QUROPE Quantum Information Processing and Communication in Europe

Author(s): Xinan Chen, Yujie Zhang, Andreas Winter, Virginia O. Lorenz, and Eric Chitambar

Nonclassical features of quantum systems have the potential to strengthen the way we currently exchange information. In this paper, we explore this enhancement on the most basic level of single particles. To be more precise, we compare how well multiparty information can be transmitted to a single r…

[Phys. Rev. A 109, 062420] Published Thu Jun 13, 2024

Author(s): Natalie Klco and D. H. Beck

The electromagnetic trapping of ion chains can be regarded as a process of nontrivial entangled quantum state preparation within Hilbert spaces of the local axial motional modes. To begin uncovering properties of this entanglement resource produced as a by-product of conventional ion-trap quantum in…

[Phys. Rev. A 109, 062419] Published Thu Jun 13, 2024

Author(s): Jae-Gyun Baak and Uwe R. Fischer

We investigate the classical and quantum metrology of performing parameter estimation with interacting trapped bosons, which we theoretically treat by a self-consistent many-body approach of the multiconfigurational Hartree type. Focusing on a tilted double-well geometry, we compare a self-consisten…

[Phys. Rev. Lett. 132, 240803] Published Wed Jun 12, 2024

Author(s): Carlos de Gois and Matthias Kleinmann

Quantum state tomography is the standard technique for reconstructing a quantum state from experimental data. In the regime of finite statistics, experimental data cannot give perfect information about the quantum state. A common way to express this limited knowledge is by providing confidence regio…

[Phys. Rev. A 109, 062417] Published Wed Jun 12, 2024

Author(s): Ian George and Eric Chitambar

It is known that general convertibility of bipartite entangled states is not possible to arbitrary error without some classical communication. While some tradeoffs between communication cost and conversion error have been proven, these bounds can be very loose. In particular, there are many cases in…

[Phys. Rev. A 109, 062418] Published Wed Jun 12, 2024

Author(s): Boyu Gao and Natalie Klco

The reduction and distortion of quantum correlations in the presence of classical noise leads to varied levels of inefficiency in the availability of entanglement as a resource for quantum information processing protocols. While generically minimizing required entanglement for mixed quantum states r…

[Phys. Rev. A 109, 062413] Published Tue Jun 11, 2024

Author(s): Haorui Chen and Shengshi Pang

The quantum Zeno effect is a distinctive phenomenon in quantum mechanics, describing the nontrivial effect of frequent projective measurements on hindering the evolution of a quantum system. However, when subjected to environmental noise, the quantum system may dissipate, and the quantum Zeno effect…

[Phys. Rev. A 109, 062414] Published Tue Jun 11, 2024

Author(s): Laurin E. Fischer, Timothée Dao, Ivano Tavernelli, and Francesco Tacchino

Randomized measurement protocols such as classical shadows represent powerful resources for quantum technologies, with applications ranging from quantum state characterization and process tomography to machine learning and error mitigation. Recently, the notion of measurement dual frames, in which c…

[Phys. Rev. A 109, 062415] Published Tue Jun 11, 2024

Author(s): Shintaro Minagawa and Hayato Arai

With the recent development of quantum information theory, some attempts have been made to construct information theory beyond quantum theory. Here, we consider hypothesis-testing relative entropy and one-shot classical capacity, that is, the optimal rate of classical information transmitted by usin…

[Phys. Rev. A 109, 062416] Published Tue Jun 11, 2024

Author(s): Albie Chan, Zheng Shi, Luca Dellantonio, Wolfgang Dür, and Christine A. Muschik

Variational quantum eigensolvers (VQEs) are successful algorithms for studying physical systems on quantum computers. Recently, they were extended to the measurement-based model of quantum computing, bringing resource graph states and their advantages into the realm of quantum simulation. In this Le…

[Phys. Rev. Lett. 132, 240601] Published Tue Jun 11, 2024

Author(s): Ya-Li Mao, Hu Chen, Bixiang Guo, Shiting Liu, Zheng-Da Li, Ming-Xing Luo, and Jingyun Fan

