Optics · Cross-listed from quant-ph
Storage of telecom-band time-bin qubits in thin-film lithium niobate
Xiao-Jie Wang, Yong-Teng Wang, Zi-Wei Zhao et al. (+2 more)
Integrated photonics has emerged as a promising platform for
quantum communication and
quantum computation. Thin-film lithium niobate (TFLN) has gained significant
attention in this field due to its exceptional optical properties, enabling the realization of numerous integrated photonic devices. However,
quantum memory, which serves as a universal building block for the
quantum internet, has not yet been demonstrated in TFLN. In this study, we realized the first on-chip
quantum memory using erbium ions doped TFLN. The developed
quantum memory achieves a storage time of 400 ns with an efficiency of 1.95%, significantly outperforming conventional waveguide delay lines. The multimode capability is demonstrated by successfully storing four temporal modes. Furthermore, single-
photon-level coherent pulses are encoded into time-bin
qubits and stored with a fidelity of 96.8% , surpassing the classical limit achievable by measure-and-prepare strategy. Our results demonstrate the first on-chip
quantum memory for telecom-band time-bin
qubits in TFLN, providing a key building block toward integrated
quantum registers and repeaters for scalable
quantum information processing.
Read the full abstract ▾
All authors Xiao-Jie Wang, Yong-Teng Wang, Zi-Wei Zhao, Yong-Min Li, Tian-Shu Yang
Optics
High-order mid-infrared nonlinear topological differentiator
Jixi Zhang, Kun Huang, Shina Liao et al. (+3 more)
High-order edge-enhanced imaging enables precise feature localization and effective background suppression, offering a powerful tool for real-time recognition and high-contrast visualization. Extending this capability to the mid-infrared (MIR) regime is particularly valuable for applications such as biomedical diagnostics, material inspection, and remote sensing, yet remains limited by inadequate spatial-frequency modulation fidelity and low detection sensitivity. Here, we demonstrate a high-sensitivity MIR upconversion differentiator operating at 3 $\mu$m, which achieves isotropic high-order edge enhancement by optically imprinting topological complex-amplitude patterns onto MIR
Fourier components via nonlinear parametric interaction.
Vortex transfer functions $t(k_r, \phi) \propto k_r^\ell e^{i\ell\phi}$ are precisely encoded on a phase-only spatial light modulator to enable tunable MIR differentiation from first- to fourth- order, with real-time switching at up to 60 Hz. Benefiting from a low-noise upconversion process and a single-
photon-sensitive silicon camera, the system achieves high-contrast edge imaging under low-light conditions. Experimental results confirm accurate edge extraction and background suppression for both amplitude and phase objects, hence underscoring its potential for noninvasive diagnostics and label-free material analysis.
Read the full abstract ▾
All authors Jixi Zhang, Kun Huang, Shina Liao, Zhuohang Wei, Jianan Fang, Heping Zeng
Accelerator Physics
Plastics and Composite Materials
Ana Teresa Perez Fontenla
Polymers and composite materials play an essential role in accelerator and detectors technology, with varying roles that range from electrical insulation and structural support to thermal management. This paper provides a general review of their key properties and classifications, including behaviour under demanding service conditions such as cryogenic operation and high radiation exposure. The paper addresses polymeric materials - their mechanical, thermal, and viscoelastic behaviour, and the effects of crystallinity and additives - alongside composite families, focusing on the characteristics of the
matrix and the types of reinforcement. CERN case studies illustrate how both
polymers and composites present opportunities and challenges in material selection. Examples include adhesives and structural composites for detectors, reinforced
alloys for collimators, and insulation for Nb$_3$Sn superconducting magnets, all emphasising the need to optimise material properties and interfaces to ensure the long-term reliability of components in accelerator facilities.
Read the full abstract ▾
Instrumentation and Detectors
Pulse shape discrimination for $\alpha$ event rejection in BEGe-type high-purity germanium detectors
Alex Biondi, Krzysztof Szczepaniec, Tomasz Mróz et al. (+2 more)
High-purity germanium detectors are widely used in rare-event searches due to their excellent energy resolution and extremely high intrinsic (
radio)purity. In experiments searching for neutrinoless double beta decay in $^{76}$Ge such as LEGEND, pulse shape discrimination is required to suppress multi-site $\gamma$ events. In this work, we investigate whether pulse shape discrimination classifiers trained exclusively on $\gamma$ ray data can be used to identify and reject $\alpha$ events, without the need for dedicated $\alpha$ training. In detectors such as LEGEND, the total number of registered $\alpha$ events over the experiment lifetime is expected to be insufficient to train dedicated classifiers, while still contributing to the background. Two approaches based on machine learning are studied: a multilayer perceptron and a projective likelihood classifier. The p+ surface of a point-contact semi-planar germanium detector was exposed to $^{209}$Po and $^{210}$Po sources deposited on a thin gold foil. Two measurement campaigns were performed, yielding $1.36\times10^{5}$ and $1.87\times10^{6}$ $\alpha$ events, respectively. Both classification methods achieve efficient separation of single-site and multi-site $\gamma$ events while strongly reducing the $\alpha$ component. The multilayer perceptron provides the best overall performance, with a signal-like event survival greater than 80%, a background-like event survival below 20%, and an $\alpha$-rejection factor exceeding $2.71\times10^{4}$. These results demonstrate that robust pulse shape discrimination for high-purity germanium detectors can be achieved using training information derived solely from $\gamma$ events, providing a promising strategy for next-generation neutrinoless double beta decay searches.
