Applied Physics
Strong actuation and optomechanical application of mass loaded membranes
Joe Depellette, Ewa Rej, Richa Cutting et al. (+1 more)
An increasing number of studies are moving towards the combination of
quantum mechanics and
gravity, where studying
gravity from a very small source mass is a viable starting point. Preparing for such experiments, investigations of weak gravitational forces have employed mechanical resonators to detect time-dependent gravitational forces from actuated source masses. Here, we demonstrate a source mass approach which utilizes capacitive actuation of a 1 mg gold sphere embedded on a silicon nitride membrane, rather than piezoelectric or motorized actuation. The design simultaneously provides a method for microwave optomechanical implementation by coupling the membrane position to the electromagnetic mode of a 3D cavity. The cavity quality factor is not significantly compromised by electromagnetic leakage to the actuation electrode, allowing DC and kilohertz AC voltages to be introduced in the region where electric fields are strongly concentrated. We measure over 700 nm of driven oscillation amplitude and more than ten percent tunability in the mechanical resonance frequency of the loaded membrane, giving the potential to match the oscillations to the frequency range of a detector in future experiments. An optomechanical readout is demonstrated by measuring the cavity resonance at cryogenic temperatures, while room temperature measurements provide complimentary understanding of the mechanisms which influence the mechanical response, including repulsive contact due to collisions within the device.
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All authors Joe Depellette, Ewa Rej, Richa Cutting, Mika A. Sillanpää
Medical Physics
Deformation and Stress Evolution during Laser Powder Bed Fusion of Semi-Crystalline Polyamide-12
Zhongfeng Xu, Wei Zhu, Lionel Freire et al. (+3 more)
Laser powder bed fusion (L-PBF) of semi-crystalline
polymers such as polyamide-12 (PA12) has found increasing use in various industrial applications. However, achieving high dimensional accuracy remains a significant challenge. Despite the seemingly straightforward layer-by-layer manufacturing concept, the L-PBF process involves complex thermal histories and strongly coupled multiphysics, making the
evolution of stress and deformation mechanisms still not fully understood. To address this, a comprehensive three-dimensional thermo-mechanical modeling framework is developed to simulate the L-PBF process of PA12. The model for the first time incorporates transient heat transfer, phase transformation induced volumetric shrinkage, thermoviscoelasticity, and a modified non-isothermal crystallization kinetics. To alleviate the computational burden of part-scale simulations, a dual-mesh strategy is employed to efficiently couple thermal and mechanical fields without compromising numerical accuracy, which also enables the framework to handle L-PBF simulations of arbitrarily complex three-dimensional geometries. Particular
attention is paid to the role of mechanical and thermal boundary conditions. Specifically, the underlying powder bed is modeled as a fictitious viscous medium, providing support while permitting upward displacement. Additionally, a radiative heat loss boundary condition, which more closely approximates the actual physical process, is applied to the top powder surface. The incorporation of this radiation effect significantly enhances the crystallization rate and improves the agreement with experimentally measured warpage. The model is validated against experimental warpage data under various preheating temperatures. Furthermore, strain decoupling analysis for the first time reveals that displacement induced by phase transformation is approximately 10 times greater than that caused by thermal expansion, highlighting the dominant role of crystallizationinduced shrinkage in warpage formation. Numerical tests also indicate that warpage is highly sensitive to the preheating target temperature of the PA12 powder bed, while the temperature of the newly recoated powder within the tested range has a limited effect. This work provides a predictive modeling foundation for future optimization of
polymer L-PBF processes at part-scale, particularly in controlling deformation and improving dimensional accuracy.
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All authors Zhongfeng Xu, Wei Zhu, Lionel Freire, Noëlle Billon, Jean-Luc Bouvard, Yancheng Zhang
Optics
Photonic Spiking Graph Neural Network for Energy-Efficient Structured Data Processing
Wanting Yu, Shuiying Xiang, Xingxing Guo et al. (+6 more)
Photonic computing shows great potential for signal processing and artificial intelligence (AI) acceleration due to its ultra-high speed, low energy consumption, and inherent parallelism. Existing photonic computing research has mainly focused on convolutional neural networks (CNNs) and fully connected neural networks (FCNNs), which are well suited for tasks such as image classification and object detection but face limitations in handling graph-structured data. Graph neural networks (GNNs) are specifically designed to model complex relational structures. In this work, we propose a photonic spiking graph neural network (PSGNN) architecture that integrates the structural modeling capability of GNNs, the temporal dynamics of spiking
neurons, and the parallel computing advantages of photonic hardware. Through hardware-software co-optimization, a bias-term simulation method tailored for photonic chips is implemented using feature-dimension expansion, enabling effective network training. Experiments on the KarateClub and PubMed
datasets achieve training accuracies of 100 percent (92 +/- 2 percent) and test accuracies of 97 percent (90 +/- 1 percent). A silicon photonics 4 x 4 Mach-Zehnder interferometer (MZI) array is further constructed for hardware validation, achieving a test accuracy of 93 percent. The system demonstrates an inference latency of 97 ps, with an energy efficiency of 280 GOPS/W and a computational density of 52 GOPS/mm^2. These results highlight the potential of PSGNN for structured-data processing applications.
