Optics
Observation of Replica Symmetry Breaking in Filamentation and Multifilamentation
André C. A. Siqueira, Guillermo Palacios, Jessica E. Q. Bautista et al. (+4 more)
We report the experimental observation and characterization of Replica
Symmetry Breaking (RSB) manifestation while analyzing the transverse intensity profile of pulses in filamentation experiments using sapphire
crystal and distilled water, excited by a femtosecond
laser centered at 800 nm. The RSB arises from the competition between self-focusing and
plasma defocusing, subject to local fluctuations in the nonlinear refractive index generated by
plasma via multiphoton excitation, which subsequently promotes frustration among modes. Our results confirm the existence of glassy-like photonic states not only in multifilamentation, as previously reported [W. Ettoumi, J. Kasparian, and J. Wolf, "
Spin-glass model governs
laser multiple filamentation," Phys. Rev. Lett., vol. 115, no. 3, pp. 033902, 2015], but also in the generation of a single filament and in filamentation accompanied by conical emission. These findings improve the understanding of statistical nonlinear optics by establishing connections with magnetism and highlighting the glassy-like behavior of light in the context of ultrafast optical phenomena.
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All authors André C. A. Siqueira, Guillermo Palacios, Jessica E. Q. Bautista, Anderson M. Amaral, Albert S. Reyna, Edilson L. Falcão-Filho, Cid B. de Araújo
Applied Physics
Pendellösung length-scale neutron and X-ray interferometry
Owen Lailey, Alexandre Boutot, David G. Cory et al. (+12 more)
Neutron and X-ray perfect-
crystal interferometers (PCIs) are powerful platforms for studies of fundamental physics and phase-contrast imaging. Further enhancing several PCI capabilities requires reducing
crystal blade thickness to the micron scale, which minimizes dynamical-diffraction image blur, permits operation in the pendellösung regime where blade thickness controls beam splitting, and reduces absorption for simultaneous
neutron and X-ray operation. However, fabricating multiple
crystal blades with identical micrometer-scale thicknesses over centimeter-scale areas remains a major challenge. Here, using a non-etching sub-micron fabrication technique, we demonstrate silicon triple-Laue interferometers with equal-blade-thicknesses of 110 $\mu$m and 350 $\mu$m, operated with both
neutrons and X-rays. These devices are the thinnest PCIs realized to date, enabling a factor-of-six reduction in dynamical-diffraction beam spreading for improved phase-contrast imaging, while reaching the single pendellösung length regime in which
crystal thickness provides an experimentally accessible control parameter for engineered
quantum-optical beam splitting of plane-wave inputs. These results motivate multi-blade PCI designs utilizing identical half-pendellösung
crystal lamellae that are proposed for
neutron spin–orbit and electric dipole moment measurements.
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All authors Owen Lailey, Alexandre Boutot, David G. Cory, Joseph P. Cotter, Vishal Dhamgaye, Tao Hong, Michael G. Huber, Young-June Kim, Winfried Kockelmann, Jeremy W. Paster, Dusan Sarenac, Kawal Sawhney, Naume Shentevski, Ivar Taminiau, Dmitry A. Pushin
Classical Physics
Bypass transition under wall cooling over a flat plate with an elliptical leading edge
Adèle Veilleux, Hugues Deniau and Olivier Vermeersch
This study uses wall-resolved large-eddy simulations to investigate bypass transition in a flat-plate boundary layer subjected to free-stream
turbulence. Two thermal configurations are considered: an adiabatic wall and a uniformly cooled wall. The plate geometry includes an elliptic leading edge and is designed for direct experimental reproduction, providing a framework for future numerical-experimental comparisons. The resolved leading edge allows direct examination of the early stages of bypass transition. Both simulations recover the classical sequence of receptivity,
vortex tilting, lift-up, streak amplification, secondary instability and turbulent-spot growth. The wall-normal transport term is identified as a precursor of streak formation, while shear sheltering is quantified and linked to the frequency-dependent penetration of free-stream disturbances into the boundary layer. Wall cooling does not modify the bypass-transition mechanisms nor the onset location of transition. Instead, it generates thermal streaks alongside the velocity streaks and shifts the latter slightly closer to the wall, consistent with optimal-perturbation predictions. The velocity streaks retain similar amplitudes, growth rates and spanwise spacings in both thermal conditions. A conditional analysis reveals a pronounced asymmetry between high- and low-velocity streaks. Although breakdown is systematically observed within low-velocity streaks, the strongest pre-transitional
evolution occurs within the high-velocity streak population, which undergoes significant amplification and a progressive displacement towards the wall before the onset of intermittency. These observations suggest that high-velocity streaks may actively contribute to the reorganisation of the streak field leading to secondary instability and breakdown.