Read the full abstract ▾
All authors Alex Biondi, Krzysztof Szczepaniec, Tomasz Mróz, Marcin Misiaszek, Grzegorz Zuzel
Optics
Vectorial field reconstruction without detecting the field
Jonas Vasikonis, Sebastian Töpfer, Satyajeet Patil et al. (+2 more)
Vector beams, whose polarization varies across the transverse profile, are a central resource in structured-light optics and
quantum photonics. Their characterization, however, becomes challenging when the field lies in a spectral region for which efficient spatially resolving detectors are unavailable. Here we demonstrate the spatially resolved reconstruction of an undetected vector beam by exploiting induced coherence in a nonlinear interferometer. In this effect, indistinguishability between two down-conversion pathways allows information encoded in an undetected field to be read out through interference of its detected partner. A telecom-wavelength idler field acquires a spatially varying polarization transformation but is never directly detected. Instead, its local polarization information is inferred from single-
photon interference in the visible signal field, enabled by momentum correlations of the
photon pair. Using phase-shifting and off-axis
quantum holography with two polarization projections, we reconstruct the horizontal and vertical amplitudes and their relative phase across the beam profile, thereby recovering the full vectorial structure of the undetected field. We experimentally retrieve the polarization texture of an $m=2$ vector beam and compare multi-shot and single-shot reconstruction strategies. Our results extend imaging with undetected light from scalar objects to vectorial optical fields and open a route to polarization-sensitive sensing and state reconstruction in spectral regions that are difficult to access directly.
Read the full abstract ▾
All authors Jonas Vasikonis, Sebastian Töpfer, Satyajeet Patil, Jorge Fuenzalida, Markus Gräfe
Atomic Physics · Cross-listed from cond-mat.quant-gas
Site-selective preparation of two-dimensional dipolar quantum gases in an optical beat-note lattice
Niclas Höllrigl, Marian Kreyer, Rudolf Grimm et al. (+1 more)
High-resolution microscopy of two-dimensional dipolar
quantum gases requires selecting individual atomic layers, a task complicated for strongly
magnetic lanthanide atoms by the limited applicability of standard
magnetic-gradient techniques. We present an all-optical method for the deterministic spatial selection of single- and
bilayer samples of cold dipolar atoms using spatially selective parametric heating within a beat-note superlattice. By utilizing a high-resolution microscope objective as a common retroreflector for both optical frequency components, the
lattice planes are passively stabilized. This renders their positions exceptionally robust against experimental drifts and structure-borne vibrations, even eliminating the need for active
laser stabilization over millimeter-scale separations from the reflecting surface. We validate this approach by demonstrating the robust isolation of one or two atomic layers in precise coincidence with the focal plane of our objective. This enables future single-atom-resolved studies of long-range interacting systems.
Read the full abstract ▾
All authors Niclas Höllrigl, Marian Kreyer, Rudolf Grimm, Emil Kirilov
Atomic Physics · Cross-listed from quant-ph
Collective amplification and anisotropic narrowing of alignment signals in cesium vapor under strong spin exchange near zero magnetic field
Mikhail V. Petrenko and Anton K. Vershovskii
We present the results of an experimental study of the anomalous anisotropy of
alignment signals in cesium vapors under strong
spin-exchange conditions near zero
magnetic field with linearly polarized optical pumping. We show that the anisotropy of the Hanle resonances in the plane perpendicular to the pump beam increases with concentration: in one direction the widths remain broadened by
spin-exchange, whereas in the other they approach the
spin-exchange relaxation free limit. With a further increase in concentration, additional nonlinear effects arise, such as signal amplification, bistability, hysteresis, and
memory. To explain these effects we construct a illustrative theoretical model incorporating spontaneous polarization effects under strong
spin exchange conditions. The model qualitatively shows that the ultra-narrow
alignment resonances may originate from quadrupole anisotropy arising from the projection of spontaneous transverse orientation onto the detection axis. The unique properties of these resonances, such as their extremely small width and
magnetic field-controlled bistability with a long-term
memory effect, make them promising for use in
quantum sensing and information.
Read the full abstract ▾
Optics
Numerical speckle reduction for optical coherence tomography based on an analytical image formation model
Xibo Wang, Shuichi Makita, Nobuhisa Tateno et al. (+6 more)
Speckle is an intrinsic granular pattern that limits the effective resolution of optical coherence
tomography (OCT). We propose a numerical speckle reduction method using the "real part of a shifted complex conjugate product" (real-SCCP), which is a new image representation designed based on an analytical imaging model of OCT. In the real-SCCP image representation, the speckle can be fully numerically modulated after OCT signal acquisition. By averaging multiple SCCP images with different speckle realizations, the speckle is effectively reduced. Furthermore, this method enables clear visualization of structures in tumor spheroids and zebrafish eyes, and significantly outperforms conventional frame-averaging-based speckle reduction techniques.