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All authors Wanting Yu, Shuiying Xiang, Xingxing Guo, Shangxuan Shi, Haowen Zhao, Xintao Zeng, Yahui Zhang, Hongbo Jiang, Yue Hao
Atomic Physics
Real-time phase control methods for cold-atom interferometry
Mohamed Guessoum, Nathan Marliere, Charbel Cherfan et al. (+2 more)
We present two methods to achieve real-time inertial phase compensation in atom interferometers. Both methods, based on jumps of the position of the retroreflection mirror or frequencies of Raman
lasers, demonstrate similar state-of-the-art performance on our cold atom gyroscope, comparable to that of the reference method based on optical phase jumps. These alternative approaches broaden the scope of applications for real-time inertial phase compensation methods in atomic interferometers, particularly for space applications.
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All authors Mohamed Guessoum, Nathan Marliere, Charbel Cherfan, Remi Geiger, Arnaud Landragin
Optics
Optical design and characterization of a multi-depth vision simulator
Parviz Zolfaghari, Ehsan Varasteh, Koray Kavakli et al. (+3 more)
We present a
vision simulator device (Katsim), a compact near-eye optical display designed for assessing postoperative corrected
vision, preoperative intraocular lens (IOL) assessment, and objective IOL characterization. The system forms a virtual image using an amplitude-modulated LCoS spatial light modulator (AM-SLM), RGB LED illumination, and a high-speed varifocal lens. In the proposed architecture, the LED illumination and varifocal lens diopter changes are triggered in synchrony with the SLM RGB subframes, rendering three depth planes perceptually simultaneously via high-frequency time-multiplexing. Operating at 60 frames per second (fps), the system achieves an effective 180 Hz depth-coded cycle, enabling sharp, multi-depth rendering within a dynamically adjustable depth range from 0.2 m to optical infinity. The system's eyebox is configurable from 1 to 5 mm, while maintaining a fixed spatial location and preserving angular magnification regardless of changes in focus or eyebox size. The designed system features a 9.15-degree field of view. An integrated infrared pupil-tracking module detects non-cataractous regions of the cataractous crystalline lens, and the projected imagery is mechanically steered through those clear zones in real time. The proposed
vision simulator supports both subjective simulation of post-
surgical vision for patient-specific counseling and objective optical evaluation of IOLs, including resolution and contrast fidelity (e.g., modulation transfer function, contrast transfer function, and defocus curves). By decoupling depth modulation from eyebox position and size, the system offers a modular, portable platform that supports enhanced preoperative planning, personalized IOL selection, objective IOL characterization, and use as a novel research
vision tool.
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All authors Parviz Zolfaghari, Ehsan Varasteh, Koray Kavakli, Arda Gulersoy, Afsun Sahin, Hakan Urey
Chemical Physics
Flexible Framework for Surface Hopping: From Hybrid Schemes for Machine Learning to Benchmarkable Nonadiabatic Dynamics
Jakub Martinka, Mikołaj Martyka, Biman Medhi et al. (+2 more)
Nonadiabatic molecular dynamics is a key technique for investigating a broad range of photochemical and photophysical processes. Among the established approaches, surface hopping schemes are widely used and can be easily integrated with various
quantum chemistry programs or machine learning models. We present a flexible framework in MLatom that includes a newly implemented Tully's fewest-switches surface hopping
algorithm and its time-dependent Baeck–An variant. The capabilities of this framework are demonstrated through three representative examples corresponding to typical stages of a surface hopping study. First, we focus on methods providing energy, energy gradients and nonadiabatic couplings. We show that the flexibility of user-defined custom models can save computational time and that it is useful for benchmarking machine learning models. Next, we compare
curvature-driven surface hopping schemes and show that Landau–Zener approach outperforms the time-dependent Baeck–An scheme. Finally, we showcase easy-to-use analysis tools for both individual trajectories and trajectory ensembles. This framework enables accelerated development of machine learning models and provides deeper insight into nonadiabatic dynamics. It is available as a part of the open-source MLatom package.
