QUROPE Quantum Information Processing and Communication in Europe

Author(s): Giulio Chiribella, Lorenzo Giannelli, and Carlo Maria Scandolo

If classical systems were to coexist with “anticlassical” systems (coined here) then an observer with access to both systems could measure Bell nonlocality and other nonclassical features.

[Phys. Rev. Lett. 132, 190201] Published Tue May 07, 2024

Author(s): Owen Diba, Harry J. D. Miller, Jake Iles-Smith, and Ahsan Nazir

Determining the statistics of work done on a quantum system while strongly coupled to a reservoir is a formidable task, requiring the calculation of the full eigenspectrum of the combined system and reservoir. Here, we show that this issue can be circumvented by using a polaron transformation that m…

[Phys. Rev. Lett. 132, 190401] Published Tue May 07, 2024

Author(s): Temple He, Veronika E. Hubeny, and Massimiliano Rota

We show via explicit construction that all the extreme rays of both the three-party quantum entropy cone and the four-party stabilizer entropy cone can be obtained from subsystem coarse grainings of specific higher-party quantum states, namely, extreme states characterized by saturating a (nontrivia…

[Phys. Rev. A 109, 052407] Published Mon May 06, 2024

Author(s): Julien Pinske and Jan Sperling

A protocol for regulating the distribution of quantum information between multiple parties is put forward. To prohibit the unrestricted distribution of quantum-resource states in a public quantum network, agents can apply a resource-destroying map to each sender's channel. Since resource-destroying …

[Phys. Rev. A 109, 052408] Published Mon May 06, 2024

Author(s): Ludovico Lami, Bartosz Regula, and Alexander Streltsov

Not all entanglement is distillable, i.e., extractable in pure form. In this work, the authors show that being assisted by catalysts, which generally can help transform quantum states, is not enough to change this; certain entangled states will stay “bound entangled” even when catalysts are allowed.

[Phys. Rev. A 109, L050401] Published Fri May 03, 2024

Author(s): Xinwei Lee, Xinjian Yan, Ningyi Xie, Dongsheng Cai, Yoshiyuki Saito, and Nobuyoshi Asai

The capability of the quantum approximate optimization algorithm (QAOA) in solving combinatorial optimization problems has been intensively studied in recent years due to its application in the quantum-classical hybrid regime. Despite having difficulties that are innate in the variational quantum al…

[Phys. Rev. A 109, 052406] Published Thu May 02, 2024

Author(s): Ting Zhang, Yukun Zhang, Lu Liu, Xiao-Xu Fang, Qian-Xi Zhang, Xiao Yuan, and He Lu

Noise is, in general, inevitable and detrimental to practical and useful quantum communication and computation. Under the resource theory framework, resource distillation serves as a generic tool to overcome the effect of noise. Yet, conventional resource distillation protocols generally require ope…

[Phys. Rev. Lett. 132, 180201] Published Thu May 02, 2024

Author(s): Naoto Shiraishi and Ryuji Takagi

Quantum coherence is one of the fundamental aspects distinguishing classical and quantum theories. Coherence between different energy eigenstates is particularly important, as it serves as a valuable resource under the law of energy conservation. A fundamental question in this setting is how well on…

[Phys. Rev. Lett. 132, 180202] Published Thu May 02, 2024

Author(s): Akshay Koottandavida, Ioannis Tsioutsios, Aikaterini Kargioti, Cassady R. Smith, Vidul R. Joshi, Wei Dai, James D. Teoh, Jacob C. Curtis, Luigi Frunzio, Robert J. Schoelkopf, and Michel H. Devoret

Dual-rail erasure qubits are characterized in a superconducting cavity architecture that allows for an improved error correction.

[Phys. Rev. Lett. 132, 180601] Published Thu May 02, 2024

Author(s): Xiao-Yi Lai, Ren-Zhou Fang, Tao Li, Ren-Zhu Su, Jia Huang, Hao Li, Li-Xing You, Xiao-Hui Bao, and Jian-Wei Pan

Solid-state qubits with a photonic interface is very promising for quantum networks. Color centers in silicon carbide have shown excellent optical and spin coherence, even when integrated with membranes and nanostructures. Additionally, nuclear spins coupled with electron spins can serve as long-liv…

[Phys. Rev. Lett. 132, 180803] Published Thu May 02, 2024

Author(s): Erik Hesselmeier, Pierre Kuna, Wolfgang Knolle, Florian Kaiser, Nguyen Tien Son, Misagh Ghezellou, Jawad Ul-Hassan, Vadim Vorobyov, and Jörg Wrachtrup

