PRA: Quantum information

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Recently published articles in Phys. Rev. A in the Table of Content section "Quantum information"
Updated: 7 min 6 sec ago

Quantifying the performance of approximate teleportation and quantum error correction via symmetric 2-PPT-extendible channels

Thu, 2023-01-26 11:00

Author(s): Tharon Holdsworth, Vishal Singh, and Mark M. Wilde

The ideal realization of quantum teleportation relies on having access to a maximally entangled state; however, in practice, such an ideal state is typically not available and one can instead only realize an approximate teleportation. With this in mind, we present a method to quantify the performanc…

[Phys. Rev. A 107, 012428] Published Thu Jan 26, 2023

Categories: Journals, Physics

Experimental violation of the Leggett-Garg inequality in a three-level trapped-ion system

Wed, 2023-01-25 11:00

Author(s): Tianxiang Zhan, Chunwang Wu, Manchao Zhang, Qingqing Qin, Xueying Yang, Han Hu, Wenbo Su, Jie Zhang, Ting Chen, Yi Xie, Wei Wu, and Pingxing Chen

Leggett-Garg inequality (LGI) is used to detect whether the macroscopic superposition state exists. Classical systems obey the LGI, but quantum systems may violate it. In the multilevel system, different state update rules determine different upper bounds of LGI. In this work, we experimentally test…

[Phys. Rev. A 107, 012424] Published Wed Jan 25, 2023

Categories: Journals, Physics

Exponential data encoding for quantum supervised learning

Mon, 2023-01-23 11:00

Author(s): S. Shin, Y. S. Teo, and H. Jeong

Reliable quantum supervised learning of a multivariate function mapping depends on the expressivity of the corresponding quantum circuit and measurement resources. We introduce exponential-data-encoding strategies that are hardware-efficient and optimal among all nonentangling Pauli-encoded schemes,…

[Phys. Rev. A 107, 012422] Published Mon Jan 23, 2023

Categories: Journals, Physics

Thermal devices powered by generalized measurements with indefinite causal order

Mon, 2023-01-23 11:00

Author(s): Pedro R. Dieguez, Vinicius F. Lisboa, and Roberto M. Serra

A quantum-controlled device may produce a scenario in which two general quantum operations can be performed in such a way that it is not possible to associate a definite order for the operation's application. Such an indefinite causal order can be explored to produce nontrivial effects in quantum th…

[Phys. Rev. A 107, 012423] Published Mon Jan 23, 2023

Categories: Journals, Physics

Experimental detection of quantum steerability based on the critical radius in an all-optical system

Fri, 2023-01-20 11:00

Author(s): Xiao-Gang Fan, Fa Zhao, Huan Yang, Zhi-Yong Ding, Dong Wang, and Liu Ye

Quantum steering is the ability that one system affects another one without delay by performing local measurements. During the past few years, the research on quantum steering has been verified in a number of experiments by the choices of measurements. But this research cannot detect all steerable s…

[Phys. Rev. A 107, 012419] Published Fri Jan 20, 2023

Categories: Journals, Physics

Continuous simultaneous measurement of position and momentum of a particle

Fri, 2023-01-20 11:00

Author(s): Filip Gampel and Mariusz Gajda

We formulate a model of a quantum particle continuously monitored by detectors measuring simultaneously its position and momentum. We implement the postulate of wave-function collapse by assuming that upon detection the particle is found in one of the meters' states chosen as a discrete subset of co…

[Phys. Rev. A 107, 012420] Published Fri Jan 20, 2023

Categories: Journals, Physics

Partition-function estimation: Quantum and quantum-inspired algorithms

Fri, 2023-01-20 11:00

Author(s): Andrew Jackson, Theodoros Kapourniotis, and Animesh Datta

We present two algorithms, one quantum and one classical, for estimating partition functions of quantum spin Hamiltonians. The first is a DQC1 (deterministic quantum computation with one clean qubit) algorithm. The second, for real temperatures, achieves performance comparable to a state-of-the-art …

[Phys. Rev. A 107, 012421] Published Fri Jan 20, 2023

Categories: Journals, Physics

Success probability and performance optimization in non-Gaussian continuous-variable quantum teleportation

Tue, 2023-01-17 11:00

Author(s): Chandan Kumar and Shikhar Arora

Non-Gaussian operations have been shown to enhance the fidelity of continuous-variable quantum teleportation. However, a disadvantage of these non-Gaussian operations is that they are probabilistic in nature. In this article we study the trade-off between teleportation fidelity and success probabili…

[Phys. Rev. A 107, 012418] Published Tue Jan 17, 2023

Categories: Journals, Physics

Entanglement of mechanical modes in a doubly resonant optomechanical cavity of a correlated emission laser

Fri, 2023-01-13 11:00

Author(s): Mekonnen Bekele, Tewodros Yirgashewa, and Sintayehu Tesfa

We explore the extent of the induced entanglement of the mechanical modes that can be attributed to the transfer of coherence from two-mode cavity radiation in a doubly resonant optomechanical cavity. It is expected that this scheme can support a generation of mechanical oscillations with a robust d…

[Phys. Rev. A 107, 012417] Published Fri Jan 13, 2023

Categories: Journals, Physics

Entanglement structures in quantum field theories: Negativity cores and bound entanglement in the vacuum

Wed, 2023-01-11 11:00

Author(s): Natalie Klco, D. H. Beck, and Martin J. Savage

The many-body entanglement between two finite (size-d) disjoint vacuum regions of noninteracting lattice scalar field theory in one spatial dimension, i.e., a (dA×dB)mixed Gaussian continuous variable system, is locally transformed into a tensor-product core of (1A×1B)mixed entangled pairs. Accessib…

