Universal Quantum Magnetometry with Spin States at Equilibrium

Speaker:Matteo Paris

Title:Universal Quantum Magnetometry with Spin States at Equilibrium

Time:10:30am.  July 18th,2019

Location:725 Conference Room


Matteo Paris is full professor at the Department of Physics, University of Milano, where he founded and lead the Applied Quantum Mechanics research group (http://users.unimi.it/aqm), currently composed of twenty people, carrying on theoretical and experimental research on quantum technology, quantum optics and foundations of quantum mechanics.

He is a theoretician working in close collaborations with experimentalists on quantum information, quantum optics and foundations of quantum mechanics. In these fields he is author of about 300 publications on international journals, which

received more than 8500 citations, with about 60 invited talks and seminars; his

h-index is currently 47 (Google scholar). His main contributions are in the fields of quantum estimation of states and operations, generation and application of

entanglement and more general quantum correlations, quantum information processing, open quantum systems, interferometry and high-precision measurements.



We address metrological protocols for the estimation of the intensity and the orientation of a magnetic field, and show that quantum-enhanced precision may be achieved by probing the field with an arbitrary spin at thermal equilibrium. A general expression is derived for the ultimate achievable precision, as given by the quantum Fisher information. The optimal observable is shown to correspond to the spin projection along a temperature-dependent direction, and allows a maximally precise parameter estimation also through ensemble measurements. Finally, we prove the robustness of our scheme against deviations of the measured spin projection from optimality.