Flexible resources for quantum metrology

Flexible resources for quantum metrology

Seminar author:Davide Orsucci

Event date and time:11/18/2016 02:30:pm

Event location:GIQ - Seminar room

Event contact:

Quantum metrology grants a quadratic advantage over classical approaches to parameter estimation exploiting entanglement and nonclassicality. Customarily, however, the hurdle of actually implementing the necessary quantum probe states and quantum measurements is usually not taken into account, and moreover in different metrological scenarios the required states and measurements vary. We show that measurement-based computation over 2D cluster states is a universal method to efficiently prepare the optimal resource states and to perform the appropriate measurements by means of only local operations on part of the system, while the remaining qubits are used for sensing. Crucially, the overhead is only poly-logarithmic, thus preserving the advantage inherent to quantum strategies over the classical ones. 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.