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All authors Jakub Martinka, Mikołaj Martyka, Biman Medhi, Jiří Pittner, Pavlo O. Dral
Instrumentation and Detectors · Cross-listed from hep-ex
Aerogel RICH Counter at the Belle II Detector
I. Adachi, N. Akopov, D. Augueste et al. (+36 more)
We report on the design, operation, and performance of a novel proximity-focusing Ring Imaging Cherenkov (RICH) detector equipped with a multilayer focusing aerogel radiator, developed for the forward region of the Belle II spectrometer at the SuperKEKB $e^+e^-$
collider. The system achieves effective separation of charged pions, kaons, and
protons across the full kinematic range of the experiment, from 0.5 GeV/c to 4 GeV/c. To date, the detector has successfully operated in data-taking, contributing to the collection and analysis of nearly 600/fb of Belle II $e^+e^-$ collision data.
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All authors I. Adachi, N. Akopov, D. Augueste, J. Bonis, L. Burmistrov, S. Dey, R. Dolenec, G. Ghevondyan, R. Giordano, A. Hvala, T. Iijima, S. Iwata, H. Kakuno, G. Karyan, H. Kawai, T. Kohriki, T. Konno, S. Korpar, P. Krizan, S. Kurokawa, Y. Lai, A. Lozar, M. Mrvar, G. Nazaryan, S. Nishida, S. Ogawa, R. Pestotnik, I. Prudiiev, L. Santelj, A. Seljak, L. Senekovic, M. Shoji, K. Spenko, T. Sumiyoshi, M. Tabata, K. Uno, E. Waheed, M. Yonenaga, Y. Yusa
Medical Physics
Classical and relativistic balance of configurational forces
Rodrigue Desmorat, Anthony Gravouil and Boris Kolev
This article develops a unified variational framework for configurational (or material) forces in both Classical (3D, non-relativistic) and Relativistic (4D) Continuum Mechanics. Configurational forces describe the
evolution of material defects-such as cracks, dislocations, and interfaces-which move relative to the material rather than through physical space. In the classical setting of hyperelasticity, the authors revisit the balance of configurational forces using an intrinsic Lagrangian formulation, where the material body is modeled as an abstract three-dimensional
manifold. By treating the reference configuration as a variable and performing a Lagrangian variation with respect to it, they show that the configurational forces balance naturally emerges. Importantly, this balance equation is not independent: it is equivalent to the standard balance of linear momentum combined with constitutive relations, and it is expressed through the Eshelby stress tensor on the reference configuration. The framework is then extended to Relativistic Hyperelasticity within General Relativity. Matter is described by a matter field, a vector valued function, defined on the four-dimensional Universe, and the Lagrangian (i.e., Action) includes both matter and gravitational contributions. Two stress-energy tensors arise: the Noether stress-energy tensor (from variations with respect to the matter field) and the
Hilbert stress-energy tensor (from variations with respect to the Universe metric). Assuming General Covariance, the authors prove that these tensors and their associated balance laws are equivalent. By introducing the notion of an observer and specializing to static spacetimes, the authors define a relativistic generalization of the deformation and derive a four-dimensional Eshelby tensor. They show that in Special Relativity, as in Classical Continuum Mechanics, the relativistic configurational forces balance is not a new equation but follows from the conservation laws of the Noether stress-energy tensor. Finally, they recover the classical configurational forces balance as the non-relativistic limit of the relativistic theory. Overall, the paper provides a rigorous
geometric and variational interpretation of configurational forces, unifying classical and relativistic formulations and clarifying their deep connection with standard
equilibrium equations.
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Instrumentation and Detectors
Design, simulation and performance of the resistive-anode PICOSEC Micromegas detector
Djunes Janssens, Antonija Utrobicic, Marinko Kovacic et al. (+52 more)
The PICOSEC Micromegas detector is a Micro-Pattern Gaseous Detector concept developed to achieve tens of picosecond timing resolution for charged particle detection by combining a Cherenkov radiator with a two-stage Micromegas amplification structure. To improve operational robustness, a resistive anode has been implemented using a DLC layer deposited on a Kapton substrate. While this design enhances detector stability, the resistive layer may influence rate capability, signal formation, and detector capacitance, altering timing performance. This work presents a comprehensive study of a resistive design, including an analytical model and finite-element simulations to quantify rate-dependent gain reduction due to ohmic voltage drop on the resistive layer. An analytical solution for the voltage across a finite-size resistive layer is derived, and a numerical model is developed to evaluate gain suppression under intense particle fluxes. The impact of the resistive layer on signal formation is investigated using time-dependent weighting fields and the Garfield++ simulation framework. The contribution of signal components induced by the resistive layer is quantified, and preservation of the signal leading edge is found for surface resistivities above 100 kohm per square. Single-channel resistive-anode prototypes were designed, constructed, and experimentally characterized. Laboratory measurements using single photoelectrons and power spectral density analysis show the predicted reduction in signal amplitude while preserving the leading edge.
