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  • Extending the spectral range of on-chip tunable Raman laser is challenging due to the limited Raman frequency shifts and pump tuning bandwidth. The authors combine the dispersion engineering of thin film lithium niobate with cascaded Raman lasing to realize a widely tunable laser with 335-nm spectral extension and sub-milliwatt threshold.

    • Yanjing Zhao
    • Xiaoyue Liu
    • Minhao Pu
    ArticleOpen Access
  • Polarization, or a division into mutually hostile groups, is a common feature of social systems and is studied in terms of the structural balance of semicycles in signed networks. The authors propose a computationally efficient framework for multiscale analysis of structural balance based on semiwalk approximations applicable to any simple signed network.

    • Szymon Talaga
    • Massimo Stella
    • Andreia Sofia Teixeira
    ArticleOpen Access
  • While Majorana excitations are often considered to be a cornerstone for proposed quantum devices, their experimental detection has proven to be a significant challenge. Here, the authors theoretically and experimentally demonstrate that the Kitaev candidate material Ag3LiIr2O6 may support a Majorana-Fermi surface, which could potentially serve as a “smoking gun” for a quantum spin liquid ground state through the lens of specific heat data.

    • Joshuah T. Heath
    • Faranak Bahrami
    • Kevin Bedell
    ArticleOpen Access
  • Higher-order topological phase appears as a pioneering topic, and together with the non-Hermiticity, brings broad attentions recently. The authors explore the interplay between the non-Hermiticity and hierarchical topological states in a non-reciprocal framework and show the flexible reconstruction of non-Hermitian higher-order topological states.

    • Hongfei Wang
    • Biye Xie
    • Wei Ren
    ArticleOpen Access
  • The emergence of large intrinsic anomalous Hall effect (AHE) is tied to the Berry curvature in magnetic topological semimetals, but other alternatives to achieve AHE are still desirable. The authors show that a half-topological semimetal state provides an alternative platform for driving AHE and exhibits a nearly isotropic negative magnetoresistance.

    • Yanglin Zhu
    • Cheng-Yi Huang
    • Zhiqiang Mao
    ArticleOpen Access
  • Driving a quantum material from trivial to non-trivial topological phase can be engineered, for instance, by an applied external field but understanding the physics of the transition can be complex. Here, the authors report a pressure-induced topological phase transition from a semiconductor to a Weyl semimetal phase in 2D Te, and investigate the underlying dynamics using a range of magneto-transport techniques.

    • Chang Niu
    • Zhuocheng Zhang
    • Peide D. Ye
    ArticleOpen Access
  • The authors present a series of correlated insulating states of twisted bilayer graphene that is detected using an atomic force microscope tip. An additional experiment demonstrates the coupling of a mechanical oscillator to a quantum device.

    • Alexina Ollier
    • Marcin Kisiel
    • Ernst Meyer
    ArticleOpen Access
  • The sign of switching currents in supercurrent diodes depends on their flow direction, however effective strategies to control it in single platforms with large efficiency are missing. The authors realise a supercurrent diode in superconducting weak links that is tunable both in amplitude and sign of switching current by an out of-plane magnetic field in a regime without magnetic screening.

    • Daniel Margineda
    • Alessandro Crippa
    • Francesco Giazotto
    ArticleOpen Access
  • Highly-directional hyperbolic surface plasmons are widely exploited in optoelectronic devices, but obtaining the same performance in simpler platforms over metahyperbolic surfaces has technological advantages for integration. The authors predict that RuOCl2 monolayers exhibit low-loss hyperbolic responses across the THz to UV spectral range.

    • Han Gao
    • Xuejin Zhang
    • Mingwen Zhao
    ArticleOpen Access
  • The recent discovery of superconductivity in the nickelates provides another angle to investigate this phenomenon in the high-Tc cuprates and hopefully help solve the mechanism of their unconventional superconductivity. Here, the authors report an increase in Tc for Pr0.8Sr0.2NiO2 where strain from the underlying LSAT substrate plays a possible role, supporting simulations also reveal the contributing role Ni and O orbitals hybridisation play in the unconventional pairing.