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Optics
Real-Time Doppler-Frequency Measurement and Frequency-Pulling Suppression in Arm-locking
Zheng-Rong Xiang, Jun Ke, Tian-Chi Zhu et al. (+3 more)
Arm-locking is an important technique for suppressing
laser frequency noise in space-based gravitational-wave detection. However, stronger noise suppression inevitably increases the magnitude of frequency pulling, thereby prolonging the lock-acquisition time and increasing the risk of system instability. To address this issue, this paper proposes a real-time Doppler-frequency measurement and frequency-pulling suppression method based on a linear-quadratic-gaussian controller. To achieve a balance between noise suppression and pulling suppression, a time-varying control strategy is adopted. At the initial stage of the time-varying control process, the primary objective is to rapidly limit frequency pulling. Subsequently, the level of pulling suppression is gradually relaxed while the capability for
laser frequency-noise suppression is progressively enhanced, so that the residual frequency noise satisfies the time-delay interferometry (TDI) requirement by the end of the transition. Comprehensive performance simulations are conducted for several arm-locking configurations. The results show that the proposed suppressor can reduce frequency pulling within approximately 1000 s while limiting its magnitude to below 100 MHz, thereby eliminating the need for the conventional Doppler frequency pre-estimation stage. When a Fabry-Perot
laser is used, the amplitude spectral density (ASD) of the closed-loop
laser frequency noise meets the requirements of second-generation and first-generation TDI after 2000 s and 9200 s of closed-loop operation, respectively. These results demonstrate that the proposed suppressor provides both rapid frequency-pulling suppression and a high level of
laser frequency-noise suppression. This new method provide a feasible way for rapid acquisition and locking of arm-locking.
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All authors Zheng-Rong Xiang, Jun Ke, Tian-Chi Zhu, Hao-Xin Xu, Cheng-Gang Shao, Jie Luo
Optics
Replica Symmetry Breaking in the Quasi Mode Locked Regime of Titanium Sapphire Lasers
Nicolas P. Alves, Ricardo V. M. de Almeida Filho, Isaac C. Nunes et al. (+4 more)
Recent observations of replica
symmetry breaking (RSB) in ytterbium-based mode-locked fiber
lasers have revealed glassy behavior in the quasi-mode-locked (QML) regime. Here, we investigate whether this behavior is restricted to a specific
laser implementation or represents a more general feature of mode-locked systems. By analyzing statistical correlations of spectral intensity fluctuations through the Parisi overlap and Pearson correlation parameters, we study two Titanium:sapphire
laser systems: a homemade cavity and a commercial
laser. In both cases, clear signatures of RSB are observed in the QML regime, while replica-symmetric behavior is recovered in the amplified spontaneous emission (ASE) and standard mode-locked (SML) regimes. These results demonstrate the occurrence of RSB in Titanium:sapphire
lasers and support the interpretation of the QML regime as a photonic glassy phase. Together with previous observations in ytterbium-based fiber
lasers, these findings suggest that the connection between QML dynamics and RSB may be a general feature of mode-locked
laser systems.
