Advanced Physics Research最新文献

Magnetic Solitons Appear in 3D Interconnected Nanohelices

A new study shows how magnetic domain walls and linked vortex-anti-vortex pairs can form in 3D nanowire arrays formed of interconnected helices. In Research Article e00135, Charudatta Phatak and co-workers show how 3D geometric design can control both the solitons that form and the magnetization switching pathway. Demonstration of this highly tunable system shows the potential for using 3D nanomagnets for applications in data storage, unconventional computing, and sensing. The cover image shows an experimental magnetic induction map of a 3D nanowire array obtained through Lorentz transmission electron microscopy.

Low-Temperature Ferroelectric Properties in HZO Capacitors

The study by Flavien Berthaud and co-workers highlights the potential of HZO ferroelectric capacitors for low-temperature applications. A new electrical characterization method to isolate domain switching is presented in Research Article e00127; it reveals a two step switching mechanism that causes the pinched hysteresis at room temperature.

Solar-blind ultraviolet (UV) photodetectors operating within the wavelength range of 200–280 nm have attracted considerable interest owing to their vital applications in missile warning, flame sensing, space communication, and environmental monitoring. Conventional solar-blind photodetectors based on three-dimensional (3D) wide-bandgap semiconductors are often limited by complex fabrication processes, high cost, and intrinsic rigidity. The emergence of two-dimensional (2D) materials offers a promising alternative, capitalizing on their distinctive properties such as strong light-matter interactions, tunable bandgaps, excellent flexibility, and the ability to construct van der Waals heterostructures free from lattice-matching constraints. This review provides a comprehensive summary of recent advances in solar-blind UV photodetectors based on 2D materials and their heterostructures. First, the fundamental mechanisms and performance metrics of photodetectors are described. Subsequently, a detailed overview of recent progress in devices fabricated from various 2D materials is presented, including layered materials (e.g., hexagonal boron nitride, transition metal dichalcogenides, metal thio/selenophosphates, bismuth oxyhalides), novel materials (e.g., metal oxides and perovskites), and mixed-dimensional heterostructures (2D/3D heterostructures). Finally, the review addresses the remaining challenges and suggests prospective research directions, highlighting the potential of 2D materials in enabling the next generation of high-performance, flexible, and miniaturized solar-blind.

This work develops and rigorously analyzes reduced-order modeling (ROM) techniques for the time-dependent Schrödinger equation (TDSE), with the goal of efficiently capturing essential quantum dynamics at significantly reduced computational cost. Three major ROM frameworks–Proper Orthogonal Decomposition (POD), Dynamic Mode Decomposition (DMD), and Reduced Basis Methods (RBM) are explored and compared–in the context of quantum wavefunction evolution. Comprehensive mathematical formulations are presented, including projection-based Galerkin approximations, a priori and a posteriori error estimates, stability analyses, and convergence guarantees. Numerical experiments are conducted for canonical quantum systems such as the infinite square well, harmonic oscillator, and tunneling through potential barriers, as well as a time-dependent controlled two-level system. It is demonstrated that ROMs can achieve orders-of-magnitude dimensionality reduction while maintaining high fidelity with full-order model (FOM) solutions. Furthermore, the framework is extended to higher-dimensional problems, nonlinear potentials, and multi-particle systems, with applications in quantum control and entanglement dynamics. Visualization of ROM accuracy through mesh, surface, and isosurface plots, as well as convergence studies, confirms the robustness of the proposed methods. To support reproducibility and further research, all MATLAB code used to generate the numerical experiments is made publicly available via GitHub. These results establish ROM as a powerful tool for real-time simulation, control, and optimization in computational quantum mechanics.

In this work, a quantum bound is derived for the efficiency of a heat engine operating with two-level quantum systems as the working substance. This bound is found by using the extension of the monotonicity of quantum relative entropy in terms of Petz recovery maps.

In optics, temporal mirrors can be realized using solitons - stable refractive index barriers propagating at the speed of light that can be probed by weak waves reflecting off the barrier. This approach offers an alternative method for achieving temporal analogues of reflection.Unlike time-varying material approaches, temporal reflection in soliton-based propagation models has already been demonstrated experimentally. This mechanism exists across different physical systems, enabling laboratory investigations of otherwise inaccessible phenomena such as event horizon physics, rogue wave dynamics, and negative mass effects. This capability to simulate extreme physical conditions makes the approach particularly valuable for advancing efficient light-matter interactions in optical technologies and modern photonics. While such optical temporal mirrors are experimentally feasible, existing implementations face significant technical challenges: they require the generation of femtosecond pulses at precisely tuned incommensurate frequencies. Here, we demonstrate a practical scheme that inherently generates a temporal mirror over extended propagation distances, with back-reaction continuously modifying the conditions required to sustain the mirror. This process autonomously generates both the soliton and test wave at precisely controlled positions in time, space, and frequency. Our scheme provides access to intriguing physics phenomena using modest resources available in standard optical laboratories, leveraging well-established optical effects.

Diel vertical migration (DVM) is the daily movement of motile phytoplankton between light-rich surface waters and deeper nutrient-rich layers, typically governed by internal clocks. However, many species show irregular patterns that deviate from expected circadian rhythms. Studying Heterosigma akashiwo, a bloom-forming phytoplankton, we found that cells regulate their vertical movement by modulating local pH, affecting their gravitactic behavior. This self-regulation creates sub-populations that are physiologically similar but differ in behavior, remaining vertically separated even in uniform environments. These sub-populations had similar swimming speeds, growth, and photosynthetic activity, suggesting stable co-existence rather than environmental differences. Remarkably, vertical separation reappeared when each group was exposed to the other's spent media—an effect not seen with their own. Modeling and imaging showed that these chemical cues subtly alter cell shape, influencing gravitactic stability. Further experiments confirmed that pH shifts, consistent with those in the spent media, could replicate these behavioral changes. Together with nighttime data, results support a circadian model where diurnal pH regulation drives gravitactic divergence. This chemically mediated migration may enhance ecological fitness by promoting division of labor across the day-night cycle and could refine models of phytoplankton behavior, circadian, diel vertical migration, gravitaxis, microswimmers, modelling, pH particularly in the context of ocean acidification.

Non-collinear magnetism is of high interest in the field of magnetoelectrics supplying a convenient mechanism to break inversion symmetry and thereby allowing for a spontaneous electrical polarization. Such “multiferroics of spin origin” are inherently suitable for electric field control of magnetism, offering a route toward low power ICT applications. This study presents element specific evidence for a non-collinear magnetic structure in the single crystal M-type hexaferrite $$ based on vibrating sample magnetometry (VSM) and resonant soft X-ray diffraction (RSXD) measurements. Whilst the Co-Ti substitution is key to transforming the parent compound ($$) from a uniaxial collinear magnet to one with conical order at room temperature, the magnetic moments on the $$ ions, within the detection limit, do not contribute to the periodic non-collinear order, which is primarily driven by the Fe moments.