Instrumentation and Detectors
Activities of the Korea ALICE group for the development and production of the next-generation silicon tracker
Sanghoon Lim
ALICE 3 is the proposed next-generation heavy-ion experiment at the CERN Large
Hadron Collider (LHC), envisioned for operation during Run 5. The tracking system of ALICE 3 will consist of a high-precision vertex detector integrated into a retractable structure inside the beam pipe, complemented by a large-area outer tracker covering a broad pseudorapidity range. Both systems will be based on the Monolithic Active Pixel Sensor (MAPS) technology, building upon the developments realized for the recently upgraded ALICE Inner Tracking System (ITS2) and the future ITS3 upgrade. The total silicon area of the ALICE 3 tracking system is expected to be approximately five times larger than that of ITS2, presenting significant challenges in terms of large-scale sensor testing and module production. To address these challenges, research and development activities have been initiated in Korea, including the adaptation of an automated die-attach machine, commonly used in the
semiconductor packaging industry, for efficient sensor-to-substrate assembly. This contribution presents the ongoing efforts of the Korea ALICE group toward the development and production of the ALICE 3 silicon tracker. The scope includes sensor evaluation, automated assembly techniques, and prototype module construction, with the aim of establishing scalable procedures for future mass production.
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Instrumentation and Detectors
Energy calibration of bulk events in the BULLKID detector
M. Folcarelli, D. Delicato, A. Acevedo-Rentería et al. (+39 more)
BULLKID is a cryogenic, solid-state detector designed for direct searches of particle Dark Matter candidates, with mass $\lesssim 1$ GeV/c$^2$, and coherent
neutrino-
nucleus scattering. It is based on an array of dice carved in 5 mm thick silicon
crystal, sensed by
phonon-mediated Kinetic Inductance Detectors. In previous works, the array was calibrated with bursts of optical
photons, which are absorbed in the first hundreds nanometers of the dice and give rise to surface events. In this work, we present the reconstruction of bulk events through the 59.5 keV $\gamma$-ray generated by an $^{241}$Am source, which emulates more closely the interaction of Dark Matter and
neutrinos. The peak resolution is $5\%~(\sigma)$ and its position is shifted by less than $10\%$ with respect to the optical calibration. We observe that the resolution is further improved by a factor $2$ combining the signal from neighboring dice. These results confirm the performance of the detector in view of the physics goals of the BULLKID-DM experiment for dark matter search.
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All authors M. Folcarelli, D. Delicato, A. Acevedo-Rentería, L. E. Ardila-Perez, L. Bandiera, M. Calvo, M. Cappelli, R. Caravita, F. Carillo, U. Chowdhury, D. Crovo, A. Cruciani, A. D'Addabbo, M. De Lucia, G. Del Castello, M. del Gallo Roccagiovine, F. Ferraro, S. Fu, R. Gartmann, M. Grassi, V. Guidi, D. Helis, T. Lari, L. Malagutti, A. Mazzolari, A. Monfardini, T. Muscheid, D. Nicolò, F. Paolucci, D. Pasciuto, L. Pesce, C. Puglia, D. Quaranta, C. M. A. Roda, S. Roddaro, M. Romagnoni, G. Signorelli, F. Simon, A. Tartari, E. Vázquez-Jáuregui, M. Vignati, K. Zao
Physics and Society
Exploring the impact of multi-agent wealth exchange model on inequality reduction
Suchismita Banerjee
Binary kinetic exchange models, where money is shuffled between two
agents at a time, reproduce the Boltzmann Gibbs exponential wealth distribution but cannot address the multi party trades common in real
markets. We generalize the exchange rule to simultaneous interactions among more than two
agents in a closed economical system. We observe, as number of
agents grow, the stationary wealth distribution evolves smoothly from an exponential to an almost uniform distribution. Inequality metrics (Gini and k index) has been found to fall monotonically with the increase in
agents number. Compared with binary models that rely on saving propensities, which is also known to reduce inequality, we find the multi
agent interaction show a completely different behavior of inequality reduction.
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Computational Physics · Cross-listed from cond-mat.mes-hall
Geometry-Driven Charge and Spin Transport in $\beta12$ Borophene Quantum Dots
Seyed Mahdi Mastoor and Amirhossein Ahmadkhan Kordbacheh
Theoretical research has been conducted to study how geometry affects charge and
spin transport in $\beta\mathrm{12}$ borophene
quantum dots, which are confined systems. The study examined two distinct central regions, which included a circular disc and a regular hexagonal area that connected to semi-infinite zigzag and armchair borophene nanoribbon leads. The system was described by a five-band tight-binding
Hamiltonian parameterized using first-principles data, and the transport properties were calculated within the non-
equilibrium Green's function framework.
Spin resolved transmissions and
spin polarization were computed for a range of lead widths and proximity-induced exchange field strengths. The analysis revealed distinct transport characteristics determined by geometry and edge configuration: armchair-connected structures exhibited broader and more stable fully
spin-polarized windows compared with zigzag-connected counterparts. Furthermore, critical lead-width thresholds ($\approx 1.01$ nm for zigzag and $\approx 0.87$ nm for armchair) and a moderate exchange field above which complete
spin filtering occurs were identified. The results highlight the strong influence of edge termination and confinement geometry on transport properties and provide useful design guidelines for developing borophene-based nanoscale spintronic devices.