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All authors Nicolas P. Alves, Ricardo V. M. de Almeida Filho, Isaac C. Nunes, Gleison S. Bezerra, Cid B. de Araújo, Marcio H. G. de Miranda, André C. A. Siqueira
Geophysics
Direction-Aware Masked Pretraining on 3D Seismic Data with Transfer to Cross-Area Acoustic Impedance Inversion
Man Tang, Zhaoyun Zong, Diqiong Jiang et al. (+2 more)
Seismic feature extraction and acoustic impedance inversion are important for subsurface characterisation, but sparse well-log data limit the generalisation of data-driven inversion models across different areas. Self-supervised masked pretraining offers a way to exploit large volumes of unlabelled seismic data; however, conventional approaches often overlook the directional characteristics of 3D seismic data. We propose a direction-aware masked autoencoder (DA-MAE) that distinguishes lateral reflector structure from vertical waveform characteristics in 3D post-stack data. The framework incorporates this distinction into
token representation, masking geometry, and reconstruction constraints on reflector continuity and waveform fidelity. We evaluate DA-MAE through masked reconstruction on an independent field survey and cross-area acoustic impedance inversion using two additional field areas. Reconstruction experiments show that performance is more sensitive to lateral
token resolution than to moderate changes in vertical patch length, and that increasing encoder capacity does not fully compensate for coarse tokenization. Moreover, the preferred
token scales and masking strategies vary between reconstruction and inversion, suggesting that reconstruction fidelity alone is not a reliable indicator of transferability. In cross-area inversion, the pretrained representations remain effective in the target area and improve impedance prediction, demonstrating their transferability across different seismic surveys. These results provide practical guidance for seismic-specific masked pretraining and its application to acoustic impedance inversion.
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All authors Man Tang, Zhaoyun Zong, Diqiong Jiang, Gen Li, Jiayun Li
Optics
Ultralow-power, high-speed programmable Si photonic circuits with InGaAsP membrane
Tomohiro Akazawa, Rui Tang, Hanzhi Tang et al. (+6 more)
Programmable photonic
circuits have emerged as a promising platform for applications ranging from optical communications to artificial-intelligence computing and
quantum information processing, but their scaling is fundamentally constrained by their essential building block, the optical phase shifter. Existing phase-shifter technologies face inherent trade-offs among power consumption, operating speed, modulation efficiency, optical loss, and thermal crosstalk, making it challenging to realize high-performance, large-scale programmable photonic
circuits. Here, we present a programmable photonic
circuit based on InGaAsP/Si hybrid metal-oxide-
semiconductor (MOS) phase shifters that combines ultralow power consumption, high-speed operation, high modulation efficiency, low optical loss and negligible thermal crosstalk. The phase shifters combine the low leakage current of a MOS capacitor with the strong carrier-induced refractive-index modulation of an InGaAsP membrane, achieving a static power consumption below 30 fW/$\pi$, a switching time of 555 ps, a phase-modulation efficiency ($V_\pi L$) of 0.13 Vcm and a carrier-induced excess insertion loss of only 0.20 dB/$\pi$. We integrate these phase shifters into a programmable Mach-Zehnder interferometer mesh and demonstrate optical switching and programmable
unitary transformations, while maintaining femtowatt-level static power consumption across integrated phase shifters. We further demonstrate
circuit-level operation with negligible thermal crosstalk, addressing a major obstacle to densely integrated programmable photonic
circuits. These results establish a foundation for scalable, high-performance programmable photonic systems for next-generation signal processing and computation.
