Heisenberg-Limited Atom Clocks Based on Entangled Qubits

E.  M. Kessler, P. Kómár, M. Bishof, L. Jiang, A.  S. Sørensen, J. Ye, M.  D. Lukin
Phys. Rev. Lett. 112, 190403 (2014)

The improvement of frequency standards using quantum resources, such as entanglement has been actively explored in recent years. The use of entangled resources, in principle, allows one to surpass the classical limit on precision. However, a characterization of the improvement obtainable by using entanglement requires a detailed investigation of the decoherence present in the system.

Joint estimation of phase and phase diffusion for quantum metrology

M. D. Vidrighin, G. Donati, M. G. Genoni, X.-M. Jin, W. S. Kolthammer, M. S. Kim, A. Datta, M. Barbieri, I. A. Walmsley
Nature Communications 5, 3532 (2014)

Phase estimation is one of the most studied quantum metrology situations, with wide-ranging practical applications. In many realistic situations, phase and phase diffusion may vary in time. Consequently, the accuracy of phase estimation may be affected by varying estimates of the magnitude of phase diffusion.

Using Entanglement Against Noise in Quantum Metrology

R. Demkowicz-Dobrzański, L. Maccone
Phys. Rev. Lett. 113, 250801 (2014)

Quantum metrology provides super-classical scaling in measurement precision by exploiting quantum effects. A crucial question in the field is to understand when entangled states lead to super-classical scaling.

Detecting nonlocality in many-body quantum states

J. Tura, R. Augusiak, A. B. Sainz, T. Vértesi, M. Lewenstein, and A. Acín
Science 344, 1256 (2014)

Fully device independent quantum key distribution

U. Vazirani, T. Vidick
Phys. Rev. Lett. 113, 140501 (2014)

Exponential improvement in precision for simulating sparse Hamiltonians

D. W. Berry, A. M. Childs, R. Cleve, R. Kothari, R. D. Somma
Proceedings of the 46th ACM Symposium on Theory of Computing (STOC 2014), 283-292 (2014)

Simulation of quantum mechanical systems is a major potential application of quantum computers. Indeed, the problem of simulating Hamiltonian dynamics was the original motivation for the idea of quantum computation.

Local tests of global entanglement and a counterexample to the generalized area law

D. Aharonov, A. W. Harrow, Z. Landau, D. Nagaj, M. Szegedy, U. Vazirani
Proceedings of FOCS 2014, 246 (2014)

Ultimate classical communication rates of quantum optical channels

V. Giovannetti, R. Garcia-Patrón, N. J. Cerf, A. S. Holevo
Nature Photonics 8, 796-800 (2014)

Measurement-Device-Independent Quantum Key Distribution over 200 km

Y-L. Tang, H-L. Yin, S-J.Chen, Y. Liu, W-J. Zhang, X. Jiang, L. Zhang, J. Wang, L-X. You, J-Y. Guan, D- X. Yang, Z. Wang, H. Liang, Z. Zhang, N. Zhou, X. Ma, T-Y. Chen, Q. Zhang, and J-W. Pan
Phys. Rev. Lett. 113, 190501 (2014)

Measurement-device–independent quantum key distribution (MDIQKD) represents a valid alternative for quantum cryptography. It requires fewer assumptions for security than standard prepare-and-measure schemes, while its implementation is less demanding than fully device-independent protocols.

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