Quantum state readout is a key requirement for a successful qubit platform. In this work, we demonstrate a high-fidelity quantum state readout of a V2 center nuclear spin based on a repetitive readout technique. We demonstrate up to 99.5% readout fidelity and 99% for state preparation. Using this ef…

[Phys. Rev. Lett. 132, 180804] Published Thu May 02, 2024

Author(s): Yuanhao Li, Yangyang Fei, Weilong Wang, Xiangdong Meng, Hong Wang, Qianheng Duan, Yu Han, and Zhi Ma

Continuous-variable source-independent quantum random-number generators (CV-SI-QRNGs) generate high-speed secure random numbers without any assumptions about source. Recently, Smith et al. [Phys. Rev. A 99, 062326 (2019)] proposed a CV-SI-QRNG with phase-randomized local oscillator (LO) protocol, wh…

[Phys. Rev. A 109, 052401] Published Wed May 01, 2024

Author(s): Daer Feng and Shengshi Pang

The quantum walk is a quantum counterpart of the classical random walk that exhibits nonclassical behaviors and outperforms the classical random walk in various aspects. It has been known that a single particle can be propagated by a discrete-time quantum walk with a quadratic time scaling in the va…

[Phys. Rev. A 109, 052402] Published Wed May 01, 2024

Author(s): Woo-Ram Lee, Ryan Scott, and V. W. Scarola

Quantum simulation advantage over classical memory limitations would allow compact quantum circuits to yield insight into intractable quantum many-body problems, but the interrelated obstacles of large circuit depth in quantum time evolution and noise seem to rule out unbiased quantum simulation in …

[Phys. Rev. A 109, 052403] Published Wed May 01, 2024

Author(s): A. Barış Özgüler and Joshua A. Job

Qudit gates for high-dimensional quantum computing can be synthesized with high precision using numerical quantum optimal control techniques. Large circuits are broken down into modules and the tailored pulses for each module can be used as primitives for a qudit compiler. Application of the pulses …

[Phys. Rev. A 109, 052404] Published Wed May 01, 2024

Author(s): Priyabrata Char, Ajoy Sen, Amit Bhar, Indrani Chattopadhyay, and Debasis Sarkar

We explore the potential impact of the recently introduced correlated approximate catalytic procedure on quantum information processing tasks, particularly focusing on phase and subchannel discrimination protocols. Our findings reveal that the correlated catalyst substantially enhances the efficienc…

[Phys. Rev. A 109, 052405] Published Wed May 01, 2024

Author(s): Senrui Chen, Changhun Oh, Sisi Zhou, Hsin-Yuan Huang, and Liang Jiang

Quantum entanglement is a crucial resource for learning properties from nature, but a precise characterization of its advantage can be challenging. In this Letter, we consider learning algorithms without entanglement to be those that only utilize states, measurements, and operations that are separab…

[Phys. Rev. Lett. 132, 180805] Published Wed May 01, 2024

Author(s): Su-Yong Lee, Jihwan Kim, Zaeill Kim, and Duk Y. Kim

Entanglement is beneficial to enhancing a phase sensitivity beyond the classical limit that is given by a coherent state. The best performance is achieved with symmetric entangled states, which is enhanced further by sending more photons to the signal mode. We delve into which entanglement structure…

[Phys. Rev. A 109, 042429] Published Tue Apr 30, 2024

Author(s): Yue-Hao Yin, Jin-Xin Yang, and Li-Xiang Cen

We propose a chirped-pulse driving protocol and reveal its exceptional property for quantum coherent control. The nonadiabatic passage generated by the driving protocol, which includes the population inversion and the nonadiabaticity-induced transition as its ingredients, is shown to be robust again…

[Phys. Rev. A 109, 042430] Published Tue Apr 30, 2024

Author(s): J.-W. Zhang, B. Wang, W.-F. Yuan, J.-C. Li, J.-T. Bu, G.-Y. Ding, W.-Q. Ding, L. Chen, F. Zhou, and M. Feng

Although entanglement is considered as an essential resource for quantum information processing, whether entanglement helps for energy conversion or output in the quantum regime is still lack of experimental witness. Here, we report on an energy-conversion device operating as a quantum engine with t…

[Phys. Rev. Lett. 132, 180401] Published Tue Apr 30, 2024