Read the full abstract ▾
All authors Xibo Wang, Shuichi Makita, Nobuhisa Tateno, Suzuyo Komeda, Cunyou Bao, Atsuko Furukawa, Satoshi Matsusaka, Makoto Kobayashi, Yoshiaki Yasuno
Atmospheric and Oceanic Physics
State-resolved multimodal contributions to stratospheric polar vortex predictability
Shuo Yang, Dan Zhao, Tingting Xue et al. (+3 more)
The dynamical basis of stratospheric polar
vortex (SPV) predictability remains unclear, particularly the relative roles of persistence, structural variability, and cross-level coupling. Here we combine eigen microstate theory with mesoscopic Granger-causality analysis of ERA5 geopotential height fields to quantify the predictive contributions of eigen microstates. We show that short-term predictability is dominated by the persistence of the leading stratospheric state, whereas higher-order stratospheric structures and tropospheric variability provide additional predictive information at subseasonal leads. Including these additional states increases the all-winter 30-day prediction correlation from 0.24 to 0.33 and reduces forecast error. These contributions exhibit strong lead-time dependence and vary between winters with and without sudden stratospheric warmings. Part of this predictive information overlaps with that contained in preceding 100 hPa eddy heat flux, linking state-resolved predictability to wave-related circulation variability. Our results unify SPV predictability within a
multimodal, state-resolved framework and provide a physically interpretable pathway.
Read the full abstract ▾
All authors Shuo Yang, Dan Zhao, Tingting Xue, Chunhua Zeng, Yongwen Zhang, Xiaosong Chen
Atomic Physics
Momentum-space signatures of radial orbital nodes in XUV photoionization
Neha Kukreti and Amol R. Holkundkar
Photoelectron momentum distributions (PMDs) are widely used to probe light matter interactions, yet their angular features are generally assumed to be governed primarily by angular momentum selection rules. We show that the radial structure of the initial bound orbital can qualitatively modify PMD tilt beyond these con- ventional expectations. Using ab-initio time dependent Schrödinger equation calculations, we demonstrate this through comparative studies of single-
photon XUV ionization in neon and argon. While neon exhibits a smooth, monotonic increase in PMD tilt with wavelength, argon shows pronounced suppression and reversal near the wavelength where the d wave dipole
matrix element passes through a minimum. A partial wave analysis reveals that this non monotonic behaviour originates from a radial node induced minimum in the d wave dipole
matrix element, producing a rapid phase jump between interfering s and d wave ionization channels. We further show that atomic interferometric circular dichroism (AICD) provides a sensitive, experimentally accessible probe of this effect.
Read the full abstract ▾
Atomic Physics
$\Lambda$-enhanced gray-molasses loading and EIT cooling of neutral atoms in nanophotonic traps
Lucas Pache, Antoine Glicenstein, Philipp Schneeweiss et al. (+3 more)
Nanophotonic traps for cold atoms typically have trap volumes that are orders of magnitude smaller than, e.g., free-space optical tweezers. This makes efficient loading of these traps challenging, thereby limiting the total number of atoms coupled to the nanophotonic waveguide. Here, we demonstrate that $\Lambda$-enhanced gray-molasses ($\Lambda$GM) can substantially increase the number of trapped atoms in a nanofiber-based cold-atom setup. Specifically, we observe a six-fold increase in the number of loaded atoms compared to conventional red-detuned polarization gradient cooling. Despite the unusually small depth of our optical trap of only 24 $\mu$K, we load about 4000 individual Cesium atoms, achieving optical depths exceeding 140 and reaching the collisional blockade regime over a length of approximately 1 mm. After loading, we perform efficient EIT-assisted cooling that is found to increase the trap storage time to 400(9) ms. This is a 5-fold improvement over the passive storage time. Remarkably, EIT-cooling also works with two co-propagating nanofiber-guided light fields and requiries only about a few hundred picowatt of optical power. Our results provide an efficient method to boost both the number of loaded atoms and the storage time of nanophotonic atom traps.
Read the full abstract ▾
All authors Lucas Pache, Antoine Glicenstein, Philipp Schneeweiss, Jürgen Volz, Arno Rauschenbeutel, Riccardo Pennetta
Computational Physics · Cross-listed from cs.CE
Robust Matrix-Free Newton-Krylov Solvers via Automatic Differentiation
Marco Pasquale and Stefano Markidis
Jacobian-Free Newton-Krylov (JFNK) methods avoid forming the full Jacobian, but still require Jacobian-vector products, i.e., Gateaux derivatives of the nonlinear residual along Krylov directions. In standard Finite Differences (FD) formulations, these products are obtained by perturbing the Newton state and differencing residuals, making the linearization sensitive to round-off error and floating-point precision. This work evaluates the global impact of forward-mode Automatic Differentiation (AD) as a replacement for FD Jacobian-vector product in finite-precision JFNK solvers. The comparison keeps the discretization, Newton iteration, line search, Krylov methods, tolerances, and CPU/GPU backend fixed, only varying linearization strategy.
Benchmarks include Burgers dynamics, Su-Olson radiation
diffusion, reaction-
diffusion, and nonlinear time-harmonic Maxwell equations, each evaluated in different nonlinear regimes. By preventing degradation of the Krylov operator, AD accelerates computation by 2-3 orders of magnitude across both CPU and GPU architectures. More importantly, it drastically improves global solver robustness, achieving a minimum completion rate of 95%, compared to just 42% for FD. Ultimately, accurate Gateaux derivatives unify performance and accuracy in JFNK methods, making AD the optimal choice for stiff nonlinear and reduced-precision environments.
