Nonlinear Physics

Researchers at the Institute for Molecular Science (NINS, Japan) and SOKENDAI have demonstrated a more than 2000% voltage-induced enhancement of near-field nonlinear optical responses. To achieve this giant modulation, they focused on an angstrom-scale gap formed between a metallic tip and substrate in a scanning tunneling microscope (STM), which can strongly confine and enhance light intensity through plasmon excitation. The paper is published in the journal Nature Communications.

Vacuum ultraviolet (VUV, 100–200 nm) light sources are indispensable for advanced spectroscopy, quantum research, and semiconductor lithography. Although second harmonic generation (SHG) using nonlinear optical (NLO) crystals is one of the simplest and most efficient methods for generating VUV light, the scarcity of suitable NLO crystals has long been a bottleneck.

Author(s): Zhao-Xian Chen, Yi Ru, Guang-Chen He, Ming-Hui Lu, Yan-Feng Chen, Yan-Qing Lu, and Ze-Guo ChenNonlinear coupling reshapes attractor landscapes to produce anomalous state transitions and full multistate excitation under adiabatic control. [Phys. Rev. Lett. 136, 037202] Published Tue Jan 20, 2026

Author(s): Kun Zhang, Qicheng Zhang, Shuaishuai Tong, Wenquan Wu, Xiling Feng, and Chunyin QiuExperiments with programmable electroacoustic cavities reveal that a multistable system can be steered into states that are unreachable with conventional control methods. [Phys. Rev. Lett. 136, 037201] Published Tue Jan 20, 2026

Researchers from Skoltech, MEPhI, and the Dukhov All-Russian Research Institute of Automation have proposed a new method to create compact gamma-ray sources that are simultaneously brighter, sharper, and capable of emitting multiple "colors" of gamma rays at once.

Scientists developed a reconfigurable topological photonic system that steers light in real time using optical pumping, enabling ultrafast adaptive control.

Author(s): Chance Ornelas-Skarin, Tatiana Bezriadina, Matthias Fuchs, Shambhu Ghimire, J. B. Hastings, Quynh L. Nguyen, Gilberto de la Peña, Takahiro Sato, Sharon Shwartz, Mariano Trigo, Diling Zhu, Daria Popova-Gorelova, and David A. ReisNonlinear x-ray diffraction is used to isolate the valence electron density in silicon, demonstrating a powerful imaging technique useful across a range of complex materials. [Phys. Rev. X 16, 011006] Published Wed Jan 07, 2026

Author(s): Khalid Musa, Santosh Kumar, Michael Katidis, and Yu-Ping HuangThis work demonstrates a photonic dense associative memory, which is important for high-capacity associative memory, combinatorial optimization, and computer vision. Here scalable, higher-order interactions beyond pairwise couplings would be key to progress. The authors use a spatial light modulator and second-harmonic generated light to implement both two- and four-body interactions. Four-body interactions are shown to increase storage capacity by a factor of 10 for uncorrelated patterns and a factor of up to 50 for correlated patterns, and to yield further benefits as well. These results point to a scalable route for energy-efficient, high-capacity optical neural networks. [Phys. Rev. Applied 25, 014011] Published Tue Jan 06, 2026

Author(s): Xue-Jin Zhang, Jin Cao, Lulu Xiong, Hui Wang, Shen Lai, Cong Xiao, and Shengyuan A. YangNonlinear thermoelectric responses provide a novel probe of valley physics. Here, the authors develop a theory for the intrinsic nonlinear valley Nernst effect, identify its quantum geometric origin in Berry connection polarizability dipole, demonstrate a generalized Mott relation to nonlinear Hall effect, and predict scaling law for nonlocal thermoelectric transport. These advances lay a foundational framework for nonlinear valley caloritronics. [Phys. Rev. B 112, 235430] Published Tue Dec 23, 2025

Imagine standing on top of a mountain. From this vantage point, we can see picturesque valleys and majestic ridges below, and streams wind their way downhill. If a drop of rain falls somewhere on this terrain, gravity guides it along a path until it settles in one of the valleys. The trajectory traced by this droplet is known as a flow line, a path that indicates the direction of movement determined by the landscape's gradient.

In January, a team led by Jim Schuck, professor of mechanical engineering at Columbia Engineering, developed a method for creating entangled photon pairs, a critical component of emerging quantum technologies, using a crystalline device just 3.4 micrometers thick.

