is associated with the possibility of predicting the results of non-commuting measurements with a precision that seems to violate the uncertainty principle. This apparent contradiction to complementarity is made possible by nonclassical correlations stronger than entanglement, called steering. Quantum information recognises steering as an essential resource for a number of tasks but, contrary to entanglement, its role for metrology has so far remained unclear. Here, we formulate the EPR paradox in the framework of quantum metrology, showing that it enables the precise estimation of a local phase shift and of its generating observable. Employing a stricter formulation of quantum complementarity, we derive a criterion based on the quantum Fisher information that detects steering in a larger class of states than well-known uncertainty-based criteria. Our result identifies useful steering for quantum-enhanced precision measurements and allows one to uncover steering of non-Gaussian states in state-of-the-art experiments.