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All authors Tomohiro Akazawa, Rui Tang, Hanzhi Tang, Makoto Okano, Yangyang Wan, Nobuyuki Matsuda, Kasidit Toprasertpong, Shinichi Takagi, Mitsuru Takenaka
Chemical Physics
Benchmarking higher-ranking multipoles and polarizability tensors for small molecular systems
Bruno V. von Bruening and Alston J. Misquitta
Molecular properties govern how molecules interact with one another or external fields. Accurate molecular properties are essential for constructing intermolecular interaction models, and to achieve high accuracy we need to go beyond leading-order (dipolar) terms. This work presents CCSD(T) references for 73 small non-
spin-polarized molecules for molecular dipole and quadrupole moments, and dipole-dipole and quadrupole-quadrupole polarizabilities. Using these results, we provide a holistic performance analysis of molecular properties computed with HF, MP2, CCSD, and a wide range of density-functional methods. Additionally, we investigate in detail what levels of basis sets are required to simultaneously describe all properties in the data set. The best-performing density functionals for all four properties are the asymptotically cor- rected hybrid GGAs B97-3-AC, closely followed by PBE0-AC. Surprisingly, modern meta- GGAs and range-separated functionals perform inconsistently, with large errors in the quadrupo- lar properties. These results have direct implications for methods for intermolecular interac- tions, such as
symmetry-adapted perturbation theory based on density functional theory, or for the quality of properties and interactions in machine-learning
datasets. Finally, for DFT methods, the Jensen aug-pcseg-2 basis set is a computationally efficient alternative to more established basis sets, but for generating correlated references, third-row elements benefit from core polarization, and double augmentation is strictly necessary for quadrupole-quadrupole polarizabilities.
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Chemical Physics · Cross-listed from quant-ph
An Exact Operator Formulation of Statistical Quasiparticle Theory for Nonlinear System-Bath Coupling
Yu Su and Yao Wang
We develop an operator formulation of statistical quasiparticle theory for open
quantum systems with nonlinear system-bath coupling, extending beyond the linear coupling setting of the standard Gaussian influence functional formulation. For Gaussian baths, the statistical quasiparticles, termed dissipatons, are explicitly constructed as collective operators in the thermofield bath space. Our construction provides a microscopic operator basis for the dissipaton
algebra and generates hierarchical equations of motion directly from the Liouville equation. Nonlinear interactions are incorporated through a recursive generalized Wick's
theorem, enabling automatic generation of hierarchical equations for
polynomial couplings. The resulting framework connects explicit bath operator representations to nonperturbative, non-Markovian dynamics and unifies the treatment of linear and nonlinear system-bath interactions.
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Chemical Physics
Composition-Dependent Self-Diffusion Coefficients in Liquid Mixtures from Hybrid Machine Learning
Jens Wagner, Thomas Specht, Hans Hasse et al. (+1 more)
Self-
diffusion coefficients are key descriptors of molecular mobility, yet experimental data remain scarce, highlighting the need for reliable prediction methods. In previous work, we introduced the hybrid Enhanced Stokes-Einstein (ESE) model, which advanced the state of the art in the physically consistent prediction of self-
diffusion coefficients of solutes at infinite dilution in pure solvents by integrating the Stokes-Einstein equation with machine learning (ML). Here, we extend this approach to concentration-dependent self-
diffusion coefficients and multicomponent solvents with HADES. This hybrid architecture leverages a deep-set neural network to connect pure-component and mixture prediction within a single framework. HADES predicts self-
diffusion coefficients in
liquid mixtures with any number of components at any composition and temperature. The only required inputs are SMILES-encoded molecular structures of the components and the pure-component viscosities, making the method broadly applicable. Trained and evaluated on a comprehensive
dataset of 2526 data points for 600 systems, HADES significantly outperforms
benchmark prediction methods. The trained model and its source code are fully disclosed, and the application is available via an interactive website https://ml-prop.mv.rptu.de/.