Muon beam tests with CsI and DLC photocathodes demonstrate a time resolution of 11.5 ps for CsI, comparable to 11.9 ps for the metallic-anode device, showing the suitability of the resistive design for precision timing applications.
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All authors Djunes Janssens, Antonija Utrobicic, Marinko Kovacic, Marta Lisowska, Eraldo Oliveri, Florian Brunbauer, Karl Floethner, Hans Muller, Rui De Oliveira, Giorgio Orlandini, Leszek Ropelewski, Lucian Scharenberg, Thomas Schneider, Miranda van Stenis, Rob Veenhof, Thomas Papaevangelou, Roy Aleksan, Stephane Aune, Thomas Gustavsson, Alexandra Kallitsopoulou, Philippe Legou, Michal Pomorski, Emmanuel Scorsone, Lukas Sohl, Mariam Kebbiri, Spyros Tzamarias, Dimos Sampsonidis, Yannis Angelis, Ioannis Maniatis, Ioannis Karakoulias, Jonathan Bortfeldt, Ilaria Vai, Matteo Brunoldi, Davide Fiorina, Paolo Vitulo, Jaydeep Datta, Nathan Shankman, Kondo Gnanvo, Klaus Dehmelt, Brian Kross, Jack McKisson, Akash Pandey, George Fanourakis, Michele Gallinaro, Francisco Garcia, Yi Zhou, Jianbei Liu, Yue Meng, Xu Wang, Zhiyong Zhang, Michael Lupberger, Yorgos Tsipolitis, Maja Mičetić, Krešimir Salamon, Sebastian White
Applied Physics · Cross-listed from quant-ph
Reactive near-field subwavelength microwave imaging with a non-invasive Rydberg probe
Chaoyang Hu, Mingyong Jing, Zongkai Liu et al. (+10 more)
Non-invasive microwave field imaging–accurately mapping field distributions without perturbing them–is essential in areas such as aerospace engineering, biomedical imaging and integrated-
circuit diagnostics. Conventional metal probes, however, inevitably perturb reactive near fields: they act as strong scatterers that drive induced currents and secondary radiation, remap evanescent components and thereby degrade both accuracy and spatial resolution, particularly in the reactive near-field regime that is most relevant to these applications. Here we demonstrate, to our knowledge for the first time, reactive near-field subwavelength imaging of microwave fields using the
quantum non-demolition properties of Rydberg atoms, realized with a compact, non-invasive single-ended fibre-integrated Rydberg probe engineered to minimize field disturbance. The probe achieves an imaging resolution of {\unboldmath$\lambda/56$}, and the measured field distributions agree with full-wave simulations with structural similarity approaching unity, confirming both its subwavelength spatial resolution and its genuinely non-invasive character compared with conventional metal-based probes. Because the atomic sensor is intrinsically isotropic, the same device can faithfully image multi-dimensional field structures without orientation-dependent calibration. Our results therefore establish a general, non-invasive route to high-accuracy, subwavelength reactive near-field microwave imaging, with particular promise for applications such as chip-defect detection and integrated-
circuit diagnostics, where even small perturbations by the probe can mask the underlying physics of interest.
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All authors Chaoyang Hu, Mingyong Jing, Zongkai Liu, Shaoxin Yuan, Bin Wu, Yan Peng, Tingting Li, Wenguang Yang, Junyao Xie, Hao Zhang, Liantuan Xiao, Suotang Jia, Linjie Zhang
Optics
Segmentation-Engineered Ge4Sb6Te7 Switch on SOI Platform for Multilevel Non-Volatile Photonic Neural Inference
Arpan Sur, Sudipta Saha, Chih-Yu Lee et al. (+1 more)
Phase-change materials (PCMs) have emerged as key enablers of non-volatile, ultra-compact photonic switches for energy-efficient deep neural network (DNN) applications. In this work, we investigate the recently discovered $\mathrm{Ge_{4}Sb_{6}Te_{7}}$ (GST-467) as a high-contrast optical PCM and demonstrate its suitability for multi-level photonic computing. The complex refractive indices of amorphous and crystalline GST-467 were experimentally extracted and used to propose a segmented silicon-on-
insulator photonic switch optimized at 1550 nm. Three-dimensional FDTD simulations reveal that
segmentation significantly enhances the extinction ratio while maintaining low insertion loss, resulting in a more than seven times higher design figure of merit than an unsegmented design.