Quantum networks promise unprecedented advantages in information processing and open up intriguing new opportunities in fundamental research, where network topology and network nonlocality fundamentally underlie these applications. Hence, the detections of network topology and nonlocality are crucia…

[Phys. Rev. Lett. 132, 240801] Published Tue Jun 11, 2024

Author(s): Lisa T. Weinbrenner, Nidhin Prasannan, Kiara Hansenne, Sophia Denker, Jan Sperling, Benjamin Brecht, Christine Silberhorn, and Otfried Gühne

Distributed quantum information in networks is paramount for global secure quantum communication. Moreover, it finds applications as a resource for relevant tasks, such as clock synchronization, magnetic field sensing, and blind quantum computation. For quantum network analysis and benchmarking of i…

[Phys. Rev. Lett. 132, 240802] Published Tue Jun 11, 2024

Author(s): Dan Lei, Disheng Guo, Jun Xin, and Xiao-Ming Lu

Attenuation and amplification are the most common processes for optical communications. Amplification can be used to compensate the attenuation of the complex amplitude of an optical field, but is unable to recover the coherence lost, provided that the attenuation channel and the amplification chann…

[Phys. Rev. A 109, 062410] Published Mon Jun 10, 2024

Author(s): Nihar Ranjan Dash, Sanjoy Dutta, R. Srikanth, and Subhashish Banerjee

Quantum error-correcting codes (QECCs) and decoherence-free subspace (DFS) codes provide active and passive means, respectively, to address certain types of errors that arise during quantum computation. The latter technique is suitable to correct correlated errors with certain symmetries and the for…

[Phys. Rev. A 109, 062411] Published Mon Jun 10, 2024

Author(s): Joonas Malmi, Keijo Korhonen, Daniel Cavalcanti, and Guillermo García-Pérez

In recent years, informationally complete measurements have attracted considerable attention, especially in the context of classical shadows. In the particular case of informationally overcomplete measurements, for which the number of possible outcomes exceeds the dimension of the space of linear op…

[Phys. Rev. A 109, 062412] Published Mon Jun 10, 2024

Author(s): Haiyan He, Kai Zhang, and Jietai Jing

Quantum coherent feedback control (CFC) has been widely applied to prepare and manipulate nonclassical beams. In this paper, we utilize an optical beam splitter with tunable reflectivity k as a feedback controller and theoretically construct a CFC system based on four-wave mixing (FWM) processes wit…

[Phys. Rev. A 109, 062409] Published Fri Jun 07, 2024

Author(s): Zi-Yong Ge, Yu-Ran Zhang, and Franco Nori

We investigate the meson excitations (particle-antiparticle bound states) in quantum many-body scars of a 1D Z2 lattice gauge theory coupled to a dynamical spin-12 chain as a matter field. By introducing a string representation of the physical Hilbert space, we express a scar state |Ψn,l⟩ as a super…

[Phys. Rev. Lett. 132, 230403] Published Fri Jun 07, 2024

Author(s): Benjamin Yadin, Satoya Imai, and Otfried Gühne

Quantum speed limits provide upper bounds on the rate with which a quantum system can move away from its initial state. Here, we provide a different kind of speed limit, describing the divergence of a perturbed open system from its unperturbed trajectory. In the case of weak coupling, we show that t…

[Phys. Rev. Lett. 132, 230404] Published Fri Jun 07, 2024

Author(s): Matthew S. Winnel, Joshua J. Guanzon, Deepesh Singh, and Timothy C. Ralph

Large-amplitude squeezed cat states and high-quality Gottesman-Kitaev-Preskill (GKP) states are essential for effective quantum error correction, yet their optical preparation has been hindered by challenges such as low success probabilities, small amplitudes, and insufficient squeezing. Addressing …

[Phys. Rev. Lett. 132, 230602] Published Fri Jun 07, 2024

Author(s): Xiao-Dong Zhang, Bin-Bin Cai, and Song Lin

In this paper we propose two classes of multiparticle entangled states: multigraph and multihypergraph states. Two types of operations are designed to correspond to the edges and hyperedges to prepare the states. Furthermore, multigraph and multihypergraph states contain qudit graph and hypergraph s…

[Phys. Rev. A 109, 062407] Published Thu Jun 06, 2024