01879nas a2200205 4500008003900000022001400039245004500053210004500098300001100143490000700154520131600161100001901477700002001496700002601516700002001542700001901562700002101581700001901602856005201621 2017 d a1367-263000aFlexible resources for quantum metrology0 aFlexible resources for quantum metrology a0630440 v193 aQuantum metrology offers a quadratic advantage over classical approaches to parameter estimation problems by utilising entanglement and nonclassicality. However, the hurdle of actually implementing the necessary quantum probe states and measurements, which vary drastically for different metrological scenarios, is usually not taken into account. We show that for a wide range of tasks in metrology, 2D cluster states (a particular family of states useful for measurement-based quantum computation) can serve as flexible resources that allow one to efficiently prepare any required state for sensing, and perform appropriate (entangled) measurements using only single qubit operations. Crucially, the overhead in the number of qubits is less than quadratic, thus preserving the quantum scaling advantage. This is ensured by using a compression to a logarithmically sized space that contains all relevant information for sensing. We specifically demonstrate how our method can be used to obtain optimal scaling for phase and frequency estimation in local estimation problems, as well as for the Bayesian equivalents with Gaussian priors of varying widths. Furthermore, we show that in the paradigmatic case of local phase estimation 1D cluster states are sufficient for optimal state preparation and measurement.1 aFriis, Nicolai1 aOrsucci, Davide1 aSkotiniotis, Michalis1 aSekatski, Pavel1 aDunjko, Vedran1 aBriegel, Hans, J1 aDür, Wolfgang uhttp://stacks.iop.org/1367-2630/19/i=6/a=063044