[Phys. Rev. A 107, 012415] Published Wed Jan 11, 2023

Categories: Journals, Physics

Calculating the ground-state energy of benzene under spatial deformations with noisy quantum computing

Wed, 2023-01-11 11:00

Author(s): Wassil Sennane, Jean-Philip Piquemal, and Marko J. Rančić

In this paper we calculate the ground-state energy of benzene under spatial deformations by using the variational quantum eigensolver. The primary goal of the study is to estimate the feasibility of using quantum computing Ansätze on near-term devices to solve problems with a large number of orbital…

[Phys. Rev. A 107, 012416] Published Wed Jan 11, 2023

Categories: Journals, Physics

Direct measurement of quantum Fisher information

Tue, 2023-01-10 11:00

Author(s): Xingyu Zhang, Xiao-Ming Lu, Jing Liu, Wenkui Ding, and Xiaoguang Wang

In the adiabatic perturbation theory, Berry curvature is related to the generalized force, and the quantum metric tensor is linked with energy fluctuation. While the former is tested with numerous numerical results and experimental realizations, the latter is less considered. Quantum Fisher informat…

[Phys. Rev. A 107, 012414] Published Tue Jan 10, 2023

Categories: Journals, Physics

Problem-size-independent angles for a Grover-driven quantum approximate optimization algorithm

Mon, 2023-01-09 11:00

Author(s): David Headley and Frank K. Wilhelm

The quantum approximate optimization algorithm (QAOA) requires that circuit parameters are determined that allow one to sample from high-quality solutions to combinatorial optimization problems. Such parameters can be obtained using either costly outer-loop optimization procedures and repeated calls…

[Phys. Rev. A 107, 012412] Published Mon Jan 09, 2023

Categories: Journals, Physics

Entanglement transition through Hilbert-space localization

Mon, 2023-01-09 11:00

Author(s): Quancheng Liu and Klaus Ziegler

We study Hilbert-space localization of the many-body dynamics due to ergodicity breaking and analyze this effect in terms of the entanglement entropy and the entanglement spectrum. We find a transition from a regime driven by quantum tunneling to a regime that is dominated by boson-boson interaction…

[Phys. Rev. A 107, 012413] Published Mon Jan 09, 2023

Categories: Journals, Physics

Entanglement measures based on the complete information of reduced states

Fri, 2023-01-06 11:00

Author(s): Zhi-Xiang Jin, Xianqing Li-Jost, Shao-Ming Fei, and Cong-Feng Qiao

Quantum entanglement has been verified experimentally and applied in quantum computing, quantum sensing, and quantum networks. It is of great significance to find measures to characterize the quantum entanglement faithfully. In this work, by exploiting the Schmidt decomposition of bipartite states, …

[Phys. Rev. A 107, 012409] Published Fri Jan 06, 2023

Categories: Journals, Physics

Generation of long-lived $W$ states via reservoir engineering in dissipatively coupled systems

Fri, 2023-01-06 11:00

Author(s): Guo-Qiang Zhang, Wei Feng, Wei Xiong, Qi-Ping Su, and Chui-Ping Yang

Very recently, dissipative coupling was discovered, which develops and broadens methods for controlling and utilizing light-matter interactions. Here, we propose a scheme to generate the tripartite W state in a dissipatively coupled system, where one qubit and two resonators simultaneously interact …

[Phys. Rev. A 107, 012410] Published Fri Jan 06, 2023

Categories: Journals, Physics

Robust certification of unsharp instruments through sequential quantum advantages in a prepare-measure communication game

Fri, 2023-01-06 11:00

Author(s): Abhyoudai S. S., Sumit Mukherjee, and A. K. Pan

Communication games are one of the widely used tools that are designed to demonstrate quantum supremacy over classical resources in which two or more parties collaborate to perform an information processing task to achieve the highest success probability of winning the game. We propose a specific tw…

[Phys. Rev. A 107, 012411] Published Fri Jan 06, 2023

Categories: Journals, Physics

Incoherent Gaussian equivalence of $m$-mode Gaussian states

Thu, 2023-01-05 11:00

Author(s): Shuanping Du and Zhaofang Bai

Necessary and sufficient conditions for arbitrary multimode (pure or mixed) Gaussian states to be equivalent under incoherent Gaussian operations are derived. We show that two Gaussian states are incoherent equivalence if and only if they are related by incoherent unitaries. This builds the counterp…

[Phys. Rev. A 107, 012407] Published Thu Jan 05, 2023

Categories: Journals, Physics

Pure-state tomography with parallel unentangled measurements

Thu, 2023-01-05 11:00

Author(s): François Verdeil and Yannick Deville

Quantum state tomography (QST) aims at estimating a quantum state from averaged quantum measurements made on copies of that state. Most quantum algorithms rely on QST at some point and it is a well-explored topic in the literature, mostly for mixed states. In this paper we focus on the QST of a pure…

[Phys. Rev. A 107, 012408] Published Thu Jan 05, 2023

Categories: Journals, Physics

Optimal local work extraction from bipartite quantum systems in the presence of Hamiltonian couplings

Wed, 2023-01-04 11:00

Author(s): Raffaele Salvia, Giacomo De Palma, and Vittorio Giovannetti

We investigate the problem of finding the local analog of the ergotropy, which is the maximum work that can be extracted from a system if we can only apply local unitary transformation acting on a given subsystem. In particular, we provide a closed formula for the local ergotropy in the special case…

[Phys. Rev. A 107, 012405] Published Wed Jan 04, 2023

Categories: Journals, Physics