QUROPE Quantum Information Processing and Communication in Europe

Author(s): Xinyu Qiu, Lin Chen, and Li-Jun Zhao

Quantifying the effect of noise on unitary operations is an essential task in quantum information processing. We propose the quantum Wasserstein distance between unitary operations, which shows an explanation for quantum circuit complexity and characterizes the local distinguishability of multiqudit…

[Phys. Rev. A 110, 012412] Published Mon Jul 01, 2024

Author(s): Hao Sun, Fenzhuo Guo, Haifeng Dong, and Fei Gao

Quantum network nonlocality sharing provides a unique perspective for constructing large-scale quantum networks and holds promise for numerous potential applications. In this paper we demonstrate the network nonlocality sharing via unsharp measurements in a two-forked n-layer tree-shaped network, wh…

[Phys. Rev. A 110, 012401] Published Mon Jul 01, 2024

Author(s): Ran Liu, Xiaodong Yang, and Jun Li

Resisting diverse noise effects is crucial for the accurate manipulation of quantum systems. For static or slowly varying noises, many efficient noise mitigation strategies have been developed, such as composite pulses and dynamical decoupling. However, for fast fluctuating noise in the Markovian li…

[Phys. Rev. A 110, 012402] Published Mon Jul 01, 2024

Author(s): Maciej Demianowicz, Kajetan Vogtt, and Remigiusz Augusiak

We introduce a class of entangled subspaces: completely entangled subspaces of entanglement depth k (k−CESs). These are subspaces of multipartite Hilbert spaces containing only pure states with an entanglement depth of at least k. We present an efficient construction of k−CESs of any achievable dime…

[Phys. Rev. A 110, 012403] Published Mon Jul 01, 2024

Author(s): Alexey Uvarov, Daniil Rabinovich, Olga Lakhmanskaya, Kirill Lakhmanskiy, Jacob Biamonte, and Soumik Adhikary

Variational quantum algorithms have emerged as a cornerstone of contemporary quantum algorithms research. Practical implementations of these algorithms, despite offering certain levels of robustness against systematic errors, show a decline in performance due to the presence of stochastic errors and…

[Phys. Rev. A 110, 012404] Published Mon Jul 01, 2024

Author(s): Yu Guo

Multipartite entanglement includes not only the genuine entanglement but also the k-entanglement (k⩾2). It is known that the most bipartite entanglement measures have been shown to be monogamous, but the monogamy relation is involved in the bipartite entanglement measures rather than the multipartit…

[Phys. Rev. A 110, 012405] Published Mon Jul 01, 2024

Author(s): Si-Yuan Qi, Geni Gupur, Yu-Chun Wu, and Guo-Ping Guo

Equivalence between positive partial transpose (PPT) entanglement and bound entanglement is a long-standing open problem in quantum information theory. Limited progress has been made so far, even on the seemingly simple case of the bound entanglement of Werner states. The primary challenge is to giv…

[Phys. Rev. A 110, 012406] Published Mon Jul 01, 2024

Author(s): Paweł Cieśliński, Paweł Kurzyński, Tomasz Sowiński, Waldemar Kłobus, and Wiesław Laskowski

The investigation of many-body interactions holds significant importance for both quantum foundations and information. Hamiltonians coupling multiple particles at once, beyond other applications, can lead to faster entanglement generation, multiqubit gate implementation, and improved error correctio…

[Phys. Rev. A 110, 012407] Published Mon Jul 01, 2024

Author(s): Anaelle Hertz, Aaron Z. Goldberg, and Khabat Heshami

The quadrature coherence scale (QCS) is a recently introduced measure that was shown to be an efficient witness of nonclassicality. It takes a simple form for pure and Gaussian states, but a general expression for mixed states tends to be prohibitively unwieldy. In this paper we introduce a method f…

[Phys. Rev. A 110, 012408] Published Mon Jul 01, 2024

Author(s): Yudai Suzuki and Muyuan Li

Quantum kernel methods have been actively examined from both theoretical and practical perspectives due to the potential of quantum advantage in machine learning tasks. Despite a provable advantage of fine-tuned quantum kernels for specific problems, widespread practical usage of quantum kernel meth…

[Phys. Rev. A 110, 012409] Published Mon Jul 01, 2024

Author(s): Sudipta Das, Rivu Gupta, Himadri Shekhar Dhar, and Aditi Sen(De)

