Optimising quantum sensors by estimation theory and dynamical control tools

ANALIA ZWICK; GONZALO A. ALVAREZ; GERSHON KURIZKI

Buenos Aires

Congreso; Frontiers In Physical Sciences; 2016

ICAS, Humboldt, Max Planck

Controlled quantum spins are sensitive probes of the environment and a powerful tool for characterizing highly complex quantum systems at a molecular or atomic scale. Novel quantum technologies requiring high sensitivity at the nanoscale are based on quantum spin probes serving as magnetometers, thermometers, sensors for imaging or monitoring biological process. We explore the ability of a qubit probe to characterize unknown parameters of its environment. By resorting to quantum estimation theory, we analytically find the ultimate bound on the precision of estimating key parameters of a broad class of ubiquitous environmental noises which the qubit may probe. By optimizing the dynamical control on the probe under realistic constraints one may attain the maximal accuracy bound on the estimation of these parameters by the least number of measurements possible. Applications of this protocol that combines dynamical control and estimation theory tools to quantum sensing are illustrated for a nitrogen-vacancy center in diamond used as a probe.