Author(s): R. Y. Chu, L. Han, Z. H. Gong, X. Z. Fu, H. Bai, S. X. Liang, C. Chen, S-W. Cheong, Y. Y. Zhang, J. W. Liu, Y. Y. Wang, F. Pan, H. Z. Lu, and C. SongExperimental demonstration of the third-order nonlinear Hall effect in RuO 2 thin films provides a fingerprint for identifying altermagnets. [Phys. Rev. Lett. 135, 216703] Published Mon Nov 17, 2025

Nonlinear optical (NLO) materials play a vital role in modern photonic technology, driving advancements in applications such as laser frequency conversion, ultrafast optical switching, and quantum information processing. Among NLO crystals, borate-based systems have long remained at the forefront of short-wavelength (

Nonlinear optical dynamics—intensity-dependent response of light upon interaction with materials under high-intensity light sources—are of huge significance in modern photonics, finding applications in fields ranging from lasers, amplifiers, modulators, and sensors to the study of topics including quantum optics, nonlinear system dynamics, as well as light-matter interactions.

Author(s): Luca Dal Negro, Riccardo Franchi, and Marco OrnigottiThe authors demonstrate here the nonlinear optical response of epsilon-near-zero (ENZ) nanostructures at the single-photon level using fully nonperturbative quantum theory of open systems with indium tin oxide materials and Kerr-type nonlinearity. Closed-form analytical results obtained for spherical nanoparticles are numerically validated and extended to geometries that can be fabricated using state-of-the-art electron-beam lithography, establishing a rigorous benchmark for understanding quantum nonlinear effects in ENZ nanostructures with optical losses. These results are important to emerging quantum technology, including on-chip single-photon nondemolition detection, sensing, and spectroscopy. [Phys. Rev. B 112, 165433] Published Thu Oct 30, 2025

University of Queensland researchers have created a microscopic "ocean" on a silicon chip to miniaturize the study of wave dynamics. The device, made at UQ's School of Mathematics and Physics, uses a layer of superfluid helium only a few millionths of a millimeter thick on a chip smaller than a grain of rice.

Materials scientists can learn a lot about a sample material by shooting lasers at it. With nonlinear optical microscopy—a specialized imaging technique that looks for a change in the color of intense laser light—researchers can collect data on how the light interacts with the sample, and through time-consuming and sometimes expensive analyses, characterize the material's structure and other properties.

Author(s): Guangzhou Guo, Peng Wang, and Yu-Peng ZhangUltracompact objects have been recently found to be susceptible to a new nonlinear instability known as light-ring instability, triggered by stable light rings, thereby raising concerns about the viability of the compact objects as black hole alternatives. Here, the authors study a particular type of scalarized black holes, known to admit stable light rings and through rigorous numerical simulation, demonstrate the long-term stability of these objects, thereby showing that a stable light ring need not necessarily imply light-ring instability. [Phys. Rev. D 112, 084023] Published Thu Oct 09, 2025

Author(s): Yun-Wen Mao, Ilia Tutunnikov, Roman V. Krems, and Ilya Sh. AverbukhParametric perturbations of a Kerr oscillator are shown to induce persistent classical and quantum echoes in the dynamics of both coherent states and Schrödinger cat states. Quantum echoes are highly sensitive to the parameters of the cat states and can be recovered even when dissipation suppresses quantum revivals. [Phys. Rev. A 112, L040601] Published Wed Oct 08, 2025

Author(s): Loic Fache, François Copie, Pierre Suret, and Stéphane RandouxThe spectral properties of a soliton gas subject to weak gain and linear damping undergo significant changes due to dissipation. [Phys. Rev. Lett. 135, 157201] Published Wed Oct 08, 2025

Author(s): Tristan Pitre and Eric PoissonTidal deformations of neutron stars in binary inspiral leave an imprint on gravitational-wave emissions. Dynamical tides – in which the timescales of the tidal field and the internal hydrodynamics of neutron stars are comparable – display rich nonlinear phenomena only recently uncovered in the framework of Newtonian gravity. In this paper, an intrinsically general relativistic approach is developed eschewing the modal description of Newtonian theory. The nonlinearities of dynamical tides now find an inherently relativistic expression. [Phys. Rev. D 112, 084017] Published Tue Oct 07, 2025

Author(s): Jan-Magnus Christmann, Laura A. M. D’Angelo, Herbert De Gersem, Sven Pfeiffer, Sajjad H. Mirza, Matthias Thede, Alexander Aloev, and Holger SchlarbEfficiently simulating laminated magnets with fast excitation cycles is a long-standing challenge. Especially when a nonlinear magnetization curve must be considered, simulation times often become prohibitive. To address this problem, we introduce the homogenized harmonic balance finite element method (HomHBFEM), which combines a frequency-dependent homogenization of the yoke laminations with a harmonic balance method and thus drastically reduces the computational cost. Thereby, the HomHBFEM has allowed us, for the first time, to conduct nonlinear simulations of the fast orbit corrector magnets for the future light source PETRA IV at DESY. [Phys. Rev. Accel. Beams 28, 104601] Published Mon Oct 06, 2025

Over the past few years, engineers and material scientists have been trying to devise new optical systems in which light particles (i.e., photons) can move freely and in useful ways, irrespective of defects and imperfections. Topological phases, unique states of matter that are not defined by local properties, but by non-local and global features, can enable the robust movement of photons despite material defects.