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All authors Jens Wagner, Thomas Specht, Hans Hasse, Fabian Jirasek
Atomic Physics
Vector Measurements Using Integrated Radio Frequency Atomic Magnetometers
Ayse Marasli, Thomas W. Kornack, D. Casey Oware et al. (+1 more)
We demonstrate reconstruction of three-dimensional
radio-frequency (RF)
magnetic-field vectors using a pair of integrated RF atomic magnetometers operated with orthogonal bias-field orientations. A theoretical and experimental analysis identifies a phase-ambiguity dead band that limits reconstruction when the two sensor responses become nearly identical. Measurements performed in an unshielded laboratory environment demonstrate accurate reconstruction of RF
magnetic-field orientations and validate the predicted dependence of reconstruction accuracy on signal imbalance. These results establish integrated RF atomic magnetometers as a compact and sensitive platform for directional RF
magnetic-field sensing, particularly at low frequencies, and provide a foundation for portable source-localization and field-mapping applications.
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All authors Ayse Marasli, Thomas W. Kornack, D. Casey Oware, Karen L. Sauer
Atomic Physics · Cross-listed from quant-ph
Collective advantage from a minimal record in a quantum information engine
Kangqiao Liu, Jie Gu and Deyou Chen
For a single particle, a
quantum information engine can turn measurement fluctuations into transport by raising a barrier behind the particle each time its position is measured. When many particles are present, the barrier still depends on just one number, the position of the leftmost particle, so we let the demon measure that order statistic and nothing else. A demon that resolves every position instead pays a record
entropy that grows with particle number, even though the extra distinctions never change where the barrier is placed. We show that the coarser measurement supplies an energy that is bounded independently of particle number, and that this bound yields a ceiling on the record
entropy that falls as the filling increases. At the same tilt, the collective engine then delivers $44\%$ more work per recorded nat than independent single-particle engines, each with its own optimized cycle time and each running at equal or greater power per particle. Pauli blocking ends this advantage once the accessible region just above the wall fills. We also evaluate the coherence that the coarse measurement leaves behind, and the cost of placing the barrier imprecisely.
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Physics and Society
Unused power surge compromises U.S. road vehicles sustainability
Hugues Perraut, Joseph Le Bihan, Eric Herbert et al. (+1 more)
Material and energy flows underpin sociotechnical metabolism. However, despite growing sustainability concerns over expanding material stocks and declining stock productivity, the link between material use and energy consumption remains poorly understood. This gap reflects a limited distinction between structures and the activity they enable, and the lack of quantification of the installed power of energy consuming structures. Here we reconstruct the long-term growth dynamics of U.S. road vehicles, distinguishing professional and consumer assets. We show that installed power, mass, and fuel energy use follow divergent patterns within and across vehicle categories. By introducing the usage factor as a metric linking structure to activity, we quantify decoupling mechanisms such as engine oversizing and fleet redundancy, which drive up material immobilization. As electrification requires large-scale fleet replacement, our findings highlight that avoiding power oversized vehicles could reduce material demand, emphasizing the need to account for structure-activity decoupling in energy transition policies.
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All authors Hugues Perraut, Joseph Le Bihan, Eric Herbert, Petros Chatzimpiros
Biological Physics · Cross-listed from cond-mat.soft
Phase diagram morphology shapes droplet propulsion in chemical gradients
Stefan Köstler, Malcolm Steen and David Zwicker
Droplets in complex environments often encounter compositional gradients that drive their propulsion. For example, surfactant gradients induce surface-tension-driven propulsion via the Marangoni effect. Here, we show that such propulsion emerges generically, even in the absence of surfactants. Employing a thin-interface approximation, we derive a compact expression for the droplet velocity in terms of droplet size, viscosity, the sensitivity of surface tension to a regulating component, and the chemical potential gradient of that component. Our theory reveals that droplets move toward regions of lower stability, as encoded in the morphology of the phase diagram, particularly near critical points. Numerical simulations confirm these results, which establish a general route to predicting and designing droplet motility from the phase behavior of complex fluids.
