QUROPE Quantum Information Processing and Communication in Europe

Author(s): Eyal Buks

Multistability is experimentally observed in a variety of quantum systems but cannot be derived from any theoretical model that is based on a monostable master equation. The author investigates the relation between disentanglement and multistability in the few-spin transverse Ising model and finds that multistability can be obtained in the presence of spontaneous disentanglement.

[Phys. Rev. A 110, 012439] Published Mon Jul 15, 2024

Author(s): Katarzyna Siudzińska

We use symmetric measurement operators to construct quantum channels that provide a further generalization of generalized Pauli channels. The resulting maps are bistochastic but, in general, no longer mixed unitary. We analyze their important properties, such as complete positivity and the ability t…

[Phys. Rev. A 110, 012440] Published Mon Jul 15, 2024

Author(s): Ming Yang, Dongkai Zhang, and Lixiang Chen

Recent advancements have expanded Hardy's nonlocality arguments into multisetting and multidimensional systems to enhance quantum correlations. In comparison with Hardy's nonlocality argument, Cabello's nonlocality argument (CNA) emerges as a superior choice for illustrating nonlocal features. An op…

[Phys. Rev. A 110, 012441] Published Mon Jul 15, 2024

Author(s): Zi-Jian Xu and Jun-Hong An

Permitting the transmission of unknown quantum states over long distances by using entanglement, quantum teleportation serves as an important building block for many quantum technologies. However, in the noisy intermediate-scale quantum era, the practical realization of quantum teleportation is inev…

[Phys. Rev. A 110, 012442] Published Mon Jul 15, 2024

Author(s): M. Yassine Naghmouchi and Wesley da Silva Coelho

This paper presents a hybrid classical-quantum approach to solve mixed-integer linear programming (MILP) using neutral-atom quantum computations. We apply Benders decomposition (BD) to segment MILPs into a master problem (MP) and a subproblem, where the MP is addressed using a neutral-atom device, a…

[Phys. Rev. A 110, 012434] Published Fri Jul 12, 2024

Author(s): Ashutosh Goswami, Mehdi Mhalla, and Valentin Savin

A fault-tolerant way to prepare logical code states of Q1 codes, i.e., quantum polar codes encoding one qubit, was recently proposed. The fault tolerance therein is guaranteed by an error detection gadget, where, if an error is detected during the preparation, one entirely discards the preparation. …

[Phys. Rev. A 110, 012438] Published Fri Jul 12, 2024

Author(s): Steven Herbert, Julien Sorci, and Yao Tang

We give an explicit construction to perform any n-qubit computational-basis-state transposition using Θ(n) gates. This nearly coincides with the lower bound Ω[n/log(nd)] on worst-case and average-case gate complexities to perform transpositions using a d-element gate set, which we also prove.

[Phys. Rev. A 110, 012437] Published Fri Jul 12, 2024

Author(s): Ming-Ming Wang and Xiao-Ying Zhang

Bayesian networks are powerful tools for probabilistic analysis and have been widely used in machine learning and data science. Unlike the time-consuming parameter training process of neural networks, Bayes classifiers constructed on Bayesian networks can make decisions based solely on statistical d…

[Phys. Rev. A 110, 012433] Published Fri Jul 12, 2024

Author(s): Jack Ceroni, Ian MacCormack, and Guillaume Verdon

We provide a rigorous proof of the approximate convergence of sliding-window quantum belief-propagation as outlined heuristically in the work of Bilgin and Poulin [Phys. Rev. B 81, 054106 (2010)], in the absence of the quantum Markov property. In particular, we confirm the hypothesis outlined in thi…

[Phys. Rev. A 110, 012435] Published Fri Jul 12, 2024

Author(s): Kan Takase, Fumiya Hanamura, Hironari Nagayoshi, J. Eli Bourassa, Rafael N. Alexander, Akito Kawasaki, Warit Asavanant, Mamoru Endo, and Akira Furusawa

The generation of a logical qubit called the Gottesman-Kitaev-Preskill (GKP) qubit in an optical traveling wave is a major challenge for realizing large-scale universal fault-tolerant optical quantum computers. Recently, probabilistic generation of elementary GKP qubits has been demonstrated using p…

[Phys. Rev. A 110, 012436] Published Fri Jul 12, 2024

Author(s): Akshay Seshadri, Martin Ringbauer, Jacob Spainhour, Thomas Monz, and Stephen Becker