Author(s): Jin Cao, Hui Wang, Shen Lai, Cong Xiao, and Shengyuan A. YangReciprocity of valley responses breaks down in nonlinear regime, challenging conventional wisdom. While the linear valley Hall effect and its inverse process have equal response coefficients per Onsager’s principle, nonlinear regimes reveal distinct symmetries and mechanisms. This study unveils a novel framework for nonlocal transport, introducing unique scaling laws as experimental signatures. These breakthroughs deepen nonlinear valleytronics, paving the way for innovative device applications and future explorations. [Phys. Rev. B 112, L121404] Published Thu Sep 18, 2025

Author(s): Jinyu Yao, Xinshu Zhang, Huawei Zhou, Xingyu Song, and Alessandro ToffoliWe develop a nonlinear wave reconstruction and prediction model with a dynamic averaging algorithm, in which shipborne radar images are used for data assimilation to improve the accuracy of wave reconstruction and prediction. Waves around the ship can be accurately predicted for the next few minutes under various sea states. Compared with the linear and second- order models, the new model includes the third-order nonlinear effects; thus, it significantly improves the prediction accuracy of extreme waves under rough sea states, providing effective safety guarantees for ship navigation and operations. [Phys. Rev. Fluids 10, 094801] Published Thu Sep 18, 2025

Author(s): Songyue Liu and Thomas C. O’ConnorAssociative polymer networks exhibit broad stretch fluctuations under elongational flow, leading to a rate-dependent viscosity. [Phys. Rev. Lett. 135, 098101] Published Thu Aug 28, 2025

Author(s): Ivan Sekulic, Ji Tong Wang, Jian Wei You, and Nicolae C. PanoiuThe problem of solving nonlinear scattering of optical waves from arbitrary distributions of particles becomes practically intractable when the number of particles is larger than just a few. Here, the authors introduce an approach based on multiple-scattering matrix theory that solves this problem for clusters of thousands of particles of arbitrary shape made of materials characterized by general frequency-dispersion relations, so that it describes the optical response of metallic, semiconductor, and polaritonic particles. To illustrate the versatility of the method, the enhancement of second-harmonic generation in a cluster of particles that supports bound-states in the continuum at both the fundamental frequency and second harmonic is demonstrated. [Phys. Rev. B 112, 035426] Published Mon

Synthetic antiferromagnets are carefully engineered magnetic materials made up of alternating ferromagnetic layers with oppositely aligned magnetic moments, separated by a non-magnetic spacer. These materials can display interesting magnetization patterns, characterized by swift changes in the behavior of magnetic moments in response to external forces, such as radio frequency (RF) currents.

The generation of electricity from heat, also known as thermoelectric energy conversion, has proved to be advantageous for various real-world applications. For instance, it proved useful for the generation of energy during space expeditions and military missions in difficult environments, as well as for the recovery of waste heat produced from industrial plants, power stations or even vehicles.

Many systems obey simple, linear rules: If you pull twice as hard on a spring, it stretches twice as far. However, when we introduce very large forces or complicated interactions, that linear rule breaks down into a "nonlinear" regime.

In a review just published in Nature Materials, researchers take aim at the oldest principle in electronics: Ohm's law.

Breaking inversion symmetry in materials allows deviations from Ohm's law, enabling nonlinear effects that could drive future nano- and quantum-electronic devices.

Author(s): Adam Anglart, Paweł Obrępalski, Agnès Maurel, Philippe Petitjeans, and Vincent PagneuxThe authors experimentally investigate here the Su-Schrieffer-Heeger model in a periodic water wave channel, observing robust topological edge modes consistent with theoretical predictions and 2D simulations. Remarkably, these sloshing modes localized at the boundaries persist under nonlinear excitation, where bifurcations and secondary resonances emerge. This work connects topological physics and fluid mechanics, providing an accessible platform for exploring wave localization, symmetry protection, and nonlinear dynamics in classical wave systems. [Phys. Rev. B 111, 224311] Published Mon Jun 30, 2025

Author(s): Weijian JiaoTo overcome the limitations of regular perturbation methods that fail to correctly capture some unusual nonlinear dispersion behaviors, the author proposes here an equivalent eigenvalue approach that converts the nonlinear wave equation to an equivalent linear eigenvalue problem. This directly gives the nonlinear dispersion relation and modal vectors. The theoretical approach is employed to 1D and 2D phononic crystals with alternating softening and hardening nonlinearities, revealing nonlinearity-induced band-gap opening and closing phenomena and achieving tunable frequency splitting and focusing effects. [Phys. Rev. B 111, 214308] Published Mon Jun 30, 2025

Author(s): A. Sud, K. Yamamoto, S. Iihama, K. Ishibashi, S. Fukami, H. Kurebayashi, and S. MizukamiApplying a strong enough radio frequency current to a synthetic antiferromagnet leads to nonlinear magnon-magnon coupling and Rabi-like splitting of the signal while preserving the symmetries of the system. [Phys. Rev. Lett. 134, 246704] Published Fri Jun 20, 2025