Read the full abstract ▾
Optics
Dipole light-matter interactions in the bispinor formalism
Sebastian Golat, Alex J. Vernon and Francisco J. Rodríguez-Fortuño
The conventional formulation of power absorption, optical forces, and torques on dipolar particles involve lenghty and cumbersome expressions that obscure their shared physical origin. We apply a bispinor formalism that unifies these disparate phenomena in a very general case including
chiral and nonreciprocal particles. This reveals that force, torque, absorbed power, and absorbed helicity rate can all be concisely expressed in terms of broken
symmetries, and leads to the fundamental inequalities that dipolar particles' cross-sections must satisfy. This framework uncovers profound connections normally hidden behind complex
algebra – for instance, pressure forces depend exclusively on the difference in linear momenta of different light components and the corresponding breaking of
symmetry by a particle, and optical
recoil forces depend exclusively on helicity cross sections – providing clarity, conciseness, and a powerful predictive tool for arbitrary dipole interactions.
Read the full abstract ▾
Optics
Threefold Efficiency Enhancement and Narrowed Nanoparticle Size Distribution in Laser Ablation of Gold in Water by GHz-Burst Irradiation
Maximilian Spellauge, Ramon Auer, Vincent Taebling et al. (+3 more)
Laser ablation in
liquids enables the synthesis of surfactant-free nanoparticles but remains limited in productivity due to intrinsic constraints imposed by the
liquid environment. These constraints include nonlinear optical losses, material redeposition, and cavitation bubble-induced shielding. Temporal intensity shaping of the incident
laser pulse offers a potential route to mitigate these limitations. Here, ultrashort GHz-burst ablation is applied to
laser ablation of gold in water. By distributing the pulse energy into a sequence of picosecond sub-pulses arriving within the nanosecond time window preceding cavitation bubble formation, GHz-burst irradiation enables energy delivery before the onset of bubble-induced shielding. This increases the threshold fluence for nonlinear losses and yields an ablation efficiency enhancement of up to a factor of three compared to single-pulse ablation. Importantly, this efficiency gain is not accompanied by an increase in cavitation bubble size or lifetime. In addition to enhanced efficiency, burst irradiation yields a twofold narrower nanoparticle size distribution. These results demonstrate that GHz-burst ablation is a promising approach to increase productivity while simultaneously improving nanoparticle quality.
Read the full abstract ▾
All authors Maximilian Spellauge, Ramon Auer, Vincent Taebling, Anna R. Ziefuss, Daniel J. Foerster, Heinz. P. Huber
Chemical Physics · Cross-listed from cs.LG
MPINeuralODE: Multiple-Initial-Condition Physics-Informed Neural ODEs for Globally Consistent Dynamical System Learning
Lake Yang, Antonio Malpica-Morales, Frank Ioannis Papadakis Wood et al. (+1 more)
Neural ordinary differential equations (Neural ODEs) often fit training trajectories while generalizing poorly to unseen initial conditions and long horizons. We propose MPINeuralODE, which combines a soft physics-informed residual with a Multiple-Initial-Condition (MIC) multiple-shooting curriculum whose ingredients are structurally complementary: the physics term anchors the vector-field magnitude on the support that MIC enlarges. We evaluate along three axes: out-of-sample error, long-horizon stability, and
Hamiltonian drift, which together expose whether the learned dynamics recover the underlying vector field. On Lotka-Volterra, MPINeuralODE achieves the lowest out-of-sample and long-horizon MSE among data-driven methods, with a 24% reduction over the baseline Neural ODE, while essentially matching the PINN ablation on
Hamiltonian drift.
Read the full abstract ▾
All authors Lake Yang, Antonio Malpica-Morales, Frank Ioannis Papadakis Wood, Serafim Kalliadasis
Physics and Society
Stochastic Modeling of Power-Grid Frequency Fluctuations in Low-Inertia Systems via a Gaussian-Core Potential and Superstatistics
Wanru Hao, Alessandro Lonardi and Christian Beck
Power grid frequency stability is fundamental to the secure operation of modern energy systems, yet the growing penetration of renewables and the associated reduction of system inertia have made frequency fluctuations increasingly non-Gaussian and difficult to model. Existing
stochastic models based on standard Ornstein–Uhlenbeck-type restoring terms yield a unimodal frequency distribution and therefore fail to reproduce the bimodal structure, central suppression, and heavy tails widely observed in empirical data. Here, we propose a data-driven
stochastic process that combines a Gaussian-core potential with superstatistical modeling, assuming slowly fluctuating coefficients for the grid dynamics. The Gaussian-core potential captures the potential barrier that gives rise to the characteristic double-peak structure of frequency distributions. Fitting the model to frequency data resolved at one-second intervals from the Great Britain grid, we find that the central barrier parameter increases substantially from 2020 to 2025 as the grid inertia progressively decreases. To simulate superstatistics, we use an Euler–Maruyama discretization and sample the drift amplitude from a lognormal distribution, thereby successfully reproducing empirical bimodality and heavy tails, as well as the autocorrelation decay. Our results establish a compact and interpretable model for characterizing the evolving complexity of low-inertia grid frequency dynamics.
