PRA: Quantum information

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Recently published articles in Phys. Rev. A in the Table of Content section "Quantum information"
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Probabilistic quantum teleportation via thermal entanglement

Wed, 2017-08-16 16:00

Author(s): Raphael Fortes and Gustavo Rigolin

We study the probabilistic (conditional) teleportation protocol when the entanglement needed for its implementation is given by thermal entanglement, i.e., when the entangled resource connecting Alice and Bob is an entangled mixed state described by the canonical ensemble density matrix. Specificall...

[Phys. Rev. A 96, 022315] Published Wed Aug 16, 2017

Categories: Journals, Physics

Quantum illumination for enhanced detection of Rayleigh-fading targets

Tue, 2017-08-15 16:00

Author(s): Quntao Zhuang, Zheshen Zhang, and Jeffrey H. Shapiro

Quantum illumination (QI) is an entanglement-enhanced sensing system whose performance advantage over a comparable classical system survives its usage in an entanglement-breaking scenario plagued by loss and noise. In particular, QI's error-probability exponent for discriminating between equally lik...

[Phys. Rev. A 96, 020302(R)] Published Tue Aug 15, 2017

Categories: Journals, Physics

Fast quantum state engineering via universal SU(2) transformation

Tue, 2017-08-15 16:00

Author(s): Bi-Hua Huang, Yi-Hao Kang, Ye-Hong Chen, Qi-Cheng Wu, Jie Song, and Yan Xia

We introduce a simple yet versatile protocol to inverse engineer the time-dependent Hamiltonian in two- and three-level systems. In the protocol, by utilizing a universal SU(2) transformation, a given speedup goal can be obtained with large freedom to select the control parameters. As an illustratio...

[Phys. Rev. A 96, 022314] Published Tue Aug 15, 2017

Categories: Journals, Physics

Linear feedback stabilization of a dispersively monitored qubit

Mon, 2017-08-14 16:00

Author(s): Taylor Lee Patti, Areeya Chantasri, Luis Pedro García-Pintos, Andrew N. Jordan, and Justin Dressel

The state of a continuously monitored qubit evolves stochastically, exhibiting competition between coherent Hamiltonian dynamics and diffusive partial collapse dynamics that follow the measurement record. We couple these distinct types of dynamics together by linearly feeding the collected record fo...

[Phys. Rev. A 96, 022311] Published Mon Aug 14, 2017

Categories: Journals, Physics

Optimal discrimination of single-qubit mixed states

Mon, 2017-08-14 16:00

Author(s): Graeme Weir, Stephen M. Barnett, and Sarah Croke

We consider the problem of minimum-error quantum state discrimination for single-qubit mixed states. We present a method which uses the Helstrom conditions constructively and analytically; this algebraic approach is complementary to existing geometric methods, and solves the problem for any number o...

[Phys. Rev. A 96, 022312] Published Mon Aug 14, 2017

Categories: Journals, Physics

Monogamy inequalities for certifiers of continuous-variable Einstein-Podolsky-Rosen entanglement without the assumption of Gaussianity

Mon, 2017-08-14 16:00

Author(s): L. Rosales-Zárate, R. Y. Teh, B. Opanchuk, and M. D. Reid

We consider three modes A, B, and C and derive monogamy inequalities that constrain the distribution of bipartite continuous variable Einstein-Podolsky-Rosen entanglement amongst the three modes. The inequalities hold without the assumption of Gaussian states, and are based on measurements of the qu...

[Phys. Rev. A 96, 022313] Published Mon Aug 14, 2017

Categories: Journals, Physics

Secure alignment of coordinate systems using quantum correlation

Fri, 2017-08-11 16:00

Author(s): F. Rezazadeh, A. Mani, and V. Karimipour

We show that two parties far apart can use shared entangled states and classical communication to align their coordinate systems with a very high fidelity. Moreover, compared with previous methods proposed for such a task, i.e., sending parallel or antiparallel pairs or groups of spin states, our me...

[Phys. Rev. A 96, 022310] Published Fri Aug 11, 2017

Categories: Journals, Physics

Robust <span class="sc">not</span> gate by single-shot-shaped pulses: Demonstration of the efficiency of the pulses in rephasing atomic coherences

Thu, 2017-08-10 16:00

Author(s): Leo Van-Damme, Daniel Schraft, Genko T. Genov, Dominique Sugny, Thomas Halfmann, and Stéphane Guérin

We derive a versatile protocol to implement a fast and robust not quantum gate, driven by single-shot-shaped pulses with appropriate time-dependent phase and intensity profiles. The pulses are derived by combining analytic computations and numerical optimizations. We experimentally demonstrate the a...

[Phys. Rev. A 96, 022309] Published Thu Aug 10, 2017

Categories: Journals, Physics

Qubit entanglement across $ε$-near-zero media

Wed, 2017-08-09 16:00

Author(s): S.-A. Biehs and G. S. Agarwal

Currently, epsilon-near-zero (ENZ) materials have become important for controlling the propagation of light and enhancing by several orders of magnitude the Kerr and other nonlinearities. Given this advance it is important to examine the quantum electrodynamic processes and information tasks near EN...

[Phys. Rev. A 96, 022308] Published Wed Aug 09, 2017

Categories: Journals, Physics

Symmetry-protected topological order at nonzero temperature

Mon, 2017-08-07 16:00

Author(s): Sam Roberts, Beni Yoshida, Aleksander Kubica, and Stephen D. Bartlett

We address the question of whether symmetry-protected topological (SPT) order can persist at nonzero temperature, with a focus on understanding the thermal stability of several models studied in the theory of quantum computation. We present three results in this direction. First, we prove that nontr...

