PRA: Quantum information

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Recently published articles in Phys. Rev. A in the Table of Content section "Quantum information"
Updated: 25 min 7 sec ago

Nonstandard protocols for joint remote preparation of a general quantum state and hybrid entanglement of any dimension

5 hours 59 min ago

Author(s): Nguyen Ba An, Le Thanh Dat, and Jaewan Kim

Joint remote state preparation (JRSP) is a useful way to securely transfer quantum information encoded in quantum states between distant places without physically sending the states themselves. In this paper we study JRSP of the most general D-dimensional quantum state called quDit state, with arbit...

[Phys. Rev. A 98, 042329] Published Mon Oct 22, 2018

Categories: Journals, Physics

Tuning the coupling between superconducting resonators with collective qubits

Fri, 2018-10-19 12:00

Author(s): Qi-Ming Chen, Yu-xi Liu, Luyan Sun, and Re-Bing Wu

By coupling a collection of two-level artificial atoms simultaneously to two superconducting resonators, we propose a quantum switch that can tune the resonator-resonator coupling strength from zero to a large value proportional to the qubit number. This process is realized by preparing the qubits i...

[Phys. Rev. A 98, 042328] Published Fri Oct 19, 2018

Categories: Journals, Physics

Quantum annealing of the $p$-spin model under inhomogeneous transverse field driving

Thu, 2018-10-18 12:00

Author(s): Yuki Susa, Yu Yamashiro, Masayuki Yamamoto, Itay Hen, Daniel A. Lidar, and Hidetoshi Nishimori

We solve the mean-field-like p-spin Ising model under a spatiotemporal inhomogeneous transverse field to study the effects of inhomogeneity on the performance of quantum annealing. We previously found that the problematic first-order quantum phase transition that arises under the conventional homoge...

[Phys. Rev. A 98, 042326] Published Thu Oct 18, 2018

Categories: Journals, Physics

Entanglement of two noninteracting qubits via a mesoscopic system

Thu, 2018-10-18 12:00

Author(s): Maryam Sadat Mirkamali, David G. Cory, and Joseph Emerson

We propose a method for entangling two noninteracting qubits by measuring their parity indirectly through an intermediate mesoscopic system. The protocol is designed to require only global control and course-grained collective measurement of the mesoscopic system along with local interactions betwee...

[Phys. Rev. A 98, 042327] Published Thu Oct 18, 2018

Categories: Journals, Physics

Dissipative quantum entanglement dynamics of two and three qubits due to the dynamical Lamb effect

Thu, 2018-10-18 12:00

Author(s): Mirko Amico, Oleg L. Berman, and Roman Ya. Kezerashvili

A theoretical framework to investigate the time evolution of the quantum entanglement due to the dynamical Lamb effect between two and three superconducting qubits coupled to a coplanar waveguide in the presence of different sources of dissipation is developed. Guidelines on how to proceed in the N-...

[Phys. Rev. A 98, 042325] Published Thu Oct 18, 2018

Categories: Journals, Physics

Secure quantum communication in the presence of phase- and polarization-dependent loss

Wed, 2018-10-17 12:00

Author(s): Chenyang Li, Marcos Curty, Feihu Xu, Olinka Bedroya, and Hoi-Kwong Lo

Silicon photonics holds the promise of the miniaturization of quantum communication devices. Recently, silicon chip optical transmitters for quantum key distribution (QKD) have been built and demonstrated experimentally. Nonetheless, these silicon chips suffer substantial phase- and polarization-dep...

[Phys. Rev. A 98, 042324] Published Wed Oct 17, 2018

Categories: Journals, Physics

Ancilla-assisted linear optical Bell measurements and their optimality

Tue, 2018-10-16 12:00

Author(s): Andrea Olivo and Frédéric Grosshans

In the last decade Grice [Phys. Rev. A 84, 042331 (2011)] and Ewert and van Loock [Phys. Rev. Lett. 113, 140403 (2014)] found linear optical networks achieving near-unit efficiency unambiguous Bell state discrimination, when fed with increasingly complex ancillary states. However, except for the vac...

[Phys. Rev. A 98, 042323] Published Tue Oct 16, 2018

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Secret key rate of a continuous-variable quantum-key-distribution scheme when the detection process is inaccessible to eavesdroppers

Mon, 2018-10-15 12:00

Author(s): Ryo Namiki, Akira Kitagawa, and Takuya Hirano

We have developed a method to calculate a secret key rate of a continuous-variable quantum-key-distribution scheme using four coherent states and postselection for a general model of Gaussian attacks. We assume that the transmission line and detection process are described by a pair of Gaussian chan...

[Phys. Rev. A 98, 042319] Published Mon Oct 15, 2018

Categories: Journals, Physics

Experimentally detecting a quantum change point via the Bayesian inference

Mon, 2018-10-15 12:00

Author(s): Shang Yu, Chang-Jiang Huang, Jian-Shun Tang, Zhih-Ahn Jia, Yi-Tao Wang, Zhi-Jin Ke, Wei Liu, Xiao Liu, Zong-Quan Zhou, Ze-Di Cheng, Jin-Shi Xu, Yu-Chun Wu, Yuan-Yuan Zhao, Guo-Yong Xiang, Chuan-Feng Li, Guang-Can Guo, Gael Sentís, and Ramon Muñoz-Tapia

Detecting a change point is a crucial task in statistics that has been recently extended to the quantum realm. A source state generator that emits a series of single photons in a default state suffers an alteration at some point and starts to emit photons in a mutated state. The problem consists in ...

