Physics

Quantification of concurrence via weak measurement

PRA: Quantum information - Mon, 2017-05-01 16:00

Author(s): Mikko Tukiainen, Hirokazu Kobayashi, and Yutaka Shikano

Since entanglement is not an observable per se, measuring its value in practice is a difficult task. Here we propose a protocol for quantifying a particular entanglement measure, namely, concurrence, of an arbitrary two-qubit pure state via a single fixed measurement setup by exploiting so-called we...


[Phys. Rev. A 95, 052301] Published Mon May 01, 2017

Categories: Journals, Physics

Robust continuous-variable quantum key distribution against practical attacks

PRA: Quantum information - Mon, 2017-05-01 16:00

Author(s): Peng Huang, Jingzheng Huang, Tao Wang, Huasheng Li, Duan Huang, and Guihua Zeng

Recently, several practical attacks on continuous-variable quantum key distribution (CVQKD) were proposed based on faking the estimated value of channel excess noise to hide the intercept-and-resend eavesdropping strategy, including the local oscillator (LO) fluctuation, calibration, wavelength, and...


[Phys. Rev. A 95, 052302] Published Mon May 01, 2017

Categories: Journals, Physics

Generation of robust tripartite entanglement with a single-cavity optomechanical system

PRA: Quantum information - Mon, 2017-05-01 16:00

Author(s): Xihua Yang, Yang Ling, Xuping Shao, and Min Xiao

We present a proposal to generate robust tripartite optomechanical entanglement with a single-cavity optomechanical system driven by a single input laser field. The produced stationary tripartite entanglement among two longitudinal cavity modes and a mirror oscillation mode via radiation pressure fo...


[Phys. Rev. A 95, 052303] Published Mon May 01, 2017

Categories: Journals, Physics

Continuous measurement of an atomic current

Author(s): C. Laflamme, D. Yang, and P. Zoller

We are interested in dynamics of quantum many-body systems under continuous observation, and its physical realizations involving cold atoms in lattices. In the present work we focus on continuous measurement of atomic currents in lattice models, including the Hubbard model. We describe a Cavity QED …


[Phys. Rev. A 95, 043843] Published Fri Apr 28, 2017

Categories: Journals, Physics

Description of spontaneous photon emission and local density of states in the presence of a lossy polaritonic inhomogeneous medium

Author(s): Aurélien Drezet

We provide a description of spontaneous emission in a dispersive and dissipative linear inhomogeneous medium based on the generalized Huttner-Barnett model [Phys. Rev. A 46, 4306 (1992)]. Our discussion considers on an equal footing both the photonic and material fluctuations which are necessary to …


[Phys. Rev. A 95, 043844] Published Fri Apr 28, 2017

Categories: Journals, Physics

Anderson Localization of Ultracold Atoms: Where is the Mobility Edge?

Author(s): Michael Pasek, Giuliano Orso, and Dominique Delande

Recent experiments in noninteracting ultracold atoms in three-dimensional speckle potentials have yielded conflicting results regarding the so-called mobility edge, i.e., the energy threshold separating Anderson localized from diffusive states. At the same time, there are theoretical indications tha...


[Phys. Rev. Lett. 118, 170403] Published Fri Apr 28, 2017

Categories: Journals, Physics

Feature: Research News: Editors’ Choice

APS Physics - Fri, 2017-04-28 16:00

Magnets that mimic Higgs decays, a Venus look-alike, and more in our monthly wrap-up of papers from the physics literature.


[Physics 10, 46] Published Fri Apr 28, 2017

Categories: Physics

Focus: 3D Images 10 Times Faster

APS Physics - Fri, 2017-04-28 16:00

Author(s): Katherine Wright

3D x-ray phase-contrast images take as little as one-tenth the usual time to acquire using a technique that halves the number of required “photos.”


[Physics 10, 48] Published Fri Apr 28, 2017

Categories: Physics

Algorithm for the solution of the Dirac equation on digital quantum computers

PRA: Quantum information - Fri, 2017-04-28 16:00

Author(s): François Fillion-Gourdeau, Steve MacLean, and Raymond Laflamme

A quantum algorithm that solves the time-dependent Dirac equation on a digital quantum computer is developed and analyzed. The time evolution is performed by an operator-splitting decomposition technique that allows for a mapping of the Dirac operator to a quantum walk supplemented by unitary rotati...


[Phys. Rev. A 95, 042343] Published Fri Apr 28, 2017

Categories: Journals, Physics

Device-independent quantum private query

PRA: Quantum information - Fri, 2017-04-28 16:00

Author(s): Arpita Maitra, Goutam Paul, and Sarbani Roy

In quantum private query (QPQ), a client obtains values corresponding to his or her query only, and nothing else from the server, and the server does not get any information about the queries. V. Giovannetti et al. [Phys. Rev. Lett. 100, 230502 (2008)] gave the first QPQ protocol and since then qui...


[Phys. Rev. A 95, 042344] Published Fri Apr 28, 2017

Categories: Journals, Physics

Measuring the Berry phase in a superconducting phase qubit by a shortcut to adiabaticity

PRA: Quantum information - Fri, 2017-04-28 16:00

Author(s): Zhenxing Zhang, Tenghui Wang, Liang Xiang, Jiadong Yao, Jianlan Wu, and Yi Yin

A scheme for fast measurements of geometrical phases in a superconducting qubit platform is demonstrated. The result might boost developments in quantum computation.


[Phys. Rev. A 95, 042345] Published Fri Apr 28, 2017

Categories: Journals, Physics

Effects of noninstantaneous nonlinear processes on photon-pair generation by spontaneous four-wave mixing

Author(s): Jacob G. Koefoed, Jesper B. Christensen, and Karsten Rottwitt

We present a general model, based on a Hamiltonian approach, for the joint quantum state of photon pairs generated through pulsed spontaneous four-wave mixing, including nonlinear phase modulation and a finite material response time. For the case of a silica fiber, it is found that the pair-producti…


[Phys. Rev. A 95, 043842] Published Thu Apr 27, 2017

Categories: Journals, Physics

Synopsis: Beam Splitter is Printed On-Demand

APS Physics - Thu, 2017-04-27 16:00

3D printing enables researchers to quickly fabricate a complex part for a molecular beam experiment.


[Physics] Published Thu Apr 27, 2017

Categories: Physics

Protecting entanglement from finite-temperature thermal noise via weak measurement and quantum measurement reversal

PRA: Quantum information - Thu, 2017-04-27 16:00

Author(s): Wen-Jie Zou, Yu-Huai Li, Shu-Chao Wang, Yuan Cao, Ji-Gang Ren, Juan Yin, Cheng-Zhi Peng, Xiang-Bin Wang, and Jian-Wei Pan

In practical applications, quantum systems work in a finite-temperature environment. Quantum entanglement is inevitably destroyed by the thermal noise. Here we experimentally demonstrate the protection of entanglement on the platform of linear optics. The finite-temperature thermal noise is describe...


[Phys. Rev. A 95, 042342] Published Thu Apr 27, 2017

Categories: Journals, Physics
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