Author(s): Shulin Wang, Bing Wang, Chenyu Liu, Chengzhi Qin, Lange Zhao, Weiwei Liu, Stefano Longhi, and Peixiang LuA concept based on an exotic effect in periodic structures may be useful for developing future photonic devices. [Phys. Rev. Lett. 134, 243805] Published Fri Jun 20, 2025

Author(s): Clément Stahl, Denis Werth, and Vivian PoulinSharp features in the primordial power spectrum are a natural prediction of many UV-complete models of inflation. The authors use dedicated N-body simulations to demonstrate that features consistent with CMB constraints persist throughout the nonlinear regime of structure formation and thus may play a role in explaining tensions between the CMB and observations of the late-time matter distribution. While further numerical work is necessary to resolve the degeneracy with other effects, this study is a pioneering foundation for future research. [Phys. Rev. D 111, 123514] Published Tue Jun 10, 2025

Author(s): Alexander Wilzewski et al.A hypothetical fifth force could be detected by its effect on the optical transition frequencies of an element’s different isotopes. [Phys. Rev. Lett. 134, 233002] Published Tue Jun 10, 2025

Author(s): Octavio Albarrán, Renata Garcés, Giacomo Po, Christoph F. Schmidt, and Jeff D. EldredgeBacterial cell walls maintain integrity under high turgor pressure through a covalently linked peptidoglycan network. This study models the E . c o l i cell wall using a hyperelastic framework, suggesting that strain hardening underlies pressure-dependent stiffness and providing insights for further quantitative studies. #BiophysicsSpotlight #Interdisciplinary [Phys. Rev. E 111, 064405] Published Mon Jun 02, 2025

Author(s): Daniel P. Keane, Elnaz Nikoumanesh, Krutarth M. Kamani, Simon A. Rogers, and Ryan Poling-SkutvikFor a wide range of complex fluids, the transition from solid-like at rest to liquid-like when pushed can be predicted from properties of the at-rest state. [Phys. Rev. Lett. 134, 208202] Published Fri May 23, 2025

Researchers have long recognized that quantum communication systems would transmit quantum information more faithfully and be impervious to certain forms of error if nonlinear optical processes were used. However, past efforts at incorporating such processes could not operate with the extremely low light levels required for quantum communication.

Researchers have long recognized that quantum communication systems would transmit quantum information more faithfully and be impervious to certain forms of error if nonlinear optical processes were used. However, past efforts at incorporating such processes could not operate with the extremely low light levels required for quantum communication.

Author(s): Jörg Frauendiener, Chris Stevens, and Sebenele ThwalaFor the first time, a gravitational wave impinging onto a static black hole has been numerically simulated by including nonlinearity and with a computational domain from past to future null-infinity. [Phys. Rev. Lett. 134, 161401] Published Wed Apr 23, 2025

Researchers developed a scalable fabrication process using soft nanoimprint lithography to create lithium niobate metalenses, enabling efficient nonlinear optics through enhanced second-harmonic generation

Author(s): S. Mirzaei-Ghormish and Ryan M. Camacho, the light-induced self-organization of particles, is essential in levitated optomechanics, nanomaterials, and quantum optics. Conventional models are limited to linear optical interactions, though, and lack tunable mechanisms for trap stabilization or reconfiguration that do not involve moving the optical fields themselves. This work develops a theory of nonlinear optical binding that produces surprising equilibrium configurations, tunable trap periodicities, and enhanced stability at subwavelength separations, with no beam shaping or external fields. These results may provide a concrete pathway for power-controlled particle assembly and programmable optical matter. [Phys. Rev. Applied 23, 044044] Published Mon Apr 21, 2025

Neural networks are one typical structure on which artificial intelligence can be based. The term neural describes their learning ability, which to some extent mimics the functioning of neurons in our brains. To be able to work, several key ingredients are required: one of them is an activation function which introduces nonlinearity into the structure. A photonic activation function has important advantages for the implementation of optical neural networks based on light propagation. Researchers have now experimentally shown an all-optically controlled activation function based on traveling sound waves. It is suitable for a wide range of optical neural network approaches and allows operation in the so-called synthetic frequency dimension.