Laser-induced thermo-optical simulations further establish efficient, reversible switching with sub-nJ energy requirements for crystallization and amorphization. Compared with established GST, GSST, and GSS compositions, GST-467 provides the largest transmission contrast and supports up to 48 resolvable optical states. When deployed as multi-level weights in photonic DNN architectures, the GST-467 switch achieves superior classification accuracy on EMNIST and Fashion-MNIST
benchmarks. These results position GST-467 as a highly promising PCM for scalable, low-energy photonic computing and neuromorphic hardware.
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All authors Arpan Sur, Sudipta Saha, Chih-Yu Lee, Ichiro Takeuchi
Computational Physics
Renormalization-Group Geometry of Homeostatically Regulated Reentry Networks
Byung Gyu Chae
Reentrant computation-recursive self-coupling in which a network continuously reinjects and reinterprets its own internal state-plays a central role in biological cognition but remains poorly characterized in neural network architectures. We introduce a minimal continuous-time formulation of a homeostatically regulated reentrant network (FHRN) and show that its population dynamics admit an exact reduction to a one-dimensional radial flow. This reduction reveals a dynamically fixed threshold for sustained reflective activity and enables a complete renormalization-group (RG) analysis of the reentry-homeostasis interaction. We derive a closed RG system for the parameters governing structural gain, homeostatic stiffness, and reentrant amplification, and show that all trajectories are attracted to a critical surface defined by $\gamma\rho=1$, where intrinsic leak and reentrant drive exactly balance. The resulting phase structure comprises quenched, reactive, and reflective regimes and exhibits a mean-field critical onset with universal scaling. Our results provide an RG-theoretic characterization of reflective computation and demonstrate how homeostatic fields stabilize deep reentrant transformations through scale-dependent self-regulation.
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Applied Physics
Antichiral surface states and higher-order topological states based on a modified Haldane model
Jia-Rui Xu, Zhan Xiong, Kai Deng et al. (+4 more)
Antichiral surface states, characterized by unidirectional propagation on parallel surfaces, offer unique potential for controlling classical waves. However, their realization typically relies on complex implementations of the two-dimensional modified Haldane model, limiting practical applications. Here, we propose a simplified scheme to realize such states within the nodal-line semimetal phase of a single-layer honeycomb
lattice, by emulating the essential physics of the modified Haldane model through an introduced layer degree of freedom. Furthermore, we demonstrate that unequal vertical interlayer couplings can generate valley higher-order topological partial bandgaps, hosting coexisting one-dimensional hinge states and gapped antichiral surface states. We numerically verify these multiple topological states in acoustic
crystals, establishing a versatile platform for advanced wave manipulation.
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All authors Jia-Rui Xu, Zhan Xiong, Kai Deng, Hai-Xiao Wang, Shiyang Liu, Yixian Qian, Jian-Hua Jiang
Optics
A fast, large-scale optimal transport algorithm for holographic beam shaping
Andrii Torchylo, Hunter Swan, Lucas Tellez et al. (+1 more)
Optimal transport methods have recently established state of the art accuracy and efficiency for
holographic laser beam shaping. However, use of such methods is hindered by severe $\mathcal{O}(N^2)$
memory and $\mathcal{O}(N^2)$ time requirements for large scale input or output images with $N$ total pixels. Here we leverage the dual formulation of the optimal transport problem and the separable structure of the cost to implement
algorithms with greatly reduced $\mathcal{O}(N)$
memory and $\mathcal{O}(N\log N)$ to $\mathcal{O}(N^{3/2})$ time complexity. These
algorithms are parallelizable and can solve megapixel-scale beam shaping problems in tens of seconds on a CPU or seconds on a GPU.
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All authors Andrii Torchylo, Hunter Swan, Lucas Tellez, Jason M. Hogan
Chemical Physics
Non-Dichroic Enantio-Sensitive Chiroptical Spectroscopy
Letizia Fede, Debobrata Rajak, Chris Sparling et al. (+8 more)
Chiroptical effects using circularly polarized light produce signals that change sign when switching either molecular handedness (enantiosensitivity) or the light helicity (circular dichroism). Here, we break this enantiosensitive-and-dichroic paradigm by measuring a new type of chiroptical signal which is enantiosensitive but not dichroic. We photoionize
chiral molecules using a strong
laser field and detect the three-dimensional photoelectron momentum distribution. The non-dichroic, enantiosensitive asymmetry is encoded in octupolar and higher multipolar terms in the photoelectron angular distribution, which appear in multiphoton ionization with elliptically polarized fields or cross polarized two-color fields. The robustness of the enantiosensitivity with respect to the relative phase between the vectorial components of the ionizing field represents an example of
symmetry protection, and opens unexplored opportunities for imaging ultrafast dynamics in
chiral molecules, such as enantiosensitive photoelectron spectroscopy with bright squeezed
vacuum states.
