QUROPE Quantum Information Processing and Communication in Europe

Author(s): Chandrima B. Pushpan, Harikrishnan K J, Prithvi Narayan, and Amit Kumar Pal

We consider the isotropic Heisenberg model in a magnetic field in the strong-rung-coupling limit on a two-dimensional (2D) rectangular zig-zag lattice of arbitrary size, and determine the one-dimensional (1D) effective model representing the low-energy manifold of the 2D model up to second order in …

[Phys. Rev. A 110, 032408] Published Mon Sep 09, 2024

Author(s): Louis Schatzki, Linjian Ma, Edgar Solomonik, and Eric Chitambar

Graph states play an important role in quantum information theory through their connection to measurement-based computing and error correction. Prior work revealed elegant connections between the graph structure of these states and their multipartite entanglement. We continue this line of investigat…

[Phys. Rev. A 110, 032409] Published Mon Sep 09, 2024

Author(s): Guo Yao Tham, Ranjith Nair, and Mile Gu

In covert target detection, Alice attempts to send optical or microwave probes to determine the presence or absence of a weakly reflecting target embedded in thermal background radiation within a target region, while striving to remain undetected by an adversary, Willie, who is co-located with the t…

[Phys. Rev. Lett. 133, 110801] Published Mon Sep 09, 2024

Author(s): Julien Roche

A new technique allows researchers to study how a bacterium’s entire set of proteins changes its shape under high pressures—shedding light on adaptation mechanisms of deep-sea organisms.

[Physics 17, 132] Published Mon Sep 09, 2024

Author(s): Ming-jie Liao, Mei-Song Wei, Yi-Qing Wang, Jingping Xu, and Yaping Yang

We demonstrate a controllable and tunable topological beam splitter with a multiport based on the one-dimensional extended Su-Schrieffer-Heeger model, which supports the topological interface by introducing the nearest-neighbor (NN) coupling defect at the central site. The quantum state initially pr…

[Phys. Rev. A 110, 032406] Published Fri Sep 06, 2024

Author(s): Mark Buchanan

Researchers use ultrashort laser pulses to trigger a spin-aligned electron flow on the few-femtosecond timescale—opening up a possible path toward faster spintronic devices.

[Physics 17, 131] Published Fri Sep 06, 2024

Author(s): Xi Lu, Wojciech Górecki, Chiara Macchiavello, and Lorenzo Maccone

We give two upper bounds to the mutual information in arbitrary quantum estimation strategies. The first is based on some simple Fourier properties of the estimation apparatus. The second is derived using the first, but, interestingly, depends only on the Fisher information of the parameter, so it i…

[Phys. Rev. A 110, 032405] Published Thu Sep 05, 2024

Author(s): Marric Stephens

Researchers have isolated a high-order term in the behavior of a Josephson junction, which could lead to longer-lived superconducting qubits.

[Physics 17, s107] Published Thu Sep 05, 2024

Author(s): Ben-yuan Zhou, Ni Pan, Li Yu, and Gao-xiang Li

We propose a scheme to manipulate entanglement and the direction of asymmetric Einstein-Podolsky-Rosen (EPR) steering between two interacting bosonic modes in a nonlinear optical apparatus, in which a pumped Fabry-Pérot cavity system containing two nonlinear waveguides is coupled to two feedback loo…

[Phys. Rev. A 110, 032401] Published Wed Sep 04, 2024

Author(s): Brendan Pankovich, Alex Neville, Angus Kan, Srikrishna Omkar, Kwok Ho Wan, and Kamil Brádler

Entangled dual-rail photonic qubit states are important resource states for measurement-based and fusion-based quantum computing. However, their generation is highly challenging due to the probabilistic nature of entangling operations. Here, the authors introduce a formalism using ZX diagrams to design linear optical systems that can generate entangled multiqubit states of dual-rail photonic qubits. This formalism makes it easier to compare methods for creating a desired photonic state and to find the most optimal one.

[Phys. Rev. A 110, 032402] Published Wed Sep 04, 2024

Author(s): Harsha Miriam Reji, Hemant S. Hegde, and R. Prabhu

We study the separability in multiqubit pure and mixed Greenberger-Horne-Zeilinger (GHZ) and W states with an accelerating qubit using the Abe-Rajagopal (AR) q-conditional entropy. We observe that the pure multiqubit GHZ and W states in the inertial-noninertial bipartition with one of their qubits a…

[Phys. Rev. A 110, 032403] Published Wed Sep 04, 2024

Author(s): John J. McCord, Shruti Dogra, and Gheorghe Sorin Paraoanu

The measurement and characterization of noise is a flourishing area of research in mesoscopic physics. In this work, we propose interaction-free measurements as a noise-detection technique, exploring two conceptually different schemes: the coherent and the projective realizations. These detectors co…

[Phys. Rev. A 110, 032404] Published Wed Sep 04, 2024

Author(s): Xin-Xin Yang, Bo-Hao Wu, Yu Chen, and Wei Zhang

The f-sum rules set general constraints on the response of a quantum many-body system to an external probe and hold significant relevance in the realm of various spectroscopy measurements. In practical conditions, a system unavoidably couples with the environment and acquires effective dissipation. …

[Phys. Rev. Lett. 133, 100401] Published Wed Sep 04, 2024

Author(s): Zehui Deng, Lu Liu, Wenan Guo, and Hai-Qing Lin

We study the scaling behavior of the Rényi entanglement entropy with smooth boundaries at the putative deconfined critical point separating the Néel antiferromagnetic and valence-bond-solid states of the two-dimensional J−Q3 model. We observe a subleading logarithmic term with a coefficient indicati…

[Phys. Rev. Lett. 133, 100402] Published Wed Sep 04, 2024

Author(s): Raymon S. Watson, Caleb Coleman, and Karen V. Kheruntsyan

For many-particle systems with short-range interactions, the local (same point) particle-particle pair correlation function represents a thermodynamic quantity that can be calculated using the Hellmann-Feynman theorem. Here we exploit this property to derive a thermodynamic Maxwell relation between …

[Phys. Rev. Lett. 133, 100403] Published Wed Sep 04, 2024

Author(s): Andrea Parlangeli

A new model of epidemics describes infections as part of a feedback loop—an approach that might one day help optimize interventions such as social distancing and lockdowns.

[Physics 17, 129] Published Wed Sep 04, 2024

Author(s): Michael Schirber

An analysis of gravitational data from the LIGO detector sets new limits on a wave-like form of dark matter called scalar-field dark matter.

[Physics 17, s101] Published Wed Sep 04, 2024

Author(s): Marric Stephens

A new method for preparing certain states on a quantum computer is predicted to take the same time regardless of the system size.

[Physics 17, s110] Published Wed Sep 04, 2024

Author(s): Jesús Rubio

The author introduces a closed-form class of optimal quantum measurements that exploit the symmetries of metrological platforms. This approach simplifies the practical search for optimal strategies and enhances resource allocation per measurement.

[Phys. Rev. A 110, L030401] Published Tue Sep 03, 2024

Author(s): Ivan Rojkov, Paul Moser Röggla, Martin Wagener, Moritz Fontboté-Schmidt, Stephan Welte, Jonathan Home, and Florentin Reiter

We present techniques for performing two-qubit gates on Gottesman-Kitaev-Preskill (GKP) codes with finite energy, and find that operations designed for ideal infinite-energy codes create undesired entanglement when applied to physically realistic states. We demonstrate that this can be mitigated usi…

[Phys. Rev. Lett. 133, 100601] Published Tue Sep 03, 2024