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Plasma Physics · Cross-listed from astro-ph.SR
Oblique kink waves in solar coronal streamers
Aleksandr V. Rubtsov, Valery M. Nakariakov, Dmitri Yu. Klimushkin et al. (+1 more)
Coronal streamer kink waves excited by an impact of coronal mass ejections (CMEs) are routinely used to estimate the coronal Alfvén speed. These estimates generally assume wave propagation parallel to the
equilibrium magnetic field directed radially outward to the Sun, in the plane of the sky. However, the geometry of CME impacts naturally allows for oblique propagation. We investigate the properties of obliquely propagating kink waves guided by a
plasma slab with a central current sheet representing a coronal streamer stalk. We consider both cold and warm streamer
plasmas and analyse influence of propagation obliquity on wave dispersion, eigenfunctions, and seismological diagnostics. We find that increasing the propagation obliquity reduces the phase speed owing to both projection effects and the intrinsic dependence of the phase speed on the propagation angle. The wave structure also undergoes a gradual transition from a body mode to a surface mode, leading to stronger perturbations at the slab boundaries and enhanced wave localization. Consequently, for a given energy deposited by a CME impact, oblique kink waves are expected to produce larger observable amplitudes than field-aligned waves. Applying the developed theory to streamer waves reported previously, we infer Alfvén speeds in the range of 50-500 km/s. We show that neglecting wave propagation obliquity may underestimate the Alfvén speed by up to a factor of 1.5. These results demonstrate that wave propagation obliquity should be taken into account in coronal seismology of streamer waves and that stereoscopic observations will be required to constrain the true propagation direction.
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All authors Aleksandr V. Rubtsov, Valery M. Nakariakov, Dmitri Yu. Klimushkin, Ding Yuan
Plasma Physics
Horizon-Aware Early Event Prediction for Tokamak Disruption Alarms
Takeshi Koshizuka and Takaharu Yaguchi
Disruption predictors must warn the
plasma control system early enough for the intended response, and the required warning time differs between mitigation and avoidance. We view a warning system as a predictor that outputs a disruption risk and an alarm policy that acts on it, and ask which risk the predictor should learn. Binary classifiers do not specify when a disruption occurs, and survival analysis models the full distribution of the time to disruption, whereas an alarm depends only on the risk within a finite horizon. We introduce two horizon-focused targets into tokamak disruption prediction: a horizon-truncated survival objective and fixed-horizon early event prediction (EEP) with temporal label smoothing (TLS). We compare them with binary classification and survival analysis on the DIII-D, Alcator C-Mod, and EAST databases of DisruptionBench, evaluating the risk by its threshold-free ranking at a 40 ms deadline and the alarm policy by thresholds calibrated on validation data. On every device, TLS outperforms the deep survival models in both ranking and alarm performance; TLS performs best on DIII-D and EAST, and a random forest trained on a hard horizon target performs best on C-Mod. TLS also improves the calibrated alarm performance over hard targets placed at either end of its smoothing range on all devices, isolating the benefit of label smoothing. Horizon truncation alone did not consistently improve survival analysis. Alarm performance remains limited on C-Mod and DIII-D and varies strongly across training seeds, and ablations show that the target should extend to the required warning time.
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Optics · Cross-listed from quant-ph
Versatile Quantum Machine Learning with an Ultra-low Power Photonic Quantum Reservoir Computer
Wei Wang, Zan Tang, Menglong Fang et al. (+7 more)
Integrated photonic microprocessors provide high-bandwidth, massively parallel linear computation, but realizing nonlinear feature maps and temporal
memory remain key challenges for machine learning. Conventional approaches rely on active tuning and additional nonlinear elements, increasing architectural complexity and power overhead. Here we demonstrate an integrated photonic
quantum reservoir computer that achieves nonlinear mapping, fading
memory, and task versatility without active tuning of the reservoir core. The same chip supports accurate static classification, dynamic prediction, and stable autonomous forecasting, establishing broad utility across both classification and temporal inference tasks. Competitive performance is retained in the zero-bias state, where all on-chip phase shifters are unpowered, eliminating active control and reducing computational power consumption to zero. This passive operation highlights a scalable route to multifunctional machine-learning hardware, where large-scale photonic
quantum processors can be repurposed as reservoirs without reconfiguring their internal optical networks. By combining
quantum-state encoding, multimode interferometric mixing, and
photon-statistical readout, this architecture provides a physically grounded paradigm for low-power, large-scale
quantum reservoir computing.