[Phys. Rev. A 96, 022306] Published Mon Aug 07, 2017

Categories: Journals, Physics

Einstein-Podolsky-Rosen-steering swapping between two Gaussian multipartite entangled states

Mon, 2017-08-07 16:00

Author(s): Meihong Wang, Zhongzhong Qin, Yu Wang, and Xiaolong Su

Multipartite Einstein-Podolsky-Rosen (EPR) steering is a useful quantum resource for quantum communication in quantum networks. It has potential applications in secure quantum communication, such as one-sided device-independent quantum key distribution and quantum secret sharing. By distributing opt...

[Phys. Rev. A 96, 022307] Published Mon Aug 07, 2017

Categories: Journals, Physics

Complete Bell-state analysis for superconducting-quantum-interference-device qubits with a transitionless tracking algorithm

Fri, 2017-08-04 16:00

Author(s): Yi-Hao Kang, Ye-Hong Chen, Zhi-Cheng Shi, Bi-Hua Huang, Jie Song, and Yan Xia

We propose a protocol for complete Bell-state analysis for two superconducting-quantum-interference-device qubits. The Bell-state analysis could be completed by using a sequence of microwave pulses designed by the transitionless tracking algorithm, which is a useful method in the technique of shortc...

[Phys. Rev. A 96, 022304] Published Fri Aug 04, 2017

Categories: Journals, Physics

Arbitrary multimode Gaussian operations on mechanical cluster states

Fri, 2017-08-04 16:00

Author(s): Darren W. Moore, Oussama Houhou, and Alessandro Ferraro

We consider opto- and electromechanical quantum systems composed of a driven cavity mode interacting with a set of mechanical resonators. It has been proposed that the latter can be initialized in arbitrary cluster states, including universal resource states for measurement-based quantum computation...

[Phys. Rev. A 96, 022305] Published Fri Aug 04, 2017

Categories: Journals, Physics

Approximate broadcasting of quantum correlations

Thu, 2017-08-03 16:00

Author(s): Wei Xie, Kun Fang, Xin Wang, and Runyao Duan

Broadcasting quantum and classical information is a basic task in quantum information processing, and is also a useful model in the study of quantum correlations including quantum discord. We establish a full operational characterization of two-sided quantum discord in terms of bilocal broadcasting ...

[Phys. Rev. A 96, 022302] Published Thu Aug 03, 2017

Categories: Journals, Physics

Sequential scheme for locally discriminating bipartite unitary operations without inverses

Thu, 2017-08-03 16:00

Author(s): Lvzhou Li

Local distinguishability of bipartite unitary operations has recently received much attention. A nontrivial and interesting question concerning this subject is whether there is a sequential scheme for locally discriminating between two bipartite unitary operations, because a sequential scheme usuall...

[Phys. Rev. A 96, 022303] Published Thu Aug 03, 2017

Categories: Journals, Physics

Exact boson sampling using Gaussian continuous-variable measurements

Wed, 2017-08-02 16:00

Author(s): A. P. Lund, S. Rahimi-Keshari, and T. C. Ralph

Boson sampling is a quantum mechanical task involving Fock basis state preparation and detection and evolution using only linear interactions. A classical algorithm for producing samples from this quantum task cannot be efficient unless the polynomial hierarchy of complexity classes collapses, a sit...

[Phys. Rev. A 96, 022301] Published Wed Aug 02, 2017

Categories: Journals, Physics

Quantum parameter estimation with the Landau-Zener transition

Tue, 2017-08-01 16:00

Author(s): Jing Yang, Shengshi Pang, and Andrew N. Jordan

We investigate the fundamental limits in precision allowed by quantum mechanics from Landau-Zener transitions, concerning Hamiltonian parameters. While the Landau-Zener transition probabilities depend sensitively on the system parameters, much more precision may be obtained using the acquired phase,...

[Phys. Rev. A 96, 020301(R)] Published Tue Aug 01, 2017

Categories: Journals, Physics

Quantum coherence of planar spin models with Dzyaloshinsky-Moriya interaction

Mon, 2017-07-31 16:00

Author(s): Chandrashekar Radhakrishnan, Igor Ermakov, and Tim Byrnes

The quantum coherence of one-dimensional planar spin models with Dzyaloshinsky-Moriya interaction is investigated. The anisotropic XY model, the isotropic XX model, and the transverse field model are studied in the large N limit using two qubit reduced density matrices and two point correlation func...

[Phys. Rev. A 96, 012341] Published Mon Jul 31, 2017

Categories: Journals, Physics

Quantum algorithm for linear regression

Mon, 2017-07-31 16:00

Author(s): Guoming Wang

We present a quantum algorithm for fitting a linear regression model to a given data set using the least-squares approach. Differently from previous algorithms which yield a quantum state encoding the optimal parameters, our algorithm outputs these numbers in the classical form. So by running it onc...

[Phys. Rev. A 96, 012335] Published Mon Jul 31, 2017

Categories: Journals, Physics

Genuine multipartite nonlocality in the one-dimensional ferromagnetic spin-1/2 chain

Mon, 2017-07-31 16:00

Author(s): Yue Dai, Chengjie Zhang, Wenlong You, Yuli Dong, and C. H. Oh

Genuine multipartite entanglement has been found in some spin chain systems. However, genuine multipartite nonlocality is much rarer than genuine multipartite entanglement. Here we present genuine multipartite nonlocality in a spin chain system. After introducing the definition of genuine multiparti...

[Phys. Rev. A 96, 012336] Published Mon Jul 31, 2017

Categories: Journals, Physics