TY - JOUR T1 - Optimal and Secure Measurement Protocols for Quantum Sensor Networks Y1 - 2018 A1 - Zachary Eldredge A1 - Michael Foss-Feig A1 - Steven L. Rolston A1 - Alexey V. Gorshkov AB -

Studies of quantum metrology have shown that the use of many-body entangled states can lead to an enhancement in sensitivity when compared to product states. In this paper, we quantify the metrological advantage of entanglement in a setting where the quantity to be measured is a linear function of parameters coupled to each qubit individually. We first generalize the Heisenberg limit to the measurement of non-local observables in a quantum network, deriving a bound based on the multi-parameter quantum Fisher information. We then propose a protocol that can make use of GHZ states or spin-squeezed states, and show that in the case of GHZ states the procedure is optimal, i.e., it saturates our bound.

UR - http://arxiv.org/abs/1607.04646 U5 - https://doi.org/10.1103/PhysRevA.97.042337 ER -