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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Experimental distillation of bipartite polarization entanglement using polarizing Mach-Zehnder interferometers

Mon, 2018-08-13 12:00

Author(s): Chithrabhanu Perumangatt, Tang Zong Sheng, and Alexander Ling

Entanglement distillation is the process of concentrating entanglement from a given quantum state. We present a technique for distillation of bipartite polarization entanglement using interferometry. This technique can be optimized to extract maximal entanglement from any pure or mixed entangled sta...

[Phys. Rev. A 98, 022313] Published Mon Aug 13, 2018

Categories: Journals, Physics

Error reduction in quantum annealing using boundary cancellation: Only the end matters

Mon, 2018-08-13 12:00

Author(s): Lorenzo Campos Venuti and Daniel A. Lidar

The adiabatic theorem of quantum mechanics states that the error between an instantaneous eigenstate of a time-dependent Hamiltonian and the state given by quantum evolution of duration τ is upper bounded by C/τ for some positive constant C. It has been known for decades that this error can be reduc...

[Phys. Rev. A 98, 022315] Published Mon Aug 13, 2018

Categories: Journals, Physics

Reverse annealing for the fully connected $p$-spin model

Mon, 2018-08-13 12:00

Author(s): Masaki Ohkuwa, Hidetoshi Nishimori, and Daniel A. Lidar

Reverse annealing is a variant of quantum annealing that starts from a given classical configuration of spins (qubits). In contrast to the conventional formulation, where one starts from a uniform superposition of all possible states (classical configurations), quantum fluctuations are first increas...

[Phys. Rev. A 98, 022314] Published Mon Aug 13, 2018

Categories: Journals, Physics

Environment-assisted analog quantum search

Mon, 2018-08-13 12:00

Author(s): Leonardo Novo, Shantanav Chakraborty, Masoud Mohseni, and Yasser Omar

Two main obstacles for observing quantum advantage in noisy intermediate-scale quantum computers (NISQ) are the finite-precision effects due to control errors, or disorders, and decoherence effects due to thermal fluctuations. It has been shown that dissipative quantum computation is possible in the...

[Phys. Rev. A 98, 022316] Published Mon Aug 13, 2018

Categories: Journals, Physics

Enhanced entanglement criterion via symmetric informationally complete measurements

Fri, 2018-08-10 12:00

Author(s): Jiangwei Shang, Ali Asadian, Huangjun Zhu, and Otfried Gühne

The challenges of entanglement detection lead to the development of several entanglement measures and criteria. Here a special type of measurement is used to attest entanglement in a stronger way, i.e. it catches forms that are missed by other criteria and is effective in a single-shot fashion.

[Phys. Rev. A 98, 022309] Published Fri Aug 10, 2018

Categories: Journals, Physics

One-sided device-independent self-testing of any pure two-qubit entangled state

Fri, 2018-08-10 12:00

Author(s): Suchetana Goswami, Bihalan Bhattacharya, Debarshi Das, Souradeep Sasmal, C. Jebaratnam, and A. S. Majumdar

We consider the problem of one-sided device-independent self-testing of any pure entangled two-qubit state based on steering inequalities which certify the presence of quantum steering. In particular, we note that in the 2-2-2 steering scenario (involving two parties, two measurement settings per pa...

[Phys. Rev. A 98, 022311] Published Fri Aug 10, 2018

Categories: Journals, Physics

Nonlocal advantage of quantum coherence in high-dimensional states

Fri, 2018-08-10 12:00

Author(s): Ming-Liang Hu and Heng Fan

By local measurements on party A of a system AB and classical communication between its two parties, one can achieve a nonlocal advantage of quantum coherence (NAQC) on party B. For the l1 norm of coherence and the relative entropy of coherence, we generalized the framework of NAQC for two qubits an...

[Phys. Rev. A 98, 022312] Published Fri Aug 10, 2018

Categories: Journals, Physics

Decentralized base-graph routing for the quantum internet

Fri, 2018-08-10 12:00

Author(s): Laszlo Gyongyosi and Sandor Imre

Quantum repeater networks are a fundamental of any future quantum internet and long-distance quantum communications. The entangled quantum nodes can communicate through several different levels of entanglement, leading to a heterogeneous, multilevel network structure. The level of entanglement betwe...

[Phys. Rev. A 98, 022310] Published Fri Aug 10, 2018

Categories: Journals, Physics

Unruh effect as a noisy quantum channel

Wed, 2018-08-08 12:00

Author(s): Doyeol Ahn

We studied the change of the nonlocal correlation of the entanglement in Rindler space-time by showing that the Unruh effect can be interpreted as a noisy quantum channel having a complete positive and trace preserving map with an “operator sum representation.” It is shown that the entanglement fide...

[Phys. Rev. A 98, 022308] Published Wed Aug 08, 2018

Categories: Journals, Physics

Open-system quantum error correction

Tue, 2018-08-07 12:00

Author(s): Yink Loong Len and Hui Khoon Ng

We study the performance of quantum error correction (QEC) on a system undergoing open-system (OS) dynamics. The noise on the system originates from a joint quantum channel on the system-bath composite, a framework that includes and interpolates between the commonly used system-only quantum noise ch...