Author(s): Yu-jiang Dong, Xinghao Wang, Jianmin Zheng, Weiliang Qiao, Rui-Rui Du, Loren N. Pfeiffer, Kenneth W. West, and Kirk W. BaldwinNonlinear transport studies are performed to investigate the low-temperature behavior of a CF-2 Wigner solid surrounded by fractional quantum Hall liquid. The electric-field-temperature duality phenomenon of a Wigner solid was observed, which is interpreted within the Berezinskii-Kosterlitz-Thouless phase transition model. [Phys. Rev. Research 7, L022011] Published Wed Apr 09, 2025

Author(s): Xu Zheng and Y. D. ChongA rigorous analysis of noise–nonlinearity interplay at exceptional points reveals new challenges for non-Hermitian sensing. [Phys. Rev. Lett. 134, 133801] Published Thu Apr 03, 2025

A research team from the Xinjiang Technical Institute of Physics and Chemistry of the Chinese Academy of Sciences has made strides in the theoretical design of nonlinear optical (NLO) materials by leveraging machine learning techniques. The team introduced a new strategy to explore uncharted chemical spaces, enabling the quantitative prediction of second harmonic generation (SHG) coefficients for complex NLO systems spanning infrared to deep ultraviolet wavelengths.

The El Niño-Southern Oscillation (ENSO), the most prominent interannual climate variability signal, has been widely studied for its teleconnections with Antarctic sea ice variability. However, its influence on the predictability of Antarctic sea ice remains poorly understood, hindering the development of accurate sea ice prediction models.

Author(s): Angelo Caravano, Gabriele Franciolini, and Sébastien Renaux-PetelScenarios like u l t r a s l o w − r o l l Inflation significantly change the final stages of slow-roll inflation to create large curvature perturbations that produce gravitational waves (GW) and primordial black holes (PBH). These phases are outside the usual

Author(s): Francesca Mignacco, Chi-Ning Chou, and SueYeon ChungDespite progress in artificial intelligence and neuroscience, the theoretical understanding of how neural networks learn complex functions remains sparse. One promising avenue involves analyzing the geometric properties of network representations, i.e., the activity of neural populations, and their impact on task performance using statistical physics methods. Existing approaches have been restricted to linear probes. The authors overcome this limitation by proposing a theoretical framework to address non-linearly-separable representations leveraging contextual information, a ubiquitous paradigm in brain computation. The findings allow for future investigations into high-dimensional representation efficiency and analyses of biological and artificial datasets, promising relevant implications for

Researchers from Oakland University have made a significant breakthrough in the field of optical materials, unveiling the exceptional capabilities of Ba₃(ZnB₅O₁₀)PO₄ (BZBP). Although this transparent crystal closely resembles ordinary window glass, it exhibits extraordinary properties that set it apart from others.

A team of researchers has identified a unique phenomenon, a "skin effect," in the nonlinear optical responses of antiferromagnetic materials. The research, published in Physical Review Letters, provides new insights into the properties of these materials and their potential applications in advanced technologies.

Nonlinear dynamical systems are systems that can undergo sudden shifts not due to changes in their state or stability, but in response to the rate at which external conditions or parameters change. These sudden shifts, known as noise-induced and rate-induced tipping, can make predicting how the systems will shift over time more challenging.

Author(s): Abigail Postlewaite, Arpit Raj, Swati Chaudhary, and Gregory A. FieteMultilayered graphene systems provide a highly tunable platform to study quantum geometric effects. Here, the authors show that the quantum geometry of electronic bands in rhombohedral trilayer graphene leads to a large shift-current response which can be tuned by applying a displacement field perpendicular to the layers. The authors compare the response with Bernal stacked bilayer graphene and find additional features arising due to the confluence of quantum geometry and the multiband nature of rhombohedral trilayer graphene. [Phys. Rev. B 110, 245122] Published Tue Dec 10, 2024

Author(s): Valerio Lucarini and Mickaël D. ChekrounResponse theory for nonequilibrium systems provides a basis for optimal fingerprinting in climate system, a framework crucial for linking climate change to both anthropogenic and natural drivers. [Phys. Rev. Lett. 133, 244201] Published Mon Dec 09, 2024

Author(s): K. Dini, H. Sigurðsson, N. W. E. Seet, P. M. Walker, and T. C. H. LiewPolariton neurons allow exciton-polaritons to transport information using a successive local switching in analogy to action potentials in biological neurons. The authors show here an analogue of saltatory conduction for enhancing signal speeds: by connecting bistable nodes with waveguides, polariton signal speeds can be increased tenfold. The modeling of this system requires a new theoretical tool: nonlinear finite-difference time-domain simulation, which accounts for the propagation of light in the full three-dimensional nanostructure together with nonlinear exciton-exciton scattering using Maxwell-Bloch equations. [Phys. Rev. B 110, 214303] Published Wed Dec 04, 2024

Author(s): Yao-Jui Chan, Syed Mohammed Faizanuddin, Raju Kalaivanan, Sankar Raman, Hsin Lin, Uddipta Kar, Akhilesh Kr. Singh, Wei-Li Lee, Ranganayakulu K. Vankayala, Min-Nan Ou, and Yu-Chieh WenNonlinear photocurrents in topological semimetals encode quantum geometric characters of Bloch wavefunctions and band topology, and offer a new opportunity for advanced photovoltaics. Here, the authors characterize the nonlinear photoconductivities of chiral multifold semimetal CoSi through a refined terahertz emission spectroscopy analysis. The results reveal a large linear shift conductivity and confirm a giant nonquantized circular injection conductivity in the mid-infrared range. Bulk transverse injection currents and relatively weak photon drag effect are also identified. [Phys. Rev. B 110, L201118] Published Tue Nov 26, 2024