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Chemical Physics
Kinetic and Thermodynamic Descriptions of Open Systems of Complex Chemical Reactions with Multiple Scales
Liu Hong and Hong Qian
The general theory of a complex system of nonlinear chemical reactions is a primary
language of chemistry that includes chemical engineering and cellular biochemistry. Its significance as an analytical framework, however, has not been fully appreciated outside the community of physical chemists. In this review, we discuss the latest advances in the kinetics and Gibbsian thermodynamics of chemical reactions in a spatially homogeneous aqueous solution with a multiscale perspective on complex systems. From the microscopic level of single reaction events which are purely
stochastic in continuous time, one at a time among a set of molecules, to the macroscopic chemical reaction systems in bulk in terms of deterministic rate equations, the mathematical descriptions of kinetic models for chemical reactions at different levels are presented in detail, with rigorous mathematical justifications presented. In parallel with the kinetics of chemical reactions, the irreversible thermodynamics of open systems and the
stochastic thermodynamics along reactions trajectories are reviewed thoroughly. As a novel feature, the mathematical theory of large deviations is shown to play a pivotal role in the thermodynamics of chemical reactions in
equilibrium and in irreversible processes. This review is expected to stimulate interests in and help defining multiscale phenomena and nonequilibrium thermodynamics in many research fields on population dynamics of interacting species using chemical reactions as an analytic paradigm.
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Atomic Physics · Cross-listed from astro-ph.HE
Electron impact excitation of Te IV and V and Level Resolved R-matrix Photoionization of Te I - IV with application to modelling of AT2017gfo
Leo P. Mulholland, Catherine A. Ramsbottom, Connor P. Ballance et al. (+2 more)
Spectral modelling of kilonovae (KNe) require large amounts of collisional excitation and photoionization atomic data for lowly ionised (neutral, singly and doubly ionised) species of heavy elements. Much of the data currently used is calculated using approximate hydrogenic results or adopts semi-empirical formulae. We present atomic data for ions of tellurium (Te) computed using the well-known $R$-
matrix method. Results will also be presented for radiative and thermal collisions of Te IV and V, for which the required atomic data are also typically limited in the literature. The Multi-Configuration-Dirac-Hartree-Fock (MCDHF) method is used to produce model atomic structures and radiative rates. These model structures are then used to calculate electron-impact-excitation and photoionization cross-sections. The resulting excitation and radiative rates are further used in a collisional radiative model to produce synthetic spectra, which are compared with observations. We also investigate the possibility of Te IV contributing to the 1.08 $\mu$m emission feature in the mid-epochs of AT2017gfo alongside the established P-Cygni feature of Sr II.
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All authors Leo P. Mulholland, Catherine A. Ramsbottom, Connor P. Ballance, Albert Sneppen, Stuart A. Sim
Geophysics
Thermal Acoustical and Mechanical Characterization of Rock under in-situ conditions
Nima Haghighat, Hem B. Motra, Amir S. Sattari et al. (+1 more)
Data on the coupled influence of pressure and temperature on rock thermal conductivity remain limited. This study adapts a multi-anvil cubic press to enable steady-state thermal conductivity measurements under controlled in-situ conditions. The setup concurrently records P- and S-wave velocities along three orthogonal directions, providing unique real-time constraints on micro-structural
evolution. Beyond the expected temperature dependence, preliminary tests on two sandstones reveal a twofold pressure effect: increasing confining pressure enhances thermal conductivity through microcrack closure and better grain contacts, while simultaneously reducing the rate at which conductivity decreases with temperature. Initial results align closely with published
datasets, supporting the reliability of the developed methodology. Quantitatively, the thermal conductivity of the studied sandstones was found to decrease by an average of approximately 5.9% per 50 {\deg}C at the lowest confinement (12 MPa), compared with about 4.2% per 50 {\deg}C at the highest confinement (100 MPa). In addition, an average increase of roughly 1.4% per 10 MPa of applied confining pressure was observed for both samples.
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All authors Nima Haghighat, Hem B. Motra, Amir S. Sattari, Frank Wuttke
Medical Physics · Cross-listed from math.NA
A Review of Equation-Based and Data-Driven Reduced Order Models featuring a Hybrid cardiovascular application
Pierfrancesco Siena, Pasquale Claudio Africa, Michele Girfoglio et al. (+1 more)
Cardiovascular diseases are a leading cause of death in the world, driving the development of patient-specific and
benchmark models for blood flow analysis. This chapter provides a theoretical overview of the main categories of Reduced Order Models (ROMs), focusing on both projection-based and data-driven approaches within a classical setup. We then present a hybrid ROM tailored for simulating blood flow in a patient-specific aortic geometry. The proposed methodology integrates projection-based techniques with neural network-enhanced data-driven components, incorporating a lifting function strategy to enforce physiologically realistic
outflow pressure conditions. This hybrid methodology enables a substantial reduction in computational cost while mantaining high fidelity in reconstructing both velocity and pressure fields. We compare the full- and reduced-order solutions in details and critically assess the advantages and limitations of ROMs in patient-specific cardiovascular modeling.