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All authors Letizia Fede, Debobrata Rajak, Chris Sparling, David Ayuso, Valérie Blanchet, Piero Decleva, Dominique Descamps, Stéphane Petit, Bernard Pons, Yann Mairesse, Andrés Ordóñez
Medical Physics
Enhanced Vascularity in Gelatin Scaffolds via Copper-Doped Magnesium-Calcium Silicates Incorporation: In-Vitro and Ex-Ovo Insights
Erfan Salahinejad, Avaneesh Muralidharan, Forough Azam Sayahpour et al. (+4 more)
Addressing a critical challenge in current tissue-engineering practices, this study aims to enhance vascularization in 3D porous scaffolds by incorporating bioceramics laden with pro-angiogenic ions. Specifically, freeze-dried gelatin-based scaffolds were infused with sol-gel-derived powders of Cu-doped akermanite (Ca2MgSi2O7) and bredigite (Ca7MgSi4O16) at various concentrations (10, 20, and 30 wt%). The scaffolds were initially characterized for their structural integrity, biodegradability, swelling behavior, impact on physiological pH, and cytocompatibility with human umbilical vein endothelial
cells (HUVECs). The silicate incorporation effectiveness in promoting vascularity was then assessed through HUVEC attachment, capillary tube formation, and ex-ovo chick embryo chorioallantoic membrane assays. The findings revealed significant improvements in both in-vitro and ex-ovo vascularity of the gelatin scaffolds upon the addition of Cu-doped akermanite. The most effective concentrations were determined to be 10 and 20%, which led to notable HUVEC metabolic activity, a well-spread morphology with extensive peripheral filopodia and lamellipodia at 10% and a cobblestone phenotype indicative of in-vivo endothelium at 20% during
cell attachment, the formation of complex networks of tubular structures, and robust vascularization in chick embryo development. Moving forward, the incorporation of Cu-doped akermanite into tissue-engineering scaffolds shows great potential for addressing the limitations of vascularization, especially for critical-sized bone defects, by facilitating the controlled release of pro-angiogenic and pro-osteogenic ions.
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All authors Erfan Salahinejad, Avaneesh Muralidharan, Forough Azam Sayahpour, Maryam Kianpour, Mohsen Akbarian, Daryoosh Vashaee, Lobat Tayebi
Atomic Physics · Cross-listed from gr-qc
Quantum sensing of high-frequency gravitational waves with ion crystals
Asuka Ito, Ryuichiro Kitano, Wakutaka Nakano et al. (+1 more)
A detection method for high-frequency gravitational waves using two-dimensional ion
crystals is investigated. Gravitational waves can resonantly excite the drumhead modes of the ion
crystal, particularly the parity-odd modes. In the optical dipole force protocol,
entanglement between the drumhead modes and the collective
spins transfers the excitation of the drumhead modes to the rotation of the total
spin. Furthermore, gravitational wave detection beyond the standard
quantum limit becomes possible as a squeezed
spin state is generated through this
entanglement. The sensitivity gets better with a larger ions
crystals as well as a larger number of the ions. Future realization of large ion
crystals can significantly improve the sensitivity to gravitational waves in the 10 kHz to 10 MHz region.
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All authors Asuka Ito, Ryuichiro Kitano, Wakutaka Nakano, Ryoto Takai
Optics · Cross-listed from quant-ph
Critical reexamination of a recent challenge to Bohmian mechanics
S. Di Matteo and C. Mazzoli
We reanalyze a recent experiment by Sharoglazova et al. [Nature (London) 643, 67 (2025)] highlighting the role of the transient regime. We prove that in the evanescent state of the stationary regime their experimental data can be interpreted in terms of Bohmian
quantum mechanics. At the same time, Bohm's
quantum potential can be reinterpreted as a kinetic-energy term in the framework of Nelson's
stochastic quantum mechanics, with a hidden-variable, nonclassical speed fitting the experimental data as well. The experiment can be interpreted as well within orthodox
quantum mechanics and is therefore not conclusive in selecting or challenging any framework.
