



01637nas a2200181   4500008004100000022001400041245010300055210006900158260001300227490000600240520106000246100002201306700002001328700002101348700002401369700002501393856003701418       2021                        eng d  a2643-156400aProtocols for estimating multiple functions with quantum sensor networks: Geometry and performance0 aProtocols for estimating multiple functions with quantum sensor   c5/3/20210 v33 a<p>We consider the problem of estimating multiple analytic functions of a set of local parameters via qubit sensors in a quantum sensor network. To address this problem, we highlight a generalization of the sensor symmetric performance bounds of Rubio et. al. [J. Phys. A: Math. Theor. 53 344001 (2020)] and develop a new optimized sequential protocol for measuring such functions. We compare the performance of both approaches to one another and to local protocols that do not utilize quantum entanglement, emphasizing the geometric significance of the coefficient vectors of the measured functions in determining the best choice of measurement protocol. We show that, in many cases, especially for a large number of sensors, the optimized sequential protocol results in more accurate measurements than the other strategies. In addition, in contrast to the the sensor symmetric approach, the sequential protocol is known to always be explicitly implementable. The sequential protocol is very general and has a wide range of metrological applications.</p>1 aBringewatt, Jacob1 aBoettcher, Igor1 aNiroula, Pradeep1 aBienias, Przemyslaw1 aGorshkov, Alexey, V.  uhttps://arxiv.org/abs/2104.09540