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 - Weighted graph states and applications to spin chains, lattices and gases
JF - Journal of Physics B: Atomic, Molecular and Optical Physics
Y1 - 2007
A1 - Hartmann, L.
A1 - Calsamiglia, John
A1 - Dür, Wolfgang
A1 - Briegel, Hans J.
VL - 40
UR - http://www.iop.org/EJ/abstract/0953-4075/40/9/S01
ER -
TY - JOUR
T1 - Quantum-information processing in disordered and complex quantum systems
JF - Physical Review A (Atomic, Molecular, and Optical Physics)
Y1 - 2006
A1 - Sen(De), Aditi
A1 - Sen, Ujjwal
A1 - Ahufinger, Veronica
A1 - Briegel, Hans J.
A1 - Sanpera, Anna
A1 - Lewenstein, Maciej
KW - information theory
KW - quantum entanglement
KW - quantum gates
KW - radiation pressure
VL - 74
UR - http://link.aps.org/abstract/PRA/v74/e062309
ER -
TY - JOUR
T1 - Spin Gases: Quantum Entanglement Driven by Classical Kinematics
JF - Physical Review Letters
Y1 - 2005
A1 - Calsamiglia, John
A1 - Hartmann, L.
A1 - Dür, Wolfgang
A1 - Briegel, Hans J.
KW - entanglement distribution
KW - spin gas
AB - A spin gas is a natural extension of a classical gas. It consists of a large number of particles whose (random) motion is described classically, but, in addition, have internal (quantum mechanical) degrees of freedom that interact during collisions. For specific types of quantum interactions we determine the entanglement that occurs naturally in such systems. We analyze how the evolution of the quantum state is determined by the underlying classical kinematics of the gas. For the Boltzmann gas, we calculate the rate at which entanglement is produced and characterize the entanglement properties of the equilibrium state.
VL - 95
UR - http://link.aps.org/abstract/PRL/v95/e180502
ER -