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All authors Pierfrancesco Siena, Pasquale Claudio Africa, Michele Girfoglio, Gianluigi Rozza
Optics
Shifted rectangular mesh architecture for programmable photonics
Jacek Gosciniak
Programmable integrated photonics has evolved into a potent platform for implementing diverse optical functions on a single chip through software-driven reconfiguration. At the core of these processors are the photonic waveguide meshes that enable flexible light routing and manipulation. However, recirculating hexagonal waveguide meshes, which currently constitute the basic component of the mesh, are essentially limited by the fixed dimensions of their elementary
cells, which consist of as many as six components, limiting their spectral and temporal resolution. These limitations have a detrimental effect on the processing of broadband signals and the application of high-precision delay lines. Here, we introduce the concept of shifted rectangular waveguide mesh architecture for programmable photonics by shifting the adjacent columns or rows by a certain specific value. The operation of these shifted rectangular
cells is predicated on the rectangular shape of the
cell, which is associated with a smaller number of tunable basic units (TBUs), i.e., four, compared to
cells based on a hexagonal mesh, i.e., six. However, at the same time, they allow the signal to be redirected to the input port, which distinguishes them from the regular square mesh-based structure. This approach unlocks new degrees of freedom in programmable photonic
circuits, offering enhanced spectral and temporal tunability. Additionally, it paves the way for advanced application in topological photonics,
quantum information processing, neuromorphic and high-speed optical computing. The photonic chip arranged in this architecture is capable of implementing one or multiple simultaneous photonics
circuits with optical feedback paths and/or linear multiport transformations by the appropriate programming of its resources and the selection of its input and output ports.
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Classical Physics
Hyperelastic constitutive model for rubber-like materials based on the first Seth strain measures invariant
H. Bechir, Luc Chevalier, Mohend Chaouche et al. (+1 more)
The mechanical behaviour of isotropic and incompressible vulcanized natural rubbers (NR's) and that of quasi-incompressible carbon black filled vulcanized natural rubbers (NR 70) are considered both theoretically and experimentally. Based on the Seth strain measures in terms of the first invariant, an original form of the strain energy density function W is derived. This function is actually a generalisation of that of the neo-Hookean model and satisfies the hypothesis of the Valanis-Landel function. In the present study the analytical form of W is identified by using only simple tension test data (simple tension and simple planar compression). In our experiments, the two-dimensional field of in-plane homogeneous displacements is determined by using a home-developed image analysis cross-correlation technique. Our model is also identified using results taken from the literature in the case of (NR's) tested under simple tension, equibiaxial tension and pure shear. Comparison of numerical results with the experimental data indicates that the present model can characterise the hyperelastic behaviour of NR's and that of NR 70 for all the tested modes of deformation. Moreover, it seems to be valid over a wide range of deformation.
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All authors H. Bechir, Luc Chevalier, Mohend Chaouche, K. Boufala
Atomic Physics · Cross-listed from quant-ph
Trapped-ion two-qubit gates with >99.99% fidelity without ground-state cooling
A. C. Hughes, R. Srinivas, C. M. Löschnauer et al. (+6 more)
We introduce the 'smooth gate', an entangling method for trapped-ion
qubits where residual
spin-motion
entanglement errors are adiabatically eliminated by ramping the gate detuning. We demonstrate electronically controlled two-
qubit gates with an estimated error of $8.4(7)\times10^{-5}$ without ground-state cooling. We further show that the error remains $\lesssim 5\times10^{-4}$ for ions with average
phonon occupation up to $\bar{n}=9.4(3)$ on the gate mode. These results indicate that trapped-ion
quantum computation can achieve high fidelity at temperatures above the Doppler limit, which enables faster and simpler device operation.
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All authors A. C. Hughes, R. Srinivas, C. M. Löschnauer, H. M. Knaack, R. Matt, C. J. Ballance, M. Malinowski, T. P. Harty, R. T. Sutherland
Medical Physics
Optimized Single-Core PCF-Based SPR Biosensor for High-Performance Early-Stage Multi-Cancer Detection
Tonmoy Malakar, Miss Nourin Nurain Amina, Zarin Tasnim Nijhum et al. (+1 more)
In this study, we present a highly sensitive Surface Plasmon Resonance (SPR)-based biosensor integrated with a circular-
lattice Photonic
Crystal Fiber (PCF) for early-stage cancer detection. The proposed sensor leverages the synergy between SPR and PCF technologies to overcome the bulkiness and limited sensitivity of traditional SPR systems. A thin gold (Au) layer, responsible for plasmon excitation, is deposited on the fiber structure, while a nanolayer of vanadium pentoxide (V2O5) is introduced to enhance adhesion between the gold and the silica background, improving structural stability and field confinement. The sensor is designed to detect refractive index (RI) variations in biological analytes, specifically targeting cancerous
cells from skin, blood, and adrenal gland tissues. The optical characteristics and performance of the sensor were thoroughly analyzed using the Finite Element Method (FEM) in COMSOL Multiphysics 6.1, allowing for precise simulation and optimization. The sensor demonstrates high sensitivity within the RI range of 1.360-1.395, corresponding to the RI values of the target cancer
cells. Remarkable wavelength sensitivities of 21,250 nm/RIU, 53,571 nm/RIU, and 103,571 nm/RIU were achieved for skin, blood, and adrenal gland cancers, respectively. In addition, a maximum figure of merit (FOM) of 306.424 RIU^-1 and a spectral resolution (SR) of 9.57x10^-7 RIU further affirm the sensor's exceptional detection capabilities. These findings indicate the proposed SPR-PCF sensor's strong potential for real-time, label-free biosensing applications, particularly in precise and early cancer diagnostics.