Read the full abstract ▾
Instrumentation and Detectors
Development of Small-pitch, Ultra-thin 3D Silicon Sensors at USTC
Kuo Ma, De Zhang, Shengjia He et al. (+13 more)
We report on the development of 3D silicon sensors at the University of Science and Technology of China (USTC). The sensor involves columnar electrodes (5 um in diameter) of both doping types, etched from the same wafer side. The p+ electrodes pass through the epitaxial wafer, whereas the n+ electrodes stop at a short distance from the opposite side of the epitaxial wafer. Based on the current processing capacity, the sensors feature an ultra-thin active substrate (50 um) and a small pixel size of 50 um x 50 um or 25 um x 25 um. This R&D project aims to establish a sensor technology to simultaneously measure position and time information at the single-pixel level. The first fabrication run, using a merged layout containing both pixel sizes, has been completed. The design and fabrication of the sensors, followed by their characterization, including Current-Voltage (I-V) measurements and Sr-90 beta source measurements, are reported in this paper.
Read the full abstract ▾
All authors Kuo Ma, De Zhang, Shengjia He, Tian-ao Wang, Han Li, Yu Nie, Xiuxia Wang, Jinlan Peng, Zheng Liang, Xiang Li, Wenhua Shi, Manwen Liu, Chuan Liao, Zheng Li, Zebo Tang, Yanwen Liu
Optics
Robust High-Precision Time Transfer over 91-km Hollow-Core Fiber: Immunity to Dispersion and Nonlinearity
Bo Liu, Xinxing Guo, Jiang Chen et al. (+8 more)
To address the fundamental limitations imposed by chromatic dispersion and environmental susceptibility in standard single-mode fiber (SMF) for long-haul high-precision time transfer, we systematically explore the application potential of hollow-core fiber (HCF) through comparative experiments. We designed a bidirectional time transfer platform enabling direct comparison between HCF and SMF links across distances of 91 km, 68 km, and 54 km. We quantitatively characterize the impact of critical non-reciprocal error sources, specifically the optical Kerr effect and chromatic dispersion, under varying
laser power, wavelength drift, and environmental perturbations. Our results show that HCF exhibits significantly suppressed dispersion, with a mean coefficient of 3.4 ps per nm per km, and reduced environmental sensitivity compared with SMF. Notably, over the 91 km link, the HCF yields a signal-to-noise ratio (SNR) enhancement of more than 24 dB and confines the time deviation to less than 80 ps, which is nearly an order-of-magnitude improvement over SMF, where the time deviation exceeds 600 ps, while remaining nearly immune to power and wavelength fluctuations. Under 24 hour diurnal monitoring, the 68 km HCF link demonstrates strong robustness, with environment-induced time delay fluctuations of 776 ps, corresponding to only 24.5% of those in SMF, which reach 3166 ps. Consequently, the time transfer stability, evaluated by time deviation (TDEV), reaches 0.2 ps at an integration time of 1000 s, representing a twofold improvement over SMF. These findings validate HCF as a superior transmission medium with low latency, low nonlinearity, and high thermal stability, paving the way for next-generation ultra-stable, long-haul time-frequency distribution networks.
Read the full abstract ▾
All authors Bo Liu, Xinxing Guo, Jiang Chen, Huibo Hong, Qian Zhou, Xiang Zhang, Ru Yuan, Rongduo Lu, Tao Liu, Ruifang Dong, Shougang Zhang
Applied Physics
In-situ tunable superconducting diode: towards field-free operation with infinite nonreciprocity
Razmik A. Hovhannisyan, Taras Golod, Amirreza Lotfian et al. (+1 more)
Efficient, scalable, and
magnetic-field-free superconducting diodes are essential for future superconducting electronics; yet, despite significant efforts, such practical devices remain unrealized. The main challenge lies in achieving broad-range in-situ tunability, both for optimization and for achieving transistor-like operation. Here, we study diodes based on four-terminal niobium planar Josephson junctions. We show that the multiterminal structure eliminates the need for an external
magnetic field and enables essentially unrestricted in-situ tunability, along with reconfigurability of the diode polarity, leading to new functionality. For example, we demonstrate that such diodes can operate as Gauss
neurons via reentrant superconductivity. By deliberately tuning the junction parameters, we obtain effectively infinite nonreciprocity (within experimental resolution) leading to threshold-free ac-current rectification. Such technologically simple, reconfigurable, and broadly tunable diodes could be instrumental for future digital and neuromorphic computing.
Read the full abstract ▾
All authors Razmik A. Hovhannisyan, Taras Golod, Amirreza Lotfian, Vladimir M. Krasnov
Classical Physics
Acoustic Chirality
Alex J. Vernon and Konstantin Y. Bliokh
We reveal a previously unknown continuous
symmetry and conservation law in the equations of linear isotropic elasticity, which describe the chirality of elastic waves. We show that the integral chirality is determined by the population imbalance between right- and left-handed transverse
phonons, whereas the local chirality density generally involves both transverse and longitudinal wave components. We also introduce the related concepts of acoustic helicity and “false chirality”. The theory is illustrated with simple interference fields exhibiting distinct distributions of chirality,
spin angular momentum, and false chirality. Our results establish chirality as a fundamental property of elastic waves and provide a general theoretical framework for
chiral acoustic phenomena.