A team of researchers has successfully demonstrated nonlinear Compton scattering (NCS) between an ultra-relativistic electron beam and an ultrahigh intensity laser pulse using the 4-Petawatt laser. The innovative approach was the usage of only a laser for electron-photon collisions, in which a multi-PW laser is applied both for particle acceleration and for collision (also called an all-optical setup). This achievement represents a significant milestone in strong field physics, in particular strong field quantum electrodynamics (QED), offering new insights into high-energy electron-photon interactions without the need for a traditional mile-long particle accelerator.

A team of researchers has successfully demonstrated nonlinear Compton scattering (NCS) between an ultra-relativistic electron beam and an ultrahigh intensity laser pulse using the 4-Petawatt laser at the Center for Relativistic Laser Science (CoReLS) within the Institute for Basic Science at Gwangju Institute of Science and Technology (GIST), Korea.

Author(s): Debottam Mandal, Sanjay Sarkar, Kamal Das, and Amit AgarwalThe authors develop here a comprehensive framework for third-order electronic transport, focusing on the impact of quantum geometry in materials where conventional responses are absent. By deriving new forms of reciprocal longitudinal and Hall currents in time-reversal symmetry-broken systems, they reveal how quantum geometric features – specifically, the quantum geometric connection and tensor – shape these nonlinear currents. This theoretical advancement provides a blueprint for identifying materials with intrinsic third-order responses, with potential applications in advanced quantum technologies. [Phys. Rev. B 110, 195131] Published Wed Nov 13, 2024

Author(s): Alberto Nardin, Daniele De Bernardis, Rifat Onur Umucalılar, Leonardo Mazza, Matteo Rizzi, and Iacopo CarusottoNonlinear chiral Luttinger liquid theory is able to describe the dynamics of a fractional quantum Hall fluid even on the small lattices that are available to experiments. [Phys. Rev. Lett. 133, 183401] Published Tue Oct 29, 2024

Author(s): Hanxu Zhang, Tao Li, and Xu WangHydrogenlike thorium-229 ions interacting with intense lasers could unlock a highly nonlinear and nonperturbative regime of light-nucleus interaction. [Phys. Rev. Lett. 133, 152503] Published Fri Oct 11, 2024

In recent years, many physicists and materials scientists have been studying a newly uncovered class of magnetic materials known as altermagnets. These materials exhibit a unique type of magnetism that differs from both conventional ferromagnetism and antiferromagnetism, marked by electrons whose spin varies depending on their momentum.

A recent study has unveiled a transformative nonlinear optical metasurface technology. This new technology, characterized by structures smaller than the wavelength of light, paves the way for significant advancements in next-generation communication technologies, including quantum light sources and medical diagnostic devices.

Author(s): Diego García Ovalle, Armando Pezo, and Aurélien ManchonThe optical Kerr effect, widely used for probing magnetic domains, can be used to detect nonequilibrium orbital accumulation, even in the absence of spin-orbit coupling. In certain low-symmetry crystals, this orbital accumulation is associated with a nonlinear Hall effect that can be exploited for terahertz (THz) detection. As a result, the “orbital” Kerr effect is directly related to the THz responsivity of the material. Using first-principles calculations, the authors demonstrate here that this effect in low-symmetry crystals and multilayers can be remarkably large. [Phys. Rev. B 110, 094439] Published Thu Sep 26, 2024

A research team has discovered significant nonlinear Hall and wireless rectification effects at room temperature in elemental semiconductor tellurium (Te). Their research is published in Nature Communications.

Author(s): Sopheak Sorn and Adarsh S. PatriDiscovering long-range hidden orders is a long-standing challenge in the field of unconventional magnetism. Such type of order is elusive to conventional magnetic probes. Here, focusing on the archetypal ferro-octupolar ordering in metallic heavy-fermion compounds, the authors demonstrate through a combination of semiclassical transport and general symmetry analysis that nonlinear Hall transport is the dominant experimental signature. [Phys. Rev. B 110, 125127] Published Wed Sep 11, 2024

Author(s): Emily Z. Zhang, Ciarán Hickey, and Yong Baek KimTwo-dimensional coherent spectroscopy ( 2 D C S ) has emerged as a powerful tool for probing nonlinear excitation dynamics in quantum magnets, overcoming the limitations of traditional inelastic neutron scattering as a linear probe. The authors use here classical molecular dynamics simulations to compare the 2 D C S responses of various models with large Kitaev interactions, revealing distinct features between quantum spin liquids, classical spin liquids, and