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All authors Tonmoy Malakar, Miss Nourin Nurain Amina, Zarin Tasnim Nijhum, Nazmus Shakib Lalin
Instrumentation and Detectors
Leakage current of high-fluence neutron-irradiated 8" silicon sensors for the CMS Endcap Calorimeter Upgrade
CMS HGCAL collaboration
The HL-LHC will challenge the detectors with a nearly 10-fold increase in integrated luminosity compared to the previous LHC runs combined, thus the CMS detector will be upgraded to face the higher levels of radiation and the larger amounts of collision data to be collected. The High-Granularity Calorimeter will replace the current endcap calorimeters of the CMS detector. It will facilitate the use of particle-flow calorimetry with its unprecedented transverse and longitudinal readout/trigger
segmentation, with more than 6M readout channels. The electromagnetic section as well as the high-radiation regions of the hadronic section of the HGCAL (fluences above $10^{14}~n_{eq.}/cm^{2}$) will be equipped with silicon pad sensors, covering a total area of 620 m$^2$. Fluences up to $10^{16}~n_{eq.}/cm^{2}$ and doses up to 1.5 MGy are expected. The sensors are processed on novel 8" p-type wafers with an active thickness of 300 $\mu{}m$, 200 $\mu{}m$ and 120 $\mu{}m$ and cut into hexagonal shapes for optimal use of the wafer area and tiling. Each sensor contains several hundred individually read out
cells of two sizes (around 0.6 cm$^2$ or 1.2 cm$^2$). To investigate the radiation-induced bulk damage, the sensors have been irradiated with
neutrons at RINSC to fluences between $6.5 \times 10^{14}~n_{eq.}/cm^{2}$ and $1.4 \times 10^{16}~n_{eq.}/cm^{2}$. Electrical characterization results are presented for full sensors, as well as for partial sensors cut from multi-geometry wafers with internal dicing lines on the HV potential within the active sensor area. Leakage current behaviour is investigated for various sensor types and fluence levels, including its temperature dependence. Finally, methods to limit the annealing time of the sensors during irradiation are investigated by analysing the impact of splitting high-fluence irradiations.
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Atmospheric and Oceanic Physics
A purely analytical and physical wind turbine wake model accounting for atmospheric stratification
Emeline Noël, Erwan Jézéquel and Pierre-Antoine Joulin
A purely analytical wake model for wind turbines is derived, anchored exclusively in physical interactions between atmospheric
turbulence and turbine dynamics, and thus inherently accounting for atmospheric stratification. Unlike empirical models relying on assumed wake deficit shapes or tunable coefficients, this model predicts the wake deficit solely from measurable properties of the inflow, namely,
turbulence intensity and the
turbulence integral time scale. Systematic validation against Large Eddy Simulations (LES) for both IEA 15MW and NREL 5MW turbines, simulated in Meso-NH under stable, neutral, and unstable conditions, demonstrates excellent agreement across atmospheric regimes. Importantly, the model requires these specific
turbulence statistics as input but shows only weak sensitivity to the integral time scale, ensuring robustness even with moderate uncertainties in inflow characterisation. Comparative analysis with the state-of-the-art Super-Gaussian analytical model highlights superior performance of the present approach, particularly for unstable and neutral stratification. These results show that the predictive accuracy gained by incorporating richer inflow physics justifies the need for more comprehensive atmospheric inputs, providing a clear pathway for physically grounded, calibration-free wake modeling in operational wind energy contexts.
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Optics
Reflection and refraction properties of laser-driven 2D quantum well: Analogy with Photonic Time Crystal
Igor V. Smetanin and Alexander V. Uskov
It has been demonstrated that a
quantum well with optically excited, homogeneous oscillations of a two-dimensional (2D) electron
plasma behaves as a photonic time
crystal when it scatters an obliquely incident, weak probe electromagnetic wave. The hydrodynamic approximation is used to describe self-consistently the interaction between the probe wave and the 2D
plasma. Such a
quantum well becomes a polychromatic source and to the first order in perturbation reflected and transmitted radiation reveals as non-shifted in frequency principal components along with up- and down-shifted in frequency satellites. The downshifted satellites are backward propagating when the frequency of the probe wave is less than that of the
plasma oscillations. We found the condition when the downshifted components are the surface waves. For the s-polarized probe wave, we found that the
laser-driven
quantum well can support propagation of TE surface wave, which would not normally be permitted to propagate freely. The amplitudes of the reflected and transmitted components are determined for the principal components and the up- and down-shifted satellites.