    • Xiaolin Ren
    • Jiarui Li
    • Zhihai Zhu
    ArticleOpen Access
  • Changes in the underlying dynamics of an observed system manifest as deformation in the underlying attractor in phase space. We propose a method to construct a discretised network representation of the attractor and demonstrate its applicability in identifying dynamical change points in various theoretical and real systems.

    • Eugene Tan
    • Shannon D. Algar
    • Michael Small
    ArticleOpen Access
  • Coherent microwave-to-optical conversion is crucial for networking physically separated quantum devices. This paper demonstrates coherent conversion of microwaves to a wide, tuneable optical frequency range using room-temperature Rb atoms, supporting frequency division multiplexing and coherent frequency channel control.

    • Benjamin D. Smith
    • Bahar Babaei
    • Lindsay J. LeBlanc
    ArticleOpen Access
  • This paper theoretically predicts near-unity efficiency in converting a guided mode to free space radiation via a deep-subwavelength metallic hole. This phenomenon is enabled by a topologically protected one-way waveguide mode, where reciprocity is broken through an external magnetic field at terahertz frequencies.

    • Jie Xu
    • Yamei Luo
    • Kosmas L. Tsakmakidis
    ArticleOpen Access
  • Non-orthogonal quantum states cannot be perfectly distinguished - a fact of central importance in quantum mechanics, from both a fundamental and practical viewpoint. The authors introduce an approach to this problem, using entangled measurements to distinguish quantum states better than what is possible with direct measurements.

    • Lorcán O. Conlon
    • Falk Eilenberger
    • Syed M. Assad
    ArticleOpen Access
  • Platicon microcombs in the normal-dispersion regime exhibit asymmetric spectral features because it largely relies on asymmetric local dispersion anomalies. The authors demonstrate stable, power-efficient microcombs with high spectral symmetry by means of symmetrical dispersion engineering.

    • Jiaqi Li
    • Yanfeng Zhang
    • Siyuan Yu
    ArticleOpen Access
  • The conventional methods to break reciprocity in the microwaves involve bulky magnets and complex spatial-temporal modulation, impairing the development in modern compact electronic systems. To circumvent this problem, the authors realize a lightweight, integrable, and all-passive metasurface that enables nonreciprocal transmission.

    • Xiaozhen Yang
    • Erda Wen
    • Daniel Sievenpiper
    ArticleOpen Access
  • Topological insulators are bulk insulators with conducting zero-energy edge states conventionally predicted by topological indices, such as winding numbers in one-dimensional lattices. Here, the authors use the Jackiw-Rebbi theory to reveal that the number of topologically protected zero-energy states can be higher than the winding number.

    • Amir Rajabpoor Alisepahi
    • Siddhartha Sarkar
    • Jihong Ma
    ArticleOpen Access
  • Environmental factors such as mechanical stresses govern the cellular behavior and physiology, but the role of selfinduced biomechanical stresses in growing bacterial colonies is still unclear. The authors reveal how the response to collective mechanical forces acting on the individual cells regulates the size of growing bacteria.

    • René Wittmann
    • G. H. Philipp Nguyen
    • Anupam Sengupta
    ArticleOpen Access
  • The mechanical response of polymer films is affected by size effects under nanoconfinement, but the mechanism of such response in terms of molecular configurations and chain conformations has proven elusive. The authors reveal the conformational origin of the stiffening behavior in crosslinked polymeric nanofilms via simulations and experiments.

    • Zhengyang Zhang
    • Pei Bai
    • Yanming Wang
    ArticleOpen Access
  • The narrow escape theory (NET) predicts the escape time distribution of Brownian particles confined to a domain with reflecting borders except for one small window. We systematically tested the NET in a disc both experimentally as well as with stochastic numerical simulations and found excellent agreement with theory.

    • Elisabeth Meiser
    • Reza Mohammadi
    • Susanne F. Fenz
    ArticleOpen Access