[Phys. Rev. A 98, 040301(R)] Published Mon Oct 15, 2018

Categories: Journals, Physics

Randomness quantification of coherent detection

Mon, 2018-10-15 12:00

Author(s): Hongyi Zhou, Pei Zeng, Mohsen Razavi, and Xiongfeng Ma

Continuous-variable quantum cryptographic systems, including random number generation and key distribution, are often based on coherent detection. The essence of the security analysis lies in the randomness quantification. Previous analyses employ a semiquantum picture, where the strong local oscill...

[Phys. Rev. A 98, 042321] Published Mon Oct 15, 2018

Categories: Journals, Physics

Deconstruction and conditional erasure of quantum correlations

Mon, 2018-10-15 12:00

Author(s): Mario Berta, Fernando G. S. L. Brandão, Christian Majenz, and Mark M. Wilde

We define the deconstruction cost of a tripartite quantum state on systems ABE as the minimum rate of noise needed to apply to the AE systems, such that there is negligible disturbance to the marginal state on the BE systems, while the system A of the resulting state is locally recoverable from the ...

[Phys. Rev. A 98, 042320] Published Mon Oct 15, 2018

Categories: Journals, Physics

Preservation of quantum nonbilocal correlations in noisy entanglement-swapping experiments using weak measurements

Mon, 2018-10-15 12:00

Author(s): Shashank Gupta, Shounak Datta, and A. S. Majumdar

A tripartite quantum network is said to be bilocal if two independent sources produce a pair of bipartite entangled states. Quantum nonbilocal correlation emerges when the central party which possesses two particles from two different sources performs Bell-state measurement on them and nonlocality i...

[Phys. Rev. A 98, 042322] Published Mon Oct 15, 2018

Categories: Journals, Physics

Uhlmann fidelities from tensor networks

Fri, 2018-10-12 12:00

Author(s): Markus Hauru and Guifre Vidal

Given two states |ψ〉 and |ϕ〉 of a quantum many-body system, one may use the overlap or fidelity |〈ψ|ϕ〉| to quantify how similar they are. To further resolve the similarity of |ψ〉 and |ϕ〉 in space, one can consider their reduced density matrices ρ and σ on various regions of the system and compute th...

[Phys. Rev. A 98, 042316] Published Fri Oct 12, 2018

Categories: Journals, Physics

Nonlocality of all quantum networks

Fri, 2018-10-12 12:00

Author(s): Ming-Xing Luo

The multipartite correlations derived from local measurements on some composite quantum systems are inconsistent with those reproduced classically. This inconsistency is known as the quantum nonlocality and shows a milestone in the foundations of quantum theory. Still, it is NP hard to decide a nonl...

[Phys. Rev. A 98, 042317] Published Fri Oct 12, 2018

Categories: Journals, Physics

Joint quantum-state and measurement tomography with incomplete measurements

Fri, 2018-10-12 12:00

Author(s): Adam C. Keith, Charles H. Baldwin, Scott Glancy, and E. Knill

Estimation of quantum states and measurements is crucial for the implementation of quantum information protocols. The standard method for each is quantum tomography. However, quantum tomography suffers from systematic errors caused by imperfect knowledge of the system. We present a procedure to simu...

[Phys. Rev. A 98, 042318] Published Fri Oct 12, 2018

Categories: Journals, Physics

Measurement-based adaptation protocol with quantum reinforcement learning

Thu, 2018-10-11 12:00

Author(s): F. Albarrán-Arriagada, J. C. Retamal, E. Solano, and L. Lamata

Machine learning employs dynamical algorithms that mimic the human capacity to learn, where the reinforcement learning ones are among the most similar to humans in this respect. On the other hand, adaptability is an essential aspect to perform any task efficiently in a changing environment, and it i...

[Phys. Rev. A 98, 042315] Published Thu Oct 11, 2018

Categories: Journals, Physics

Non-Gaussianity and entropy-bounded uncertainty relations: Application to detection of non-Gaussian entangled states

Wed, 2018-10-10 12:00

Author(s): Kyunghyun Baek and Hyunchul Nha

We suggest an improved version of the Robertson–Schrödinger uncertainty relation for canonically conjugate variables by taking into account a pair of characteristics of states: non-Gaussianity and mixedness quantified by using fidelity and entropy, respectively. This relation is saturated by both Ga...

[Phys. Rev. A 98, 042314] Published Wed Oct 10, 2018

Categories: Journals, Physics

Sharing of nonlocal advantage of quantum coherence by sequential observers

Tue, 2018-10-09 12:00

Author(s): Shounak Datta and A. S. Majumdar

Nonlocal advantage of quantum coherence (NAQC) or steerability of local quantum coherence is a strong nonlocal resource based on coherence complementarity relations. In this work, we provide an upper bound on the number of observers who can independently steer the coherence of the observer in the ot...

[Phys. Rev. A 98, 042311] Published Tue Oct 09, 2018

Categories: Journals, Physics

Digital quantum computation of fermion-boson interacting systems

Tue, 2018-10-09 12:00

Author(s): Alexandru Macridin, Panagiotis Spentzouris, James Amundson, and Roni Harnik

We introduce a method for representing the low-energy subspace of a bosonic field theory on the qubit space of digital quantum computers. This discretization leads to an exponentially precise description of the subspace of the continuous theory thanks to the Nyquist-Shannon sampling theorem. The met...

[Phys. Rev. A 98, 042312] Published Tue Oct 09, 2018

Categories: Journals, Physics

Quantumness of quantum channels

Tue, 2018-10-09 12:00

Author(s): Fereshte Shahbeigi and Seyed Javad Akhtarshenas

Quantum coherence is a fundamental aspect of quantum physics and plays a central role in quantum information science. This essential property of the quantum states could be fragile under the influence of the quantum operations. The extent to which quantum coherence is diminished depends both on the ...

[Phys. Rev. A 98, 042313] Published Tue Oct 09, 2018

Categories: Journals, Physics