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Atomic and Molecular Clusters · Cross-listed from quant-ph
Double electron resonance with two ensembles of nitrogen-vacancy centers in diamond
A. Chernyavskiy, I.S. Cojocaru, S.M. Drofa et al. (+8 more)
Nitrogen-vacancy (NV) centers in diamond are widely used in the development of a number of sensors. The sensitivity of these devices is limited by both the number of centers used and their coherent properties. While the effects on the coherent properties of paramagnetic
impurities such as carbon 13-isotopes and p1 centers are rather well understood, the mutual interaction of NV centers, which becomes especially important in relatively dense NV ensembles, is less well understood. Here, we provide a systematic study of NV-NV interaction using a dynamical double electron-electron resonance sequence, making it possible to directly observe the interaction of NV centers. Two types of dynamical DEER sequences were considered, consisting of 3 and 4 pulses. The nature of the phase jump in the 3-pulse sequence was attributed to the effect of non-commuting rotations within the sequence. Both the phase of the state vector rotation and its amplitude decay were studied, thus presenting a complete picture of decoherence due to NV-NV interaction. It was shown that the rate of the state vector decay differed significantly from predictions for a
spin 1/2 system. However, the decay rate observed in the DEER sequence remained a reliable indicator of the concentration of bath
spins and could be used to measure NV center concentration, provided that the
magnetic transition of NV centers is saturated.
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All authors A. Chernyavskiy, I.S. Cojocaru, S.M. Drofa, P.G. Vilyuzhanina, A.M. Kozodaev, V.G. Vins, A.N. Smolyaninov, S.Ya. Kilin, S.V. Bolshedvorskii, V.V. Soshenko, A.V. Akimov
Atomic Physics
Evaluation of Quantum Offset in Velocity Imaging-Based Electron Spectrometry
Rui Zhang, Shuaiting Yan, Wenru Jie et al. (+3 more)
Velocity-map imaging of electrons is a pivotal technique in chemical physics. A recent study reported a
quantum offset as large as 0.2 cm-1 in velocity imaging-based electron spectrometry [Phys. Rev. Lett. 134, 043001 (2025)]. In this work, we assess the existence this offset through a combination of simulations and experiments. Our simulations reveal that the velocity imaging results reconstructed using the maximum
entropy velocity Legendre reconstruction (MEVELER) method exhibit no such offset. Furthermore, experimental measurements of the electron affinity of oxygen conducted at various imaging voltages show no discernible offset attributable to the electric field in the photodetachment region. Therefore, we conclude that there is no evidence for the claimed
quantum offset in properly analyzed velocity imaging-based electron spectrometry.
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All authors Rui Zhang, Shuaiting Yan, Wenru Jie, Jiayi Chen, Qihan Liu, Chuangang Ning
Atomic Physics · Cross-listed from quant-ph
Kinetically-induced bound states in a frustrated Rydberg tweezer array
Mu Qiao, Romain Martin, Lukas Homeier et al. (+8 more)
Understanding how particles bind into composite objects is a ubiquitous theme in physics, from the formation of molecules to
hadrons in
quantum chromodynamics and the pairing of charge carriers in
superconductors. The formation of bound states usually originates from attractive interactions between particles. However, the binding can also arise purely from the motion of dopants due to kinetic frustration, which is potentially related to unconventional pairing in moiré materials. Here, we report the first direct observation of kinetically-induced bound states between holes and
magnons using a Rydberg atom array
quantum simulator of the bosonic $t$-$J$ model in frustrated ladders and 2D
lattices. First, we demonstrate the formation of mobile one-hole-one-
magnon bound states. We then construct three-particle one-hole-two-
magnon bound states and reveal the underlying binding mechanism by observing kinetically-induced singlet correlations. Finally, we investigate how mobile dopants structure their
magnetic environment in a
spin-balanced 2D triangular
lattice, showing that a hole induces $120^\circ$
antiferromagnetic order, while a doublon dopant generates in-plane
ferromagnetic correlations. Our results demonstrates compelling evidence of kinetically-induced binding, opening a new avenue to understand novel pairing mechanisms in correlated
quantum materials like
superconductors in moiré superlattices.
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All authors Mu Qiao, Romain Martin, Lukas Homeier, Ivan Morera, Bastien Gély, Lukas Klein, Yuki Torii Chew, Daniel Barredo, Thierry Lahaye, Eugene Demler, Antoine Browaeys
Physics and Society
Defining the urban "local" with low dimensional manifolds of human mobility networks
Hezhishi Jiang, Liyan Xu, Tianshu Li et al. (+7 more)
Urban science has largely relied on universal models, rendering the heterogeneous and locally specific nature of cities effectively invisible. Here we introduce a topological framework that defines and detects localities in human mobility networks. We empirically demonstrate that these human mobility network localities are rigorous
geometric entities that map directly to geographic localities, revealing that human mobility networks lie on
manifolds of dimension <=5. This representation provides a compact theoretical foundation for spatial
embedding and enables efficient applications to facility location and propagation modeling. Our approach reconciles local heterogeneity with universal representation, offering a new pathway toward a more comprehensive urban science.