Estimating the fidelity with a target state is important in quantum information tasks. Many fidelity-estimation techniques present a suitable measurement scheme to perform the estimation. In contrast, we present techniques that allow the experimentalist to choose a convenient measurement setting. Ou…

[Phys. Rev. A 110, 012431] Published Wed Jul 10, 2024

Author(s): Shuyue Wang, Wuji Zhang, Chunfang Sun, Chunfeng Wu, and Gangcheng Wang

In this study we engineer the z component of the Dzyaloshinskii-Moriya interaction mediated by photons to emulate ground-state chiral excitation based on three-level atoms driven by quantum and classical fields. We employ adiabatic elimination techniques to derive an effective Dzyaloshinskii-Moriya …

[Phys. Rev. A 110, 012432] Published Wed Jul 10, 2024

Author(s): Abdul Basit, Hamad Ali, Gao Xianlong, Peng-Bo Li, Gehad Sadiek, and Hichem Eleuch

The entropic uncertainty relation imposes a limit on the accuracy of measurement outcomes of two conjugate observables, which can be reduced in the presence of quantum memory. We theoretically study the dynamical behaviors of the quantum-memory-assisted entropic uncertainty relation for a bipartite …

[Phys. Rev. A 110, 012429] Published Tue Jul 09, 2024

Author(s): Peter Brearley and Sylvain Laizet

A quantum algorithm for solving the advection equation by embedding the discrete time-marching operator into Hamiltonian simulations is presented. One-dimensional advection can be simulated directly since the central finite-difference operator for first-order derivatives is anti-Hermitian. Here this…

[Phys. Rev. A 110, 012430] Published Tue Jul 09, 2024

Author(s): Mingjian He and Shouyin Liu

Continuous variable quantum teleportation provides a path to the long-distance transmission of quantum states. Photon-varying non-Gaussian operations have been shown to improve the fidelity of quantum teleportation when integrated into the protocol. However, for a given type of non-Gaussian operatio…

[Phys. Rev. A 110, 012425] Published Tue Jul 09, 2024

Author(s): P. Z. Zhao and Jiangbin Gong

Nonadiabatic holonomic operations are based on nonadiabatic non-Abelian geometric phases, hence possessing the inherent geometric features for robustness against control errors. However, nonadiabatic holonomic operations are still sensitive to the systematic amplitude error induced by imperfect cont…

[Phys. Rev. A 110, 012426] Published Tue Jul 09, 2024

Author(s): Mingzhao Liu (刘铭钊) and Charles T. Black

This paper presents a computational analysis of a superconducting transmon qubit design, in which the superconductor-insulator-superconductor (SIS) Josephson junction is replaced by a coplanar, superconductor-constriction-superconductor (ScS) nanobridge junction. Within the scope of Ginzburg-Landau …

[Phys. Rev. A 110, 012427] Published Tue Jul 09, 2024

Author(s): Ernesto Campos, Daniil Rabinovich, and Alexey Uvarov

Variational quantum algorithms have become the de facto model for current quantum computations. A prominent example of such algorithms—the quantum approximate optimization algorithm (QAOA)—was originally designed for combinatorial optimization tasks, but has been shown to be successful for a variety…

[Phys. Rev. A 110, 012428] Published Tue Jul 09, 2024

Author(s): Shuyang Meng, Fionnuala Curran, Gabriel Senno, Victoria J. Wright, Máté Farkas, Valerio Scarani, and Antonio Acín

Quantum states possess an intrinsic form of randomness, inaccessible even to an all-powerful eavesdropper. The authors find concise mathematical expressions for the maximal intrinsic randomness that can be extracted from any quantum state, as quantified by the conditional min-, von Neumann and max-entropies. They also characterize the optimal (and inequivalent) measurements in each case.

[Phys. Rev. A 110, L010403] Published Mon Jul 08, 2024

Author(s): Dávid Pataki, Áron Márton, János K. Asbóth, and András Pályi

Quantum error correction is a key challenge for the development of practical quantum computers, a direction in which significant experimental progress has been made in recent years. In solid-state qubits, one of the leading information loss mechanisms is dephasing, usually modeled by phase-flip erro…

[Phys. Rev. A 110, 012417] Published Mon Jul 08, 2024