The telecloning protocol distributes quantum states from a single sender to multiple receivers via a shared entangled state by exploiting the notions of teleportation and approximate cloning. We investigate the optimal telecloning fidelities obtained using both Gaussian and non-Gaussian shared resou…

[Phys. Rev. A 110, 012410] Published Mon Jul 01, 2024

Author(s): Paulo J. Paulino, Igor Lesanovsky, and Federico Carollo

The state of an open quantum system undergoing an adiabatic process evolves by following the instantaneous stationary state of its time-dependent generator. This observation allows one to characterize, for a generic adiabatic evolution, the average dynamics of the open system. However, information a…

[Phys. Rev. Lett. 132, 260402] Published Fri Jun 28, 2024

Author(s): Marcin Łobejko, Tanmoy Biswas, Paweł Mazurek, and Michał Horodecki

We demonstrate how to incorporate a catalyst to enhance the performance of a heat engine. Specifically, we analyze efficiency in one of the simplest engine models, which operates in only two strokes and comprises of a pair of two-level systems, potentially assisted by a d-dimensional catalyst. When …

[Phys. Rev. Lett. 132, 260403] Published Fri Jun 28, 2024

Author(s): Jiu-Peng Chen, Fei Zhou, Chi Zhang, Cong Jiang, Fa-Xi Chen, Jia Huang, Hao Li, Li-Xing You, Xiang-Bin Wang, Yang Liu, Qiang Zhang, and Jian-Wei Pan

Twin-field quantum key distribution (TFQKD) overcomes the linear rate-loss limit, which promises a boost of secure key rate over long distance. However, the complexity of eliminating the frequency differences between the independent laser sources hinders its practical application. We analyzed and de…

[Phys. Rev. Lett. 132, 260802] Published Fri Jun 28, 2024

Author(s): Mark Buchanan

A theoretical model for the illumination of photosynthesizing algae in giant clams suggests principles for high efficiency collection of sunlight.

[Physics 17, 106] Published Fri Jun 28, 2024

Author(s): Huan Zhang, Ying Xia, Wei Ye, Shoukang Chang, and Zeyang Liao

Quantum illumination is a quantum sensing protocol primarily used for object detection, which aims to detect the presence of a target with low reflectivity in the free space using quantum light fields. Here we investigate a quantum illumination scheme using an entangled light source by performing no…

[Phys. Rev. A 109, 062440] Published Fri Jun 28, 2024

Author(s): Daniel Honciuc Menendez, Annie Ray, and Michael Vasmer

Quantum computers promise to solve problems that are intractable for classical computers, but qubits are vulnerable to many sources of error, limiting the depth of the circuits that can be reliably executed on today's quantum hardware. Quantum error correction has been proposed as a solution to this…

[Phys. Rev. A 109, 062438] Published Fri Jun 28, 2024

Author(s): B. Sharmila, F. M. Souza, H. M. Vasconcelos, and L. Sanz

We investigate the generation of an entangled electron pair emerging from a system composed of two quantum dots attached to a superconductor Cooper-pair beam splitter. We take into account three processes: crossed Andreev reflection, cotunneling, and Coulomb interaction. Together, these processes pl…

[Phys. Rev. A 109, 062439] Published Fri Jun 28, 2024

Author(s): Patryk Lipka-Bartosik, Henrik Wilming, and Nelly H. Y. Ng

A branch of quantum information is concerned with transformations that are possible given certain resources: for example, quantum teleportation moves a quantum state from one place to another, aided by entanglement and classical communication. Certain other tasks are provably impossible. But, as surveyed in this review, a surprising fact is that some tasks become possible if another quantum state is present, even if this state is returned untouched at the end of the task. This “quantum catalysis” enables a large variety of interesting tasks, with applications ranging from cryptography to thermodynamics.

[Rev. Mod. Phys. 96, 025005] Published Thu Jun 27, 2024

Author(s): Xingrui Song, Flavio Salvati, Chandrashekhar Gaikwad, Nicole Yunger Halpern, David R. M. Arvidsson-Shukur, and Kater Murch

Quantum sensing can benefit from entanglement protocols that can be interpreted as allowing qubits to go backward in time to choose an optimal initial state.

[Phys. Rev. Lett. 132, 260801] Published Thu Jun 27, 2024