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All authors Hezhishi Jiang, Liyan Xu, Tianshu Li, Jintong Tang, Zekun Chen, Yuxuan Wang, Haoran Liu, Hongmou Zhang, Huanfa Chen, Yu Liu
Atomic Physics
Perturbation-assisted Observation of the Lowest Vibrational Level of the $\mathrm{b}^{3}\Pi_{0}$ State of Ultracold LiK Molecules
Anbang Yang, Xiaoyu Nie, Hao Lin Yu et al. (+6 more)
The narrow transition from the lowest rovibrational level of the $\mathrm{X}^{1}\Sigma^{+}$ electronic ground state to the lowest vibrational level of the $\mathrm{b}^{3}\Pi_{0}$ potential provides opportunities for achieving magic-wavelength trapping of ultracold bialkali molecules for enhancing their rotational coherence times. Guided by existing spectroscopic data of several perturbed and deeply-bound rovibrational states of the $\mathrm{A}^{1}\Sigma^{+}$ potential [Grochola et al., Chem. Phys. Lett., 2012, 535, 17-20], we conducted a targeted spectroscopic search and report the first observation of the lowest vibrational level of the $\mathrm{b}^{3}\Pi_{0}$ state in $^{6}\mathrm{Li}^{40}\mathrm{K}$. The transition frequency from $|\mathrm{X}^{1}\Sigma^{+},\,v=0,\,J=0>$ to $|\mathrm{b}^{3}\Pi_{0},\,v'=0,\,J'=1>$ is determined to be 314,230.5(5)GHz. Assisted by microwave spectroscopy, we resolved the rotational structure of $|\mathrm{b}^{3}\Pi_{0},\,v'=0>$ and extracted a rotational constant of $h\times8.576(44)$ GHz for the $\mathrm{b}^{3}\Pi_{0}$ state. From this, we deducted an energy separation between $|\mathrm{b}^{3}\Pi_{0},v'=0,J'=0>$ and $|\mathrm{X}^{1}\Sigma^{+},v=0,J=0>$ of $hc\times$10,481.03(2) $\mathrm{cm}^{-1}$. Our work provides timely and precise information on the deeply-bound region of the $\mathrm{b}^{3}\Pi_{0}$ triplet excited potential of LiK, and benefits future applications of ultracold LiK isotopologues in
quantum simulation and
quantum computation that demand long coherence times.
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All authors Anbang Yang, Xiaoyu Nie, Hao Lin Yu, Yiming Liu, Victor Avalos, Canming He, Jacek Klos, Svetlana Kotochigova, Kai Dieckmann
Chemical Physics
System-Bath Modeling in Vibrational Spectroscopy via Molecular Dynamics: A Machine Learning Framework for Hierarchical Equations of Motion (HEOM)
Kwanghee Park, Ju-Yeon Jo and Yoshitaka Tanimura
Molecular vibrations in solutions, especially OH stretching and bending in water, drive ultrafast energy relaxation and dephasing in chemical and biological systems. We present a machine learning approach for constructing system-bath models of intramolecular vibrations in solution, compatible with
quantum simulations via the hierarchical equations of motion (HEOM). Using classical molecular dynamics trajectories generated with a force field specifically developed for
quantum molecular dynamics, the model captures anharmonic mode coupling and non-Markovian dissipation through spectral distribution functions (SDFs). These features, in turn, enable
quantum mechanical treatment of ultrafast energy relaxation, vibrational dephasing, and thermal excitation within the HEOM framework.. The trained model yields physically interpretable parameters, validated against infrared spectra. Notably, combining Brownian oscillator and Drude SDFs – representing inter- and intramolecular vibrational modes – significantly improves learning performance and supports rigorous simulation of nonlinear vibrational spectroscopy.
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Applied Physics · Cross-listed from cond-mat.mtrl-sci
Achieving Empirical Potential Efficiency with DFT Accuracy: A Neuroevolution Potential for the $\alpha$-Fe–C–H System
Fan-Shun Meng, Shuhei Shinzato, Zhiqiang Zhao et al. (+4 more)
A neuroevolution potential (NEP) for the ternary $\alpha$-Fe–C–H system was developed based on a database generated from
spin-polarized density functional theory (DFT) calculations, achieving empirical potential efficiency with DFT accuracy. At the same power consumption, simulation speeds using NEP are comparable to, or even faster than, those with bond order potentials. The NEP achieves DFT-level accuracy across a wide range of scenarios commonly encountered in studies of $\alpha$-Fe- and $\alpha$-Fe–C under hydrogen environments. The NEP enables large-scale atomistic simulations with DFT-level accuracy at the cost of empirical potentials, offering a practical tool to study hydrogen embrittlement in steel.
