PRA: Quantum information

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Recently published articles in Phys. Rev. A in the Table of Content section "Quantum information"
Updated: 16 min 15 sec ago

Two-photon self-Kerr nonlinearities for quantum computing and quantum optics

Mon, 2018-12-10 11:00

Author(s): Joshua Combes and Daniel J. Brod

The self-Kerr interaction is an optical nonlinearity that produces a phase shift proportional to the square of the number of photons in the field. At present, many proposals use nonlinearities to generate photon-photon interactions. For propagating fields these interactions result in undesirable fea...


[Phys. Rev. A 98, 062313] Published Mon Dec 10, 2018

Categories: Journals, Physics

Simulating arbitrary Gaussian circuits with linear optics

Mon, 2018-12-10 11:00

Author(s): L. Chakhmakhchyan and N. J. Cerf

Linear canonical transformations of bosonic modes correspond to Gaussian unitaries, which comprise passive linear-optical transformations as effected by a multiport passive interferometer and active Bogoliubov transformations as effected by a nonlinear amplification medium. As a consequence of the B...


[Phys. Rev. A 98, 062314] Published Mon Dec 10, 2018

Categories: Journals, Physics

Steering random spin systems to speed up the quantum adiabatic algorithm

Fri, 2018-12-07 11:00

Author(s): A. Barış Özgüler, Robert Joynt, and Maxim G. Vavilov

A general time-dependent quantum system can be driven fast from its initial ground state to its final ground state without generating transitions by adding a steering term to the Hamiltonian. We show how this technique can be modified to improve on the standard quantum adiabatic algorithm by making ...


[Phys. Rev. A 98, 062311] Published Fri Dec 07, 2018

Categories: Journals, Physics

Locally optimal control of continuous-variable entanglement

Fri, 2018-12-07 11:00

Author(s): Francesco Albarelli, Uther Shackerley-Bennett, and Alessio Serafini

We consider a system of two bosonic modes each subject to the dynamics induced by a thermal Markovian environment and we identify instantaneous, local symplectic controls that minimize the loss of entanglement in the Gaussian regime. By minimizing the decrease of the logarithmic negativity at every ...


[Phys. Rev. A 98, 062312] Published Fri Dec 07, 2018

Categories: Journals, Physics

Self-testing quantum states and measurements in the prepare-and-measure scenario

Thu, 2018-12-06 11:00

Author(s): Armin Tavakoli, Jędrzej Kaniewski, Tamás Vértesi, Denis Rosset, and Nicolas Brunner

The goal of self-testing is to characterize an a priori unknown quantum system based solely on measurement statistics, i.e., using an uncharacterized measurement device. Here we develop self-testing methods for quantum prepare-and-measure experiments, thus not necessarily relying on entanglement and...


[Phys. Rev. A 98, 062307] Published Thu Dec 06, 2018

Categories: Journals, Physics

Complementary-multiphase quantum search for all numbers of target items

Thu, 2018-12-06 11:00

Author(s): Tan Li, Wan-Su Bao, He-Liang Huang, Feng-Guang Li, Xiang-Qun Fu, Shuo Zhang, Chu Guo, Yu-Tao Du, Xiang Wang, and Jie Lin

Grover's algorithm achieves a quadratic speedup over classical algorithms, but it is considered necessary to know the value of λ exactly [Phys. Rev. Lett. 95, 150501 (2005); Phys. Rev. Lett. 113, 210501 (2014)], where λ is the fraction of target items in the database. In this paper, we find out that...


[Phys. Rev. A 98, 062308] Published Thu Dec 06, 2018

Categories: Journals, Physics

Enhancing the efficiency of quantum annealing via reinforcement: A path-integral Monte Carlo simulation of the quantum reinforcement algorithm

Thu, 2018-12-06 11:00

Author(s): A. Ramezanpour

The standard quantum annealing algorithm tries to approach the ground state of a classical system by slowly decreasing the hopping rates of a quantum random walk in the configuration space of the problem, where the on-site energies are provided by the classical energy function. In a quantum reinforc...


[Phys. Rev. A 98, 062309] Published Thu Dec 06, 2018

Categories: Journals, Physics

Quantum communication improved by spectral entanglement and supplementary chromatic dispersion

Thu, 2018-12-06 11:00

Author(s): Mikołaj Lasota and Piotr Kolenderski

Implementations of many quantum communication protocols require sources of photon pairs. However, optimization of the properties of these photons for specific applications is an open problem. We theoretically demonstrate the possibility of extending the maximal distance of secure quantum communicati...


[Phys. Rev. A 98, 062310] Published Thu Dec 06, 2018

Categories: Journals, Physics

Masking quantum information in multipartite scenario

Wed, 2018-12-05 11:00

Author(s): Mao-Sheng Li and Yan-Ling Wang

Recently, Modi et al. [Phys. Rev. Lett. 120, 230501 (2018)] found that masking quantum information is impossible in a bipartite scenario. This adds another item to the no-go theorems. In this paper, we present some schemes different from error correction codes, which show that quantum states can be ...


[Phys. Rev. A 98, 062306] Published Wed Dec 05, 2018

Categories: Journals, Physics

Device-independent witness of arbitrary-dimensional quantum systems employing binary-outcome measurements

Tue, 2018-12-04 11:00

Author(s): Mikołaj Czechlewski, Debashis Saha, Armin Tavakoli, and Marcin Pawłowski

Device-independent dimension witnesses (DWs) are a remarkable way to test the dimension of a quantum system in a prepare-and-measure scenario imposing minimal assumptions on the internal features of the devices. However, as the dimension increases, the major obstacle in the realization of DWs arises...


