QUROPE Quantum Information Processing and Communication in Europe

Author(s): Hai-Jun Xing

The efficiency of quantum measurements in distinguishing neighboring quantum states is a central topic in quantum information sciences. We study the efficiency of vertex measurement in two-parameter estimation from the information geometry perspective, where the vertex measurement is a rare typical …

[Phys. Rev. A 110, 012449] Published Mon Jul 22, 2024

Author(s): Yang-Guang Shan, Yao Zhou, Zhen-Qiang Yin, Shuang Wang, Wei Chen, De-Yong He, Guang-Can Guo, and Zheng-Fu Han

Twin-field (TF) quantum key distribution (QKD) has been extensively researched because of its long transmission distance. The phase-encoding TF-QKD can realize both a high key rate and a long transmission distance, so it has attracted a lot of attention. In this article, we are inspired by the sendi…

[Phys. Rev. A 110, 012450] Published Mon Jul 22, 2024

Author(s): Ahana Ghoshal and Ujjwal Sen

We obtain a Gorini-Kossakowski-Sudarshan-Lindblad-like master equation for two or more quantum systems connected locally to a combination of Markovian and non-Markovian heat baths. The master equation was originally formulated for multiparty systems with either exclusively Markovian or non-Markovian…

[Phys. Rev. A 110, 012451] Published Mon Jul 22, 2024

Author(s): Xuanran Zhu, Chao Zhang, and Bei Zeng

Determining whether a subspace spanned by certain quantum states is entangled and its entanglement dimensionality remains a fundamental challenge in quantum information science. This paper introduces a geometric measure of r-bounded rank, Er(S), for a given subspace S. Derived from the established g…

[Phys. Rev. A 110, 012452] Published Mon Jul 22, 2024

Author(s): Shilin Huang and Shruti Puri

Quantum error correction (QEC) with single-shot decoding enables the reduction of errors after every single round of noisy stabilizer measurement, easing the time-overhead requirements for fault tolerance. Notably, several classes of quantum low-density parity check (qLDPC) codes are known which fac…

[Phys. Rev. A 110, 012453] Published Mon Jul 22, 2024

Author(s): Chengkai Zhu, Yin Mo, Yu-Ao Chen, and Xin Wang

The inherent irreversibility of quantum dynamics for open systems poses a significant barrier to the inversion of unknown quantum processes. To tackle this challenge, we propose the framework of virtual combs that exploits the unknown process iteratively with additional classical postprocessing to s…

[Phys. Rev. Lett. 133, 030801] Published Fri Jul 19, 2024

Author(s): Rachel Berkowitz

A new technique reveals high-speed trajectories of oscillating vortices and shows that they are 10,000 times lighter than expected.

[Physics 17, 117] Published Fri Jul 19, 2024

Author(s): Martin Rodriguez-Vega

Researchers predict that a twisted graphene bilayer excited with light could host a slow-moving acoustic plasmon.

[Physics 17, s91] Published Fri Jul 19, 2024

Author(s): Rui Li, Junling Du, Zheng Qin, Shikun Zhang, Chunxiao Du, Yang Zhou, and Zhisong Xiao

Quantum entanglement plays a pivotal role in various quantum information processing tasks. However, a universal and effective way to detect entanglement structures is still lacking, especially for high-dimensional and multipartite quantum systems. Noticing the mathematical similarities between the c…

[Phys. Rev. A 110, 012448] Published Fri Jul 19, 2024

Author(s): Gekko Budiutama, Shunsuke Daimon, Hirofumi Nishi, Ryui Kaneko, Tomi Ohtsuki, and Yu-ichiro Matsushita

Quantum convolutional neural networks (QCNNs) have gathered attention as one of the most promising algorithms for quantum machine learning. Reduction in the cost of training as well as improvement in performance are required for practical implementation of these models. In this study, we propose a c…

[Phys. Rev. A 110, 012447] Published Fri Jul 19, 2024

Author(s): Katherine Wright

Researchers have developed a cancer-detection method that uses painless sound waves, rather than a torturing needle, to obtain genetic information about a patient’s cancer.

[Physics 17, 116] Published Thu Jul 18, 2024

Author(s): Ryan Wilkinson

A new theory that accounts for disorder in a protein’s structure sheds light on the development inside a cell of tiny droplets that are vital to a cell’s function.

[Physics 17, s82] Published Thu Jul 18, 2024

Author(s): Mirko Consiglio, Jacopo Settino, Andrea Giordano, Carlo Mastroianni, Francesco Plastina, Salvatore Lorenzo, Sabrina Maniscalco, John Goold, and Tony J. G. Apollaro

The preparation of an equilibrium thermal state of a quantum many-body system on noisy intermediate-scale quantum (NISQ) devices is an important task in order to extend the range of applications of quantum computation. Faithful Gibbs state preparation would pave the way to investigate protocols such…

[Phys. Rev. A 110, 012445] Published Thu Jul 18, 2024

Author(s): Göktuğ Karpat and Barış Çakmak

We examine the emergence of dynamical memory effects in quantum processes having indefinite time direction and causal order. In particular, we focus on the class of phase-covariant qubit channels, which encompasses some of the most significant paradigmatic open quantum system models. In order to ass…

[Phys. Rev. A 110, 012446] Published Thu Jul 18, 2024

Author(s): Tatsuhiko N. Ikeda, Sho Sugiura, and Anatoli Polkovnikov

An external periodic (Floquet) drive is believed to bring any initial state to the featureless infinite temperature state in generic nonintegrable isolated quantum many-body systems in the thermodynamic limit, irrespective of the driving frequency Ω. However, numerical or analytical evidence either …

[Phys. Rev. Lett. 133, 030401] Published Wed Jul 17, 2024

Author(s): Eric Kubischta and Ian Teixeira

We introduce twisted unitary t-groups, a generalization of unitary t-groups under a twisting by an irreducible representation. We then apply representation theoretic methods to the Knill-Laflamme error correction conditions to show that twisted unitary t-groups automatically correspond to quantum co…

[Phys. Rev. Lett. 133, 030602] Published Wed Jul 17, 2024

Author(s): Charles Day

The pressures at which some elements start superconducting are so high that making detailed measurements of the transition has been impossible—until now.

[Physics 17, s84] Published Wed Jul 17, 2024

Author(s): Rajdeep Paul, Souradeep Sasmal, and A. K. Pan

Self-testing protocols refer to novel device-independent certification schemes wherein the devices are uncharacterized and the dimension of the system remains unspecified. The optimal quantum violation of Bell's inequality facilitates such self-testing. In this work we put forth a protocol for self-…

[Phys. Rev. A 110, 012444] Published Wed Jul 17, 2024

Author(s): Ivan Medina, Alexandre Drinko, Guilherme I. Correr, Pedro C. Azado, and Diogo O. Soares-Pinto

The energy extraction from quantum sources is a key task to develop new quantum devices such as quantum batteries (QB). In this context, one of the main figures of merit is the ergotropy, which measures the maximal amount of energy (as work) that can be extracted from the quantum source by means of …

[Phys. Rev. A 110, 012443] Published Wed Jul 17, 2024

Author(s): Simon Lieu, Yu-Jie Liu, and Alexey V. Gorshkov

An interesting problem in the field of quantum error correction involves finding a physical system that hosts a “passively protected quantum memory,” defined as an encoded qubit coupled to an environment that naturally wants to correct errors. To date, a quantum memory stable against finite-temperat…

[Phys. Rev. Lett. 133, 030601] Published Tue Jul 16, 2024