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Physics and Society
Various Vicsek Models with Underlying Network Characteristics
Haoshuai Wang, Zhaoqi Dong and Lei Chen
Collective motion is a fundamental phenomenon in biological swarms. As a framework for studying synchronization in motions, the Vicsek model is simple and efficient, assuming isotropic interactions with a complete field of view. Drawing inspiration from natural swarms, we incorporate realistic constraints into the model. By analysing the interaction structures from the complex network perspective, we demonstrate that models with the homogeneous interaction rules naturally form Erdos-Renyi networks, whereas the introduction of heterogeneity leads to Barabasi-Albert networks. Furthermore, we discover that the model's synchronization is fundamentally governed by the average degree of the interaction network. Through a comparative analysis across these
topologies, we identify a stretched-exponential relationship between the average degree and the synchronization metrics.
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Applied Physics · Cross-listed from cond-mat.mtrl-sci
Enhanced sinterability and in vitro bioactivity of diopside through fluoride doping
E. Salahinejad and M. Jafari Baghjeghaz
In this work, diopside (CaMgSi2O6) was doped with fluoride at a level of 1 mol.%, without the formation of any second phase, by a wet chemical precipitation method. The sintered structure of the synthesized nanopowders was studied by X-ray diffraction,
Fourier transform infrared spectroscopy and field-emission scanning electron microscopy. Also, the samples' in vitro apatite-forming ability in a simulated body fluid was comparatively evaluated by electron microscopy, inductively coupled
plasma spectroscopy and
Fourier transform infrared spectroscopy. According to the results, the material's sinterability was improved by fluoride doping, as realized from the further development of sintering necks. It was also found that compared to the undoped bioceramic, a higher amount of apatite was deposited on the surface of the doped sample. It is concluded that fluoride can be considered as a doping
agent in magnesium-containing silicates to improve biological, particularly bioactivity, behaviors.
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Optics
Near-field-driven Radiative Thermal Dynamics in Aperiodic Nanostructures
M. Prado, A. Manjavacas, F. A. Pinheiro et al. (+1 more)
Harnessing structural correlations in near-field plasmonic and polaritonic systems hold untapped potential for controlling light-matter interactions at the nanoscale. By tuning these correlations, one can reshape mode localization, coupling, and spectral distribution which are properties central to manipulating energy transport and field enhancement in nanophotonic platforms. We exploit Vogel spirals, an aperiodic geometry where a single parameter dictates spatial correlations, to show how correlation strength reshapes the modal spectrum and transient dynamics of near-field coupling. As a proof of concept, we demonstrate that aperiodic configurations outperform both uncorrelated (random) and periodic arrays in controlling near-field radiative heat-transfer dynamics. These results establish deterministic aperiodic order as a powerful platform for tailoring correlated electromagnetic responses in next-generation nanophotonic devices.
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All authors M. Prado, A. Manjavacas, F. A. Pinheiro, W. J. M. Kort-Kamp
Physics and Society
Evolutionary Cooperation with Game Transitions via Markov Decision Chain in Networked Population
Chaoyang Luo, Yuji Zhang, Minyu Feng et al. (+1 more)
Individual cooperative strategy influences the surrounding dynamic population, which in turn affects cooperative strategy. To better model this phenomenon, we develop a Markov decision chain based game transitions model and examine the dynamic transitions in game states of individuals within a network and their impact on the strategy's
evolution. Additionally, we extend single-round strategy imitation to multiple rounds to better capture players' potential non-rational behavior. Using intensive simulations, we explore the effects of transition probabilities and game parameters on game transitions and cooperation. Our study finds that strategy-driven game transitions promote cooperation, and increasing the transition rates of Markov decision chains can significantly accelerate this process. By designing different Markov decision chains, these results provide simulation based guidance for practical applications in swarm intelligence, such as strategic collaboration.
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All authors Chaoyang Luo, Yuji Zhang, Minyu Feng, Attila Szolnoki
Plasma Physics
Non-Inductive Current Start-Up Using Multi-Harmonic Electron Cyclotron Wave and Current Ramp-Up Through Combined Electron Cyclotron Wave and Ohmic Heating in EXL-50U Spherical Torus
Xinchen Jiang, Yuejiang Shi, Yueng-Kay Martin Peng et al. (+21 more)
The non-inductive current start-up by multi-harmonic electron cyclotron wave has been systematically investigated in the EXL-50U spherical
torus. Significant enhancements of the driven current with increasing number of resonance layers have been demonstrated by variation of the number of harmonic resonance layers of the ECW through adjustment of the
magnetic field or
plasma cross section. The critical role of multi-harmonic ECW in enhancing the driven current has been experimentally verified for the first time. To explain the related experimental observations, a physical mechanism involving multi-harmonic heating, multiple reflections, and multi-pass absorption - leading to the generation of high-energy electrons via X-mode wave or electron Bernstein wave has been proposed. The current drive capacity of the first harmonic extraordinary mode of the ECW has also been experimentally confirmed for the first time. After the application of Ohmic heating during the current ramp-up phase, the current drive efficiency of ECW is further enhanced. Leveraging the synergistic effect between ECW and Ohmic heating, EXL-50U achieved a
plasma current of 1 MA, with the non-inductively driven current fraction reaching 70%.