[Phys. Rev. A 98, 062305] Published Tue Dec 04, 2018

Categories: Journals, Physics

High-dimensional measurement-device-independent quantum key distribution on two-dimensional subspaces

Mon, 2018-12-03 11:00

Author(s): Luca Dellantonio, Anders S. Sørensen, and Davide Bacco

Quantum key distribution (QKD) provides ultimate cryptographic security based on the laws of quantum mechanics. For point-to-point QKD protocols, the security of the generated key is compromised by detector side channel attacks. This problem can be solved with measurement-device-independent QKD (mdi...


[Phys. Rev. A 98, 062301] Published Mon Dec 03, 2018

Categories: Journals, Physics

Decoding schemes for foliated sparse quantum error-correcting codes

Mon, 2018-12-03 11:00

Author(s): A. Bolt, D. Poulin, and T. M. Stace

Foliated quantum codes are a resource for fault-tolerant measurement-based quantum error correction for quantum repeaters and for quantum computation. They represent a general approach to integrating a range of possible quantum error correcting codes into larger fault-tolerant networks. Here, we pre...


[Phys. Rev. A 98, 062302] Published Mon Dec 03, 2018

Categories: Journals, Physics

Selective and efficient quantum process tomography in arbitrary finite dimension

Mon, 2018-12-03 11:00

Author(s): Ignacio Perito, Augusto J. Roncaglia, and Ariel Bendersky

The characterization of quantum processes is a key tool in quantum information processing tasks for several reasons: on one hand, it allows one to acknowledge errors in the implementations of quantum algorithms; on the other, it allows one to characterize unknown processes occurring in nature. Bende...


[Phys. Rev. A 98, 062303] Published Mon Dec 03, 2018

Categories: Journals, Physics

Witnessing bipartite entanglement sequentially by multiple observers

Mon, 2018-12-03 11:00

Author(s): Anindita Bera, Shiladitya Mal, Aditi Sen(De), and Ujjwal Sen

We investigate sharing of bipartite entanglement in a scenario where half of an entangled pair is possessed and projectively measured by one observer, called Alice, while the other half is subjected to measurements performed sequentially, independently, and unsharply, by multiple observers, called B...


[Phys. Rev. A 98, 062304] Published Mon Dec 03, 2018

Categories: Journals, Physics

Alternative method for deriving nonlocal multipartite product states

Thu, 2018-11-29 11:00

Author(s): Mao-Sheng Li and Yan-Ling Wang

We can only perform finite rounds of measurements in protocols with local operations and classical communication (LOCC). In this paper, we propose a set of product states that require infinite rounds of measurements in order to distinguish this given set of states perfectly by LOCC. Therefore, we ca...


[Phys. Rev. A 98, 052352] Published Thu Nov 29, 2018

Categories: Journals, Physics

Gaussian channels that are eventually entanglement breaking yet asymptotically nonclassicality saving

Thu, 2018-11-29 11:00

Author(s): Sagnik Garai and J. Solomon Ivan

A complete classification of single-mode bosonic Gaussian channels on the basis of being quantum-limited or entanglement breaking under n-fold composition is obtained. Parametric forms for all single-mode bosonic Gaussian channels that remain quantum-limited under n-fold composition is obtained. It ...


[Phys. Rev. A 98, 052353] Published Thu Nov 29, 2018

Categories: Journals, Physics

Bloch-Siegert shift in a hybrid quantum register: Quantification and compensation

Thu, 2018-11-29 11:00

Author(s): Jingfu Zhang, Sagnik Saha, and Dieter Suter

Quantum information processing relies on unitary transformations applied to specific qubits. In most cases, these gate operations are driven by alternating electromagnetic fields that are near resonant with specific transitions between eigenstates of the system Hamiltonian. For single-qubit gate ope...


[Phys. Rev. A 98, 052354] Published Thu Nov 29, 2018

Categories: Journals, Physics

Testing quantum fault tolerance on small systems

Wed, 2018-11-28 11:00

Author(s): D. Willsch, M. Willsch, F. Jin, H. De Raedt, and K. Michielsen

We extensively test a recent protocol to demonstrate quantum fault tolerance on three systems: (1) a real-time simulation of five spin qubits coupled to an environment with two-level defects, (2) a real-time simulation of transmon quantum computers, and (3) the 16-qubit processor of the IBM Q Experi...


[Phys. Rev. A 98, 052348] Published Wed Nov 28, 2018

Categories: Journals, Physics

Resource theory of quantum non-Gaussianity and Wigner negativity

Wed, 2018-11-28 11:00

Author(s): Francesco Albarelli, Marco G. Genoni, Matteo G. A. Paris, and Alessandro Ferraro

We develop a resource theory for continuous-variable systems grounded on operations routinely available within current quantum technologies. In particular, the set of free operations is convex and includes quadratic transformations and conditional coarse-grained measurements. The present theory lend...


[Phys. Rev. A 98, 052350] Published Wed Nov 28, 2018

Categories: Journals, Physics

Entanglement activation from quantum coherence and superposition

Wed, 2018-11-28 11:00

Author(s): Lu-Feng Qiao, Alexander Streltsov, Jun Gao, Swapan Rana, Ruo-Jing Ren, Zhi-Qiang Jiao, Cheng-Qiu Hu, Xiao-Yun Xu, Ci-Yu Wang, Hao Tang, Ai-Lin Yang, Zhi-Hao Ma, Maciej Lewenstein, and Xian-Min Jin

Quantum entanglement and coherence are two fundamental features of nature, arising from the superposition principle of quantum mechanics. While considered as puzzling phenomena in the early days of quantum theory, it is only very recently that entanglement and coherence have been recognized as resou...


[Phys. Rev. A 98, 052351] Published Wed Nov 28, 2018

Categories: Journals, Physics