Read the full abstract ▾
Chemical Physics · Cross-listed from cond-mat.soft
Fluctuation-Dissipation Framework for Size-Dependent Surface Tension
Sergii Burian, Yevhenii Shportun, Liudmyla Klochko et al. (+3 more)
The size-dependent
liquid-vapor surface tension controls phase change, wetting, and transport at nanoscales, yet its first
curvature correction, the Tolman length, remains difficult to determine. We develop a thermodynamic and statistical-mechanical framework that relates this correction to bulk response properties of a one-component
liquid near
liquid-vapor coexistence. For curved interfaces, the analysis considers two local formulations of the same capillary-chemical balance, in excess pressures and in relative density deviations. For weakly compressible
liquids in the regime emphasized here, the adopted asymmetric density-based formulation is the practically relevant one, with finite-
curvature effects entering through vapor supersaturation under capillary
equilibrium. At coexistence, the planar-limit value of the same Tolman length reduces to a combination of the
liquid isothermal compressibility and its pressure derivative and can be recast as a bulk fluctuation-response observable of the homogeneous
liquid in the isothermal-isobaric ensemble. In this representation, the planar-limit coefficient is determined by second and third central moments of the volume distribution, equivalently by the pressure response of the relative fluctuation width. For water, homogeneous (N,P,T) simulations of SPC/E and TIP4P/2005 sample the bulk
liquid, not an explicit
liquid-vapor interface, and yield estimates near -0.7 Angstrom at 300 K. An independent evaluation based on the IAPWS-IF97 industrial formulation gives -0.713 +/- 0.004 Angstrom at the same coexistence state and predicts a weakly nonmonotonic temperature dependence along coexistence. Beyond water, the framework applies to other one-component
liquids in regimes where an accurate thermal equation of state or sufficiently converged bulk volume statistics are available.
Read the full abstract ▾
All authors Sergii Burian, Yevhenii Shportun, Liudmyla Klochko, Leonid Bulavin, Dmytro Gavryushenko, Mykola Isaiev
Biological Physics
A hyperbolic cell cycle law for early embryonic developmental timing
Adrián Aguirre-Tamaral, Johanna Royer, Magdalena Schindler-Johnson et al. (+4 more)
Across metazoans, early embryos exhibit a strikingly conserved slowing down of their
cell duplication speed, despite widely varying developmental paces and underlying molecular mechanisms. Here we show that this common behavior arises because early development unfolds along a biochemical rather than a chronological timescale, resulting from the coupling of finite maternal resource consumption to the Michaelis-Menten-like kinetics governing the rates of the biochemical reactions involved in
cell duplication. This leads to a
hyperbolic growth of the
Cell Cycle Length (CCL), approaching a mathematical singularity, which would correspond to developmental arrest. Data from a wide range of organisms – cnidarians, nematodes, arthropods, molluscs, echinoderms, tunicates, amphibians, and fish – collapse on a single curve, quantitatively capturing not only a universal CCL dynamical behaviour, but also key hallmarks of early metazoan development, including
cell-number temporal
evolution, the dependency of CCL on
cell size, and, remarkably, gastrulation timing at the predicted singularity. Crucially, experimental modulation of resource availability and consumption rates validate the model and further demonstrate that a source of heterochrony in early development is an altered biochemical timescale of resource depletion. Overall, this work reveals resource consumption rates as a fundamental mechanism driving developmental timing in early embryogenesis across species.
Read the full abstract ▾
All authors Adrián Aguirre-Tamaral, Johanna Royer, Magdalena Schindler-Johnson, Jun-Ru Lee, Daniel R. Amor, Nicoletta I. Petridou, Bernat Corominas-Murtra
Computational Physics · Cross-listed from cond-mat.mtrl-sci
Conditional probability density functional theory for solids
Peiwei You, Ryan Pederson, Kieron Burke et al. (+1 more)
The recently developed conditional probability density functional theory (CP-DFT) yields direct access to the exchange-correlation hole of a system, an important correlation function that is not available in standard DFT. We present the first results for extended materials with periodic boundary conditions. We validate CP-DFT for weakly correlated Na and Si. We apply it to a stretched hydrogen chain, the prototype of strong correlation. When applied to the Kagome material CsV$_3$Sb$_5$, we find $d$-orbital correlations that are missing in standard DFT, implying an enhanced finding probability between two separated electrons and a local charge density wave related modulation.
Read the full abstract ▾
All authors Peiwei You, Ryan Pederson, Kieron Burke, E. K. U. Gross
Optics
On-chip 1 TOPS Hyperdimensional Photonic Tensor Core using a WDM Silicon Photonic Coherent Crossbar
S. Kovaios, I. Roumpos, A. Tsakyridis et al. (+4 more)
We demonstrate an on-chip 0.96 TOPS hyperdimensional photonic tensor core by utilizing a time-spacewavelength multiplexed silicon photonic Crossbar (Xbar). The novel architecture relies on serializing the large
matrix-vector or tensor-vector products by unfolding multiply and accumulation operations over time domain, while simultaneously distributing the computational workload over different spatial and wavelength channels. We experimentally demonstrate the operation of a 4-channel 2-input TSWDM Xbar that incorporates 56 GHz electroabsorption modulators (EAMs) and 4-channel integrated multiplexing stages. Its successful operation as a 4x2x1 tensorvector multiplication unit demonstrated an average error of 3.9%. Its performance as a photonic AI accelerator was also evaluated in the classification task of the Iris
dataset, presenting experimental accuracies of 93.3% at data rates between 4x10 and 4x30 GBd, reaching 83.3% when the data rate increases to 4x60 GBd. Finally, we discuss the TSWDM Xbar scalability potential, revealing that the inclusion of a WDM scheme in the SDM architecture reduces the operating
laser power, feasibly boosting the potential of constructing photonic accelerators with computational throughput in the POPS regime.
