TY - JOUR
T1 - Measurements in two bases are sufficient for certifying high-dimensional entanglement
JF - Nature Physics
Y1 - 2018
A1 - Bavaresco, Jessica
A1 - Herrera Valencia, Natalia
A1 - Klockl, Claude
A1 - Pivoluska, Matej
A1 - Erker, Paul
A1 - Friis, Nicolai
A1 - Malik, Mehul
A1 - Huber, Marcus
VL - 14
UR - http://www.nature.com/articles/s41567-018-0203-zhttp://www.nature.com/articles/s41567-018-0203-z.pdfhttp://www.nature.com/articles/s41567-018-0203-zhttp://www.nature.com/articles/s41567-018-0203-z.pdf
JO - Nature Phys
ER -
TY - JOUR
T1 - Flexible resources for quantum metrology
JF - New Journal of Physics
Y1 - 2017
A1 - Friis, Nicolai
A1 - Orsucci, Davide
A1 - Skotiniotis, Michalis
A1 - Sekatski, Pavel
A1 - Dunjko, Vedran
A1 - Briegel, Hans J.
A1 - Dür, Wolfgang
AB - Quantum 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.
VL - 19
UR - http://stacks.iop.org/1367-2630/19/i=6/a=063044
ER -
TY - JOUR
T1 - Thermodynamics of creating correlations: {Limitations} and optimal protocols
JF - Physical Review E
Y1 - 2015
A1 - Bruschi, David Edward
A1 - Martí Perarnau-Llobet
A1 - Friis, Nicolai
A1 - Karen V. Hovhannisyan
A1 - Huber, Marcus
VL - 91
UR - http://link.aps.org/doi/10.1103/PhysRevE.91.032118
ER -