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All authors Xinchen Jiang, Yuejiang Shi, Yueng-Kay Martin Peng, Shaodong Song, Wenjun Liu, Xianming Song, Xiang Gu, Ji Qi, Dong Guo, Debabrata Banerjee, Lili Dong, Zhenxing Wang, Chunyan Li, Junquan Lin, Pingwei Zheng, Haojie MA, Huasheng Xie, Jiaqi Dong, Qingwei Yang, Yunfeng Liang, Baoshan Yuan, Xianmei Zhang, Minsheng Liu, EXL-50U team
Atomic and Molecular Clusters · Cross-listed from cond-mat.mes-hall
Migration of gold atoms into a thiol-bonded molecular self-assembled monolayer, forming a cluster exhibiting a Coulomb staircase
Bingxin Li, Shanglong Ning, Chunyang Miao et al. (+16 more)
Thiol-based self-assembled monolayers (SAMs) on gold surfaces are one of the fundamental building blocks of molecular electronics. The strong chemical affinity of the gold and sulfur (Au-S) enables the formation of close-packed SAMs, but it also has recently been found to create a dynamic interface where surface reconstruction can occur under illumination, even with ambient light. This reconstruction may facilitate migration of gold atoms, potentially leading to in-situ formation of gold clusters. However, research on this mechanism often centers on Au(111) crystalline surfaces and flicker-noise measurements. Electron transport in ensembles of molecules in lithographically defined junctions has remained largely unexplored at cryogenic temperatures. In this study, we observe single-electron phenomena characterized by reproducible Coulomb staircases across various long-chain alkanethiol SAMs, which fit the Coulomb-blockade theory of nm-sized metallic nanoparticles. We find no such current steps in samples with amine, rather than thiol, anchors. Additionally, we find that by adding a bipyridyl functional group, these phenomena can be harnessed for memristive switching and negative differential resistance. These findings indicate that the generally observed lack of reliability and reproducibility of molecular devices may be alleviated by using amine anchors instead of thiols to avoid nanoparticle effects. Conversely, the spontaneous formation of the nanoparticles could potentially be controlled and used to achieve useful functionalities, offering new pathways for designing multifunctional nanoelectronic components.
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All authors Bingxin Li, Shanglong Ning, Chunyang Miao, Chenyang Guo, Gyu Don Kong, Xintai Wang, Victor I. Coldea, Yuqiao Li, Sam Harley, Oleg V. Kolosov, James Newson, Sam P. Jarvis, Ben J. Robinson, Mohammed Alzanbaqi, Ali Ismael, Colin J. Lambert, Hyo Jae Yoon, Jeremy J. Baumberg, Christopher J. B. Ford
Optics
Visualizing and Optimizing Phase Matching in Nonlinear Guided-mode Resonators with the Green's Function Integral Method
Chengkang Liang, Quanying Li, Jiale Xu et al. (+2 more)
Efficient nonlinear frequency conversion in nanophotonics requires not only strong fundamental field but also precise phase matching among distributed nonlinear sources. Here, we develop the two-dimensional Green's function integral method (GFIM), which enables direct visualization and optimization of phase matching in nonlinear guided-mode resonators. Using GFIM phase analysis, we generalize the phase-matching factor (PMF) as a rigorous metric of spatial phase coherence in harmonic generation, revealing severe phase mismatch in conventional guide mode resonators. Guided by phase-matching profiles, we propose design strategies to improve the phase coherence, particularly by introducing a high-index waveguide layer that confines the fundamental field in the nonlinear material to regions where the harmonic Green's function varies slowly. This configuration achieves a PMF exceeding 0.91, approaching the ideal value of unity, and yields a record SHG efficiency of 26.7% at a low pump intensity of 2 kW/$\mathrm{cm}^2$. These results establish the GFIM-based phase-matching visualization as an effective strategy for compact, high-performance nonlinear photonic devices.
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All authors Chengkang Liang, Quanying Li, Jiale Xu, Pingqi Gao, Jiancan Yu