Read the full abstract ▾
All authors S. Kovaios, I. Roumpos, A. Tsakyridis, M. Moralis-Pegios, D. Lazovsky, K. Vyrsokinos, N. Pleros
Instrumentation and Detectors
Stable Charge Collection and Sub-45 ps Time Resolution in a 4H-SiC PIN Detector Irradiated With Low Fluence 16.5 MeV/u Ta Ions
Jingxuan He, Congcong Wang, Yi Zhan et al. (+3 more)
A silicon carbide PIN detector was fabricated and its radiation tolerance under Ta heavy ion irradiation of 2370 MeV was evaluated. Its electrical properties, charge collection performance and time resolution of $\beta$-particles ($^{90}$Sr) are reported. The leakage currents for unirradiated and irradiated 4H-SiC PIN detectors are $1.47 \times 10^{-10}$~A @ 300 V and 1.49~$\times$ 10$^{-10}$A@ 300 V. The effective doping concentrations for unirradiated and irradiated 4H-SiC PIN detectors are $6.23\times 10^{13}$~cm$^{-3}$ and $6.13\times 10^{13}$~cm$^{-3}$. The irradiated detector exhibits good electrical performance and stable device architecture. The 4H-SiC PIN detector exhibits a charge collection efficiency (CCE) of 99.24% under Ta Heavy Ion Irradiation. The time resolutions of the detector before and after irradiation are 40 ps and 45 ps, respectively. Experimental results indicate that the CCE and time resolution performance exhibit good stability before and after irradiation. These results demonstrate stable performance under Ta heavy ion irradiation, highlighting the detectors potential for radiation-hard applications in high-energy physics, space missions, and
nuclear reactor monitoring.
Read the full abstract ▾
All authors Jingxuan He, Congcong Wang, Yi Zhan, Zhenyu Jiang, Xiyuan Zhang, Xin Shi
Optics · Cross-listed from cond-mat.quant-gas
Observation of an aperiodic polariton monotile
Sergey Alyatkin, Yaroslav V. Kartashov, Kirill Sitnik et al. (+2 more)
A plethora of unconventional localization phenomena and fractal features of linear spectrum observed in quasiperiodic structures have been accompanied by a long-standing quest for the geometrical elements and structures that permit tilings of the plane, but only in a non-periodic manner. Until 2024, it was believed that such quasiperiodic structures, or quasicrystals, could only be composed of at least two different tiles. Surprisingly, a newly discovered class of quasicrystals requires only one elementary monotile. However, its physical realization and study of propagating coherent excitations in this novel setting remained elusive. Here we optically sculpt aperiodic quasicrystals composed of "einstein" monotiles in an inorganic microcavity and observe nontrivial relative phases of the
exciton-polariton condensates nonresonantly excited at the vertices of each monotile. Utilizing energy-resolved
tomography in momentum-space, we reveal the formation of distinct Bragg peaks with six-fold
symmetry and Dirac-like spectral fingerprints, intrinsic to the underlying
graphene-like structure, while interferometric phase reconstruction shows a nontrivial synchronization pattern distinct from both periodic triangular
lattices and Penrose quasicrystals. Our work demonstrates that monotiles can be converted into a programmable driven-dissipative artificial material, where long-range coherence coexists with enforced
geometric aperiodicity, producing synchronization and spectral responses distinct from both periodic and conventional quasicrystalline tilings.
Read the full abstract ▾
All authors Sergey Alyatkin, Yaroslav V. Kartashov, Kirill Sitnik, Philipp Grigoryev, Pavlos G. Lagoudakis
Instrumentation and Detectors
Development of a sub-100 ps Time-of-Flight detector with SiPM-readout scintillator for measurement of cosmic muon velocity
Ziyi Yang, Xiyang Wang, Shiming Zou et al. (+5 more)
Accurate Time-of-Flight (TOF) measurement with sub-100 picosecond resolution is a critical requirement for particle identification in future high-energy physics experiments, such as the Belle II $K_{L}$ and
Muon (KLM) detector upgrade. Achieving this precision with large-area Silicon Photomultipliers (SiPMs) is challenging due to the inherent junction capacitance, which degrades signal rise time. In this work, we developed and evaluated a high-time-resolution
cosmic ray detector based on plastic scintillators and customized SiPM arrays. To optimize the readout for block-shaped scintillators, we systematically compared different sensor
topologies. We demonstrate that a multi-face readout
topology, utilizing low-capacitance 4-series (4S) SiPM modules coupled to four faces of the scintillator, achieves an excellent coincidence time resolution of approximately 68 ps, outperforming the $\sim$100 ps resolution of the concentrated 4-series 3-parallel (4S3P) hybrid
topology. Furthermore, to validate the system's practical performance, we successfully measured well-known
cosmic ray observables, specifically the relativistic
muon velocity via TOF reconstruction. These results highlight the potential of the multi-face 4S configuration as a high-precision solution for future TOF detector upgrades.