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All authors Fan-Shun Meng, Shuhei Shinzato, Zhiqiang Zhao, Jun-Ping Du, Lei Gao, Zheyong Fan, Shigenobu Ogata
Fluid Dynamics
Fluid-structure interaction analysis with interface control principle
Chungil Lee, Yoshiaki Abe, Yu Kawano et al. (+1 more)
An interface control principle is proposed for unsteady fluid-structure in- teraction (FSI) analyses. This principle introduces a method of explicitly controlling the interface motion in the temporal direction to minimize the residual force on the interface, which is defined as the discrepancy between the fluid and structural forces. The interface model is constructed using a data-driven approach that involves sparse identification of nonlinear dy- namics with control to evaluate the residual force. The interface model is subsequently subjected to control theory in order to minimize the residual force. Following the convergence of the residual force, the interface state is controlled to be that of the original unsteady FSI system. The fluid and structural simulations can be conducted independently without communication, as the interface state information is predetermined as inputs for each system. The proposed method is applied to the
vortex-induced vibration (VIV) of a cylinder at a Reynolds number of 150 under several reduced velocity conditions corresponding to the lock-in regime with limit-cycle oscillations. The results demonstrate that the residual force is sufficiently minimized in time, and when the residual force is close to zero, the predicted fluid force and structural displacement of the VIV show good agreement with the reference FSI simulation.
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All authors Chungil Lee, Yoshiaki Abe, Yu Kawano, Tomoki Yamazaki
Space Physics · Cross-listed from astro-ph.SR
Helium-3 Enrichment in Gradual Solar Energetic Particle Events: Evidence for Jet-Supplied Seed Population
R. Bucik, S. T. Hart, M. A. Dayeh et al. (+3 more)
Enhancements in 3He abundance, a characteristic feature of impulsive
solar energetic particle (ISEP) events, are also frequently observed in gradual SEP (GSEP) events. Understanding the origin of this enrichment is crucial for identifying the mechanisms behind SEP generation. We investigate the origin of 3He enrichment in high-energy (25-50 MeV)
solar proton events observed by SOHO, selecting events that coincide with <1 MeV/nucleon 3He-rich periods detected by ACE during 1997-2021. The identified 3He enhancements include cases where material from independent impulsive (3He-rich) SEP events is mixed with GSEP
proton populations. Two high-energy
proton events exhibit elemental composition and
solar source characteristics consistent with ISEPs. Extreme-ultraviolet imaging from SDO and STEREO reveals narrow, jet-like eruptions in the parent active regions of about 60% of the remaining events. Notably, the highest 3He/4He ratios occur when coronal jets are present, consistent with fresh, jet-driven injection of suprathermal 3He that is subsequently re-accelerated during the event. Correspondingly, jet-associated events show fewer pre-event (residual) 3He counts, indicating that enrichment in these cases does not primarily come from remnant material. We find a positive correlation between 3He/4He and Fe/O, strongest in jet-associated events, consistent with a common jet-supplied seed population re-accelerated by the CME shock.
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All authors R. Bucik, S. T. Hart, M. A. Dayeh, M. I. Desai, G. M. Mason, M. E. Wiedenbeck
Space Physics · Cross-listed from astro-ph.SR
Origin of Unusual Composition of 3He-Rich Solar Energetic Particles
R. Bucik, G. M. Mason, S. M. Mulay et al. (+3 more)
We examine 3He-rich
solar energetic particles (SEPs) detected on 2023 October 24-25 by
Solar Orbiter at 0.47 au. The measurements revealed that heavy-ion enhancements increase irregularly with mass, peaking at S. C, and especially N, Si, and S, stand out in the enhancement pattern with large abundances. Except for 3He, heavy ion spectra can only be measured below 0.5 MeV/nucleon. At 0.386 MeV/nucleon, the event showed a huge 3He/4He ratio of 75.2+/-33.9, larger than previously observed.
Solar Dynamics Observatory extreme ultraviolet data showed a mini filament eruption at the
solar source of 3He-rich SEPs that triggered a straight tiny jet. Located at the boundary of a low-latitude coronal hole, the jet base is a bright, small-scale region with a supergranulation scale size. The emission measure provides relatively cold source temperatures of 1.5 to 1.7 MK between the filament eruption and nonthermal type III
radio burst onset. The analysis suggests that the emission measure distribution of temperature in the
solar source could be a factor that affects the preferential selection of heavy ions for heating or acceleration, thus shaping the observed enhancement pattern. Including previously reported similar events indicates that the eruption of the mini filament is a common feature of events with heavy-ion enhancement not ordered by mass. Surprisingly, sources with weak
magnetic fields showed extreme 3He enrichment in these events. Moreover, the energy attained by heavy ions seems to be influenced by the size and form of jets.
