Heisenberg-Scaling Measurement Protocol for Analytic Functions with Quantum Sensor Networks

Understand

We generalize past work on quantum sensor networks to show that, for $d$ input parameters, entanglement can yield a factor $\mathcal O(d)$ improvement in mean squared error when estimating an analytic function of these parameters.

• We show that the protocol is optimal for qubit sensors, and conjecture an optimal protocol for photons passing through interferometers.
• Our protocol is also applicable to continuous variable measurements, such as one quadrature of a field operator.
• We outline a few potential applications, including calibration of laser operations in trapped ion quantum computing.