Read the full abstract ▾
All authors Ziyi Yang, Xiyang Wang, Shiming Zou, Ting Wang, Kairui Huang, Wanyi Zhuang, Yicheng Pu, Xiaolong Wang
Biological Physics
Onsager-variational formulation of diffuse-domain methods for computational modeling of microscale fluid-structure interactions
Xinpeng Xu
Direct numerical simulation of microscale fluid–structure interactions in multicomponent and multiphase flows requires methods that can represent moving boundaries together with fields constrained to evolving interfaces. Diffuse-domain methods (DDMs) address this
geometric difficulty by replacing sharp surfaces with diffuse volumetric representations on regular computational domains. Here we formulate DDMs using Onsager's variational principle. Instead of extending sharp-interface equations and boundary conditions term by term, we embed sharp-surface free-energy and dissipation functionals into the bulk through a diffuse surface delta density and derive the governing equations from the Rayleighian. The framework distinguishes balance-law fields, internal nonconserved order parameters, and kinematic or constitutive rate variables. It also clarifies a key moving-surface distinction: conserved surface densities are transported by the full material surface velocity, whereas explicitly tangential vector and tensor internal variables require projected objective or co-rotational rates within their admissible tangential state spaces. For scalar transport on rigid and deformable interfaces, and for interfacial hydrodynamics near rigid walls, the formulation recovers established DDM models and their sharp-interface limits. The same variational construction yields coupled diffuse-domain models for multicomponent deformable vesicles with surface viscosity, tangential slip, and finite areal compressibility, and for active shells carrying chemical and tangential vector order. These results provide a unified route to thermodynamically consistent passive DDMs for interfacial and surface dynamics, while allowing active stresses through active work power. The framework is relevant to soft matter, microfluidic interfaces, biological membranes, and morphogenetic surface dynamics.
Read the full abstract ▾
Fluid Dynamics
Influence of Prandtl number on heat transfer over a permeable wall
Wojciech Sadowski, Hakan Demir and Francesca di Mare
The work considers a fully turbulent flow with heat transfer in a channel half-filled with an array of cubes based on the work of Breugem and Boersma (2005) and Chandesris et al. (2013), at $\mathrm{Re}_\mathrm{bulk} = 5485$ and three different Prandtl numbers, $\mathrm{Pr} = 0.71, 0.1, 0.05$. The temperature is modelled as a passive scalar and two different boundary condition configurations are simulated. The influence of the Prandtl number on the mean temperature, its variance and the terms of the temperature budget is highlighted, including the analysis of the distribution and relative importance of the turbulent heat transfer, molecular
diffusion, tortuosity and Brinkman terms near the porous-fluid interface. The latter two has been found to be insignificant for the highest $\mathrm{Pr}$. A set of terms, typically neglected during the upscaling procedure (related to the Taylor expansion of the filtered variables), is analysed for the first time for the turbulent heat transfer at the porous-fluid interface, and are found to be significant at low $\mathrm{Pr}$. The upscaled fields are evaluated with three different kernels forming cellular average, linear (i.e., tent kernel), quadratic and cubic, and the influence of the chosen filter is additionally studied.
Read the full abstract ▾
Optics
Burst-Mode Ultrafast Laser Welding of Sapphire and Invar Alloy Across Large Interfacial Gaps up to 10 $\mu$m
Yuxuan Li, Nan Li, Yu Wang et al. (+7 more)
Achieving reliable joining between transparent materials and metals under non-optical-contact conditions remains challenging due to limited energy coupling and uncontrolled interfacial reaction across $\mu$m-scale gaps. Burst-mode ultrafast
lasers provide a potential solution for large-gap welding through temporally distributed energy deposition. However, the underlying interaction mechanisms and achievable joining limits remain unclear. In this study, burst-mode ultrafast
laser welding of sapphire to Invar
alloy was investigated under controlled interfacial gaps from 3 to 10 $\mu$m. Cross-sectional microscopy, elemental mapping, white-light interferometry, and shear testing were employed to analyze joint morphology, elemental distribution, fracture behavior, and mechanical performance.After optimization of the processing parameters for burst-mode ultrafast
laser welding, the interfacial morphological
evolution and joint strength under different gap conditions were systematically investigated. At a 3 $\mu$m gap, cyclic thermal stresses induced by burst pulses generate transverse micro-crack networks in sapphire, accompanied by a reduction in joint strength with increasing sub-pulse numbers. Notably, at a 10 $\mu$m gap, where single-pulse welding fails, burst-mode ultrafast
laser welding enables interfacial bridging with a maximum shear strength of 6.3 MPa, representing the highest level among published studies.These results indicate a gap-dependent
evolution in burst-mode welding behavior governed by crack formation and energy accumulation. This study provides an important theoretical basis and practical guidance for achieving high-performance joining of dissimilar materials under large gap conditions.
Read the full abstract ▾
All authors Yuxuan Li, Nan Li, Yu Wang, Yitong Chen, Rong Su, Qingwei Zhang, Rongxian Wen, Guochang Jiang, Feng Chen, Shanglu Yang