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All authors R. Bucik, G. M. Mason, S. M. Mulay, G. C. Ho, R. F. Wimmer-Schweingruber, J. Rodriguez-Pacheco
Applied Physics
Event Topology-based Visual Microphone for Amplitude and Frequency Reconstruction
Ryogo Niwa, Yoichi Ochiai and Tatsuki Fushimi
Accurate vibration measurement is vital for analyzing dynamic systems across science and engineering, yet noncontact methods often balance precision against practicality. Event cameras offer high-speed, low-light sensing, but existing approaches fail to recover vibration amplitude and frequency with sufficient accuracy. We present an event
topology-based visual microphone that reconstructs vibrations directly from raw event streams without external illumination. By integrating the Mapper
algorithm from topological data analysis with hierarchical density-based clustering, our framework captures the intrinsic structure of event data to recover both amplitude and frequency with high fidelity. Experiments demonstrate substantial improvements over prior methods and enable simultaneous recovery of multiple sound sources from a single event stream, advancing the frontier of passive, illumination-free vibration sensing.
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Instrumentation and Detectors
Measurement of radon concentration in the output water of the 100~t/h ultrapure water system at the Jiangmen Underground Neutrino Observatory
C.B.Z. Luo, Q. Tang, C. Guo et al. (+7 more)
The Jiangmen Underground
Neutrino Observatory (JUNO), a 20 kton multi-purpose low background
liquid scintillator detector, was proposed primarily to determine the
neutrino mass ordering. To mitigate radioactivity from surrounding rock and enable
cosmic muon tagging, its central detector is immersed in a Water Cherenkov Detector (WCD) containing 40~ktons of ultrapure water instrumented with 2400 20-inch micro-channel plate photomultiplier tubes. Stringent radiopurity requirements mandate a radon concentration below 10 ~mBq/m$^3$ in the WCD. To achieve this, we developed a two-stage (ground and underground) ultrapure water system with 100~t/h production capacity, integrating a five-stage degassing membrane for radon removal. A novel microbubble technique was implemented to optimize the degassing membranes' radon removal efficiency. The synergistic combination of the microbubble technology and the multistage degassing membranes achieved a radon removal efficiency exceeding 99.9%, reducing the system's output to 0.61 $\pm$ 0.50~mBq/m$^3$ in recirculation mode, surpassing design specifications and establishing world-leading performance standards. This paper details the ultrapure system architecture, quantifies the radon contributions of each device, and presents a comprehensive study on microbubble-augmented membrane degassing for low radon ultra-pure water production in a 100~t/h water system.
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All authors C.B.Z. Luo, Q. Tang, C. Guo, B. Wang, J.C. Liu, Y.P. Zhang, L.D. Lv, L.P. Xiang, C.G. Yang, B. Xiao
Optics
Broadband and wide-angle beam deflection enabled by dynamically reconfigurable meta-arrays
Koffi-Emmanuel Sadzi and Abdoulaye Ndao
We present a structurally simple yet functionally ver- satile reflective meta-array composed of phase-change Antimony trisulfide (Sb2S3) nanorods enabling broad- band and wide-angle beam deflection in near-infrared. The device achieves over 80% deflection efficiency over a 1000 nm wide passband, and covering from O-band (1260 nm-1360 nm) to U-band (1565 nm-1625 nm) in the amorphous state. Meanwhile, in its crystalline state, we see a reduction of the efficiency to 40% on average with a maximum passband of 800 nm over the C-band. Moreover, its simple architecture simultaneously en- ables spectral filtering and beam splitting, delivering a compact, multifunctional solution optimized for high power applications.
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Optics
Beyond 350 GHz: Single-channel 112 Gbps photonic wireless transmission at 560 GHz using soliton microcombs
Yu Tokizane, Hiroki Kishikawa, Takumi Kikuhara et al. (+11 more)
Sixth-generation (6G) back-haul links will require terahertz (THz) carriers above 350 GHz to escape the congested 300 GHz band and support >100 Gbps data rates. Photonic THz transmitters have so far remained below 350 GHz because high-frequency photomixing suffers from phase noise and power limits. Here we demonstrate single-channel wireless transmission at 560 GHz using a fibre-packaged silicon-nitride
soliton microcomb as a compact, low-phase-noise optical reference. A high numerical aperture, UV-bonded fibre interface sustains
soliton operation for more than 24 hours with 1 W pump power. We phase-lock two distributed-feedback
lasers (DFBs) to adjacent comb lines and photomix them in a high-power uni-travelling-carrier photodiode, generating a 560 GHz carrier that bears in-phase and quadrature modulation. We achieve hard-decision forward-error-correction-qualified quadrature phase-shift keying and 16-quadrature amplitude modulation (16QAM) transmissions at 42 and 28 GBaud, respectively, attaining a record 112 Gbps data rate at 560 GHz. Relative to free-running DFBs, microcomb-locked photomixing cuts carrier linewidth and improves 16QAM error-vector magnitude. The results establish
soliton microcombs as compact and scalable frequency references for >100 Gbps sub-THz links and chart a path toward compact 6 G back-haul
radios.
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All authors Yu Tokizane, Hiroki Kishikawa, Takumi Kikuhara, Miezel Talara, Yoshihiro Makimoto, Kodai Yamaji Yasuhiro Okamura, Kenji Nishimoto, Eiji Hase, Isao Morohashi, Atsushi Kanno, Shintaro Hisatake, Naoya Kuse, Tadao Nagatsuma, Takeshi Yasui