Author(s): Yuan Fang, Jennifer Cano, and Sayed Ali Akbar GhorashiInvestigation of the nonlinear response in altermagnets uncovers the role of quantum geometry order by order. [Phys. Rev. Lett. 133, 106701] Published Thu Sep 05, 2024

Author(s): Marric StephensResearchers 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): Jonathan Colen, Alexis Poncet, Denis Bartolo, and Vincenzo VitelliA clever use of machine learning guides researchers to a missing term that’s needed to accurately describe the dynamics of a complex fluid system. [Phys. Rev. Lett. 133, 107301] Published Tue Sep 03, 2024

Author(s): Rui Chen, Z. Z. Du, Hai-Peng Sun, Hai-Zhou Lu, and X. C. XieThe nonlinear Hall effect provides a new experimental tool to probe the condensed matter phases. This work presents the first real-space lattice theory of the nonlinear Hall effect, so that strong disorder can be handled to explain an unexpected fluctuation in the experiments and discover a “localization” of the nonlinear Hall effect. The calculation can be generalized to more crystal lattices. [Phys. Rev. B 110, L081301] Published Tue Aug 20, 2024

Author(s): Alexander Frenett, Zack Lasner, Lan Cheng, and John M. DoyleThe authors explore candidates for a next-generation search for the electron electric dipole moment (eEDM) by experimentally measuring the vibrational loss channels in three Sr-containing nonlinear molecules. They conclude that SrNH 2  is the optimal choice for a future laser-cooled molecule-based eEDM experiment. [Phys. Rev. A 110, 022811] Published Wed Aug 14, 2024

In recent research, a scientist from Princeton University has performed the first nonlinear study of the merger of a black hole mimicker, aiming to understand the nature of gravitational wave signals emitted by these objects, which could potentially help to identify black holes more accurately.

A research team led by Dr. Li Yunlong at the Shenzhen Institute of Advanced Technology (SIAT) of the Chinese Academy of Sciences delved into the origins of nonlinear current response in polycrystalline metal halide perovskite X-ray detectors. Their study was published in ACS Applied Materials & Interfaces on July 14.

Using two optically-trapped glass nanoparticles, researchers observed a novel collective Non-Hermitian and non-linear dynamic driven by non-reciprocal interactions. This contribution expands traditional optical levitation with tweezer arrays by incorporating non-conservative interactions.

UCLA researchers have conducted an in-depth analysis of nonlinear information encoding strategies for diffractive optical processors, offering new insights into their performance and utility. Their study, published in Light: Science & Applications, compared simpler-to-implement nonlinear encoding strategies that involve phase encoding with the performance of data repetition-based nonlinear information encoding methods, shedding light on their advantages and limitations in the optical processing of visual information.

Structured light can significantly enhance information capacity, due to its coupling of spatial dimensions and multiple degrees of freedom. In recent years, the combination of structured light patterns with image processing and machine intelligence has shown vigorous development potential in fields such as communication and detection.

Scientists face many tradeoffs when trying to build and scale up brain-like systems that can perform machine learning.

Author(s): Bethany Clarke, Yongyun Hwang, and Eric E. KeavenyThe follower force model is a fundamental model for active filaments, commonly utilized to model microtubule-motor protein complexes and collections of cilia. In this work we perform a thorough analysis of this model, employing techniques from computational dynamical systems, adapted from high Reynolds number fluid dynamics, to map out the bifurcations in the system and classify emergent states. This approach allows us to bridge the gap between 2D and 3D analyses, in particular establishing the initial buckling as a double Hopf bifurcation. Additionally, we identify the existence of a quasiperiodic solution at the second bifurcation, and categorize the dynamics at higher values of forcing. [Phys. Rev. Fluids 9, 073101] Published Mon Jul 15, 2024

Nonlinear optics is a branch of optics that deals with the complex nonlinear relationships between the optical response of the medium and the incident light when it interacts with the optical medium. Currently, nonlinear optics has been successfully applied to a variety of fields, such as laser modulation, optical signal processing, and medical imaging.

Photochromic compounds, which change their color when exposed to light, have been widely used as photo switches to control different properties of materials. Nonlinear photochromic compounds, characterized by a nonlinear response to the intensity of incident light, have attracted special attention among researchers as the nonlinearity leads to enhanced contrast and improved spatial resolution in photochromic reactions.