[Phys. Rev. A 98, 022307] Published Tue Aug 07, 2018

Categories: Journals, Physics

Robust readout of bosonic qubits in the dispersive coupling regime

Mon, 2018-08-06 12:00

Author(s): Connor T. Hann, Salvatore S. Elder, Christopher S. Wang, Kevin Chou, Robert J. Schoelkopf, and Liang Jiang

High-fidelity qubit measurements play a crucial role in quantum computation, communication, and metrology. In recent experiments, it has been shown that readout fidelity can be improved by performing repeated quantum nondemolition (QND) readouts of a qubit's state through an ancilla. For a qubit enc...

[Phys. Rev. A 98, 022305] Published Mon Aug 06, 2018

Categories: Journals, Physics

Interrelation between partial coherence and quantum correlations

Mon, 2018-08-06 12:00

Author(s): Sunho Kim, Longsuo Li, Asutosh Kumar, and Junde Wu

Both coherence and entanglement stem from the superposition principle, capture quantumness of a physical system, and play a central role in quantum physics. In a multipartite quantum system, coherence and quantum correlations are closely connected. In particular, it has been established that quantum...

[Phys. Rev. A 98, 022306] Published Mon Aug 06, 2018

Categories: Journals, Physics

Several nonlocal sets of multipartite pure orthogonal product states

Fri, 2018-08-03 12:00

Author(s): Saronath Halder

It is known that there exist sets of pure orthogonal product states which cannot be perfectly distinguished by local operations and classical communication (LOCC). Such sets are nonlocal sets which exhibit nonlocality without entanglement. These nonlocal sets can be completable or uncompletable. In ...

[Phys. Rev. A 98, 022303] Published Fri Aug 03, 2018

Categories: Journals, Physics

Local unitary classification for sets of generalized Bell states

Fri, 2018-08-03 12:00

Author(s): Bujiao Wu, Jiaqing Jiang, Jialin Zhang, Guojing Tian, and Xiaoming Sun

In this paper, we study the local unitary (LU) classification for pairs (triples) of generalized Bell states, based on the local unitary equivalence of two sets. In detail, we first introduce some general unitary operators which give us more local unitary equivalent sets besides Clifford operators. ...

[Phys. Rev. A 98, 022304] Published Fri Aug 03, 2018

Categories: Journals, Physics

Specification format and a verification method of fault-tolerant quantum circuits

Thu, 2018-08-02 12:00

Author(s): Alexandru Paler and Simon J. Devitt

Quantum computations are expressed in general as quantum circuits, which are specified by ordered lists of quantum gates. The resulting specifications are used during the optimization and execution of the expressed computations. However, the specification format makes it difficult to verify that opt...

[Phys. Rev. A 98, 022302] Published Thu Aug 02, 2018

Categories: Journals, Physics

Constrained quantum annealing of graph coloring

Wed, 2018-08-01 12:00

Author(s): Kazue Kudo

We investigate a quantum annealing approach based on real-time quantum dynamics for graph coloring. In this approach, a driving Hamiltonian is chosen so that constraints are naturally satisfied without penalty terms and the dimension of the Hilbert space is considerably reduced. The total Hamiltonia...

[Phys. Rev. A 98, 022301] Published Wed Aug 01, 2018

Categories: Journals, Physics

Dual correspondence between classical spin models and quantum Calderbank-Shor-Steane states

Tue, 2018-07-31 12:00

Author(s): Mohammad Hossein Zarei and Afshin Montakhab

The correspondence between classical spin models and quantum states has attracted much attention in recent years. However, it remains an open problem as to which specific spin model a given (well-known) quantum state maps. Here, we provide such an explicit correspondence for an important class of qu...

[Phys. Rev. A 98, 012337] Published Tue Jul 31, 2018

Categories: Journals, Physics

Adaptive quantum tomography in high dimensions

Tue, 2018-07-31 12:00

Author(s): L. Pereira, L. Zambrano, J. Cortés-Vega, S. Niklitschek, and A. Delgado

Standard quantum tomography of a single qudit achieves an infidelity that scales in the worst case as O(1/N) for a sample of size N. Here, we propose a suitable generalization of the two-stage adaptive quantum tomography for a qubit to the case of a single qudit. This achieves an infidelity of the o...

[Phys. Rev. A 98, 012339] Published Tue Jul 31, 2018

Categories: Journals, Physics

Fault-tolerant fermionic quantum computation based on color code

Tue, 2018-07-31 12:00

Author(s): Ying Li

An important approach to fault-tolerant quantum computation is protecting logical information using quantum error correction. Usually, logical information is in the form of logical qubits, which are encoded in physical qubits using quantum error correction codes. Compared with qubit quantum computat...

[Phys. Rev. A 98, 012336] Published Tue Jul 31, 2018

Categories: Journals, Physics

Quantum walk search on Kronecker graphs

Tue, 2018-07-31 12:00

Author(s): Thomas G. Wong, Konstantin Wünscher, Joshua Lockhart, and Simone Severini

Kronecker graphs, obtained by repeatedly performing the Kronecker product of the adjacency matrix of an “initiator” graph with itself, have risen in popularity in network science due to their ability to generate complex networks with real-world properties. We explore spatial search by continuous-tim...

[Phys. Rev. A 98, 012338] Published Tue Jul 31, 2018

Categories: Journals, Physics