Author(s): Arkady Kurnosov, Lucas J. Fernández-Alcázar, Alba Ramos, Boris Shapiro, and Tsampikos KottosA universal, one-parameter scaling theory is developed that describes transport behavior from the ballistic to the diffusive regime in multimode nonlinear photonic circuits. [Phys. Rev. Lett. 132, 193802] Published Wed May 08, 2024

Author(s): Lukas A. Jakob, William M. Deacon, Rakesh Arul, Bart de Nijs, Niclas S. Mueller, and Jeremy J. BaumbergMolecular vibrations play a key role in sensing, catalysis, molecular electronics and beyond, but investigating the coherence and dynamics of individual molecules is extremely challenging. Here, the authors study the vibrational dynamics of ~100 molecules confined in plasmonic nanocavities through simultaneous coherent and incoherent Raman scattering to access both phonon population decay and dephasing. The results show that the dephasing of collective molecular vibrations is accelerated by excitation-power-dependent processes, amplified by the plasmonic near-field enhancement in the cavity. [Phys. Rev. B 109, 195404] Published Thu May 02, 2024

Author(s): Mojtaba Rajabi, Taras Turiv, Bing-Xiang Li, Hend Baza, Dmitry Golovaty, and Oleg D. LavrentovichElectrophoretic transport is greatly enhanced in a nematic environment due to shear thinning. [Phys. Rev. Lett. 132, 158102] Published Thu Apr 11, 2024

Light can compute functions during its propagation and interaction with structured materials, with high speed and low energy consumption. Achieving universal computing using all-optical neural networks requires optical activation layers with nonlinear dependence on input. However, the existing optical nonlinear materials are either slow or have very weak nonlinearity under the natural light intensity levels captured by a camera. Therefore, the design and development of new optical activation functions is essential for realizing optical neural networks that compute with ambient light.

Author(s): Hugh Morison, Jagmeet Singh, Nayem Al Kayed, A. Aadhi, Maryam Moridsadat, Marcus Tamura, Alexander N. Tait, and Bhavin J. ShastriRecurrent neural networks based on silicon photonics can take on a wide range of dynamical features at high bandwidth, but experimental demonstrations are being held back by of the lack of a physical-level simulation platform that accounts for parasitic effects. This study uses photonic Verilog-A models to demonstrate characteristic neural dynamics. Simulation reveals that these dynamics exhibit a topological equivalence to the continuous-time recurrent-neural-network model. [Phys. Rev. Applied 21, 034013] Published Fri Mar 08, 2024

Author(s): Lujunyu Wang, Jiaojiao Zhu, Haiyun Chen, Hui Wang, Jinjin Liu, Yue-Xin Huang, Bingyan Jiang, Jiaji Zhao, Hengjie Shi, Guang Tian, Haoyu Wang, Yugui Yao, Dapeng Yu, Zhiwei Wang, Cong Xiao, Shengyuan A. Yang, and Xiaosong WuResearchers have observed a new class of nonlinear Hall effect that can be understood through a geometric description of the electronic wave function. [Phys. Rev. Lett. 132, 106601] Published Wed Mar 06, 2024

A research team from the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) and the University of Salerno in Italy has discovered that thin films of elemental bismuth exhibit the so-called non-linear Hall effect, which could be applied in technologies for the controlled use of terahertz high-frequency signals on electronic chips.

Glass can be synthesized through a novel "crystal-liquid-glass" phase transformation. Crystalline materials can be fine-tuned for desired properties such as improved mass transfer and optical properties through coordination chemistry and grid chemistry design principles.

Author(s): H. Handa, Y. Okamura, R. Yoshimi, A. Tsukazaki, K. S. Takahashi, Y. Tokura, and Y. TakahashiRecent advances in high-field terahertz technologies can unveil the nonlinear response of elementary excitations. This work finds large-amplitude coherent phonon dynamics in the fully anharmonic regime by intense terahertz excitation of the ferroelectric semiconductor In-doped (Sn,Pb)Te. The high-field resonant drive of soft phonons induces the dramatic shift of transient phonon frequency near the ferroelectric transition point. This highly nonlinear terahertz response quantitatively reveals a phonon potential dominated by strong anharmonicity and temporal lattice dynamics with giant atomic displacement. [Phys. Rev. B 109, L081102] Published Fri Feb 02, 2024

Nature is the foremost international weekly scientific journal in the world and is the flagship journal for Nature Portfolio. It publishes the finest peer-reviewed research in all fields of science and technology on the basis of its originality, importance, interdisciplinary interest, timeliness, accessibility, elegance and surprising conclusions. Nature publishes landmark papers, award winning news, leading comment and expert opinion on important, topical scientific news and events that enable readers to share the latest discoveries in science and evolve the discussion amongst the global scientific community.

Author(s): A. O. Scheie, Y. Kamiya, Hao Zhang, Sangyun Lee, A. J. Woods, M. O. Ajeesh, M. G. Gonzalez, B. Bernu, J. W. Villanova, J. Xing, Q. Huang, Qingming Zhang, Jie Ma, Eun Sang Choi, D. M. Pajerowski, Haidong Zhou, A. S. Sefat, S. Okamoto, T. Berlijn, L. Messio, R. Movshovich, C. D. Batista, and D. A. TennantQuantum spin liquids were proposed over 50 years ago, but identifying experimental signatures is extremely difficult. Here, the authors study the Yb triangular materials KYbSe 2 and NaYbSe 2 , and show that KYbSe 2 is well described