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All authors Wei Wang, Zan Tang, Menglong Fang, Daiqin Su, Mile Gu, Jayne Thompson, Lip Ket Chin, Hong Cai, Leong-Chuan Kwek, Ai-Qun Liu
Fluid Dynamics
Edge Contact Lubrication
Andrew Wilkinson, Michael A. Morgan and Michael Wilkinson
In this paper we discuss the dynamics of a lubricating film separating two flat surfaces. It may be possible for the gap between the surfaces to reduce to zero at one point on the boundary in a finite time. Typically, the maximum pressure diverges as the gap between the surfaces approaches zero. We discuss the form of the pressure field in the vicinity of its maximum. We also introduce a numerical method for accurate determination of the pressure across the lubrication surface, enabling us to determine the hydrodynamic forces. We determine the phase diagram describing the
evolution of the gap, as a function of the initial configuration and of the line of action of the external forces. When contact does occur, we consider whether the subsequent motion involves sliding of the point of contact. We argue that, when sliding does occur, the motion does not depend upon the microscopic properties of the surface roughness.
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Computational Physics
VNS Tokamak for Medical Isotope Production
Christopher Ehrich, Pavel Pereslavtsev, Christian Bachmann et al. (+1 more)
The Volumetric
Neutron Source (VNS) tokamak is a proposed fusion reactor for testing components under fusion
neutron irradiation, and has potential use for radioisotope production. The VNS geometry is modeled in the Serpent 2.2.2 and OpenMC 0.15.2 neutronics codes. Coupled
neutron-
photon simulations compared fluxes, spectra, and selected reaction rates in the blanket and
vacuum vessel. Good agreement was found overall, with the largest difference found in (n, 2n) reactions. On an HPC cluster, Serpent 2 was found to have shorter computation time in coupled simulations, while OpenMC was faster in
neutron only simulations. Radioisotope production yields were simulated in Serpent 2.2.2 for capsule and Cobalt plate irradiation facilities. Results indicate potential for large volume production of 99Mo, 131I, 225Ac, 177Lu, 192Ir, 64Cu, 67Cu, 161Tb, and 153Sm while 203Pb indicates lower potential. 100Mo and LEU target heating was calculated, suggesting the LEU target mass or the cooling may need adjustment. Optimized 60Co production yielded 1.2 GBq/mg and 100,000 TBq after a 3-year irradiation period. Sensitivity to plant outage for 99Mo, 131I, 177Lu, and 60Co was simulated, suggesting irradiation can be restarted for the same isotope loading and demonstrated long-lived 60Co to be robust to long plant dwell-time.
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All authors Christopher Ehrich, Pavel Pereslavtsev, Christian Bachmann, Christian Reiter
Fluid Dynamics
A closed-form solution for streaming and Lagrangian transport in a deforming circular cavity
Zijian Liu, Julian Olszewski, Yang Lin et al. (+3 more)
Streaming from a deforming cavity wall serves micromixing, pumping and particle handling. We solve it in closed form in a two-dimensional circular cavity, for any azimuthal wall mode $m$, as $\mathrm{Wo}^2 \to 0$. A biharmonic inversion against the Reynolds stress, corrected by the second-order slip a moving wall imposes, gives the Lagrangian mean a tracer follows for a deforming no-slip wall, $\psi_L = -[m(5m+4)a_m^2/(128(m+2)(2m+1))]\,r^{2m}(r^2-1)^2\sin 2m\theta$, with a companion form for a shear-free interface. For a single mode the factor $(5m+4)/(m+2)$ relating it to the auxiliary solution $\psi_2$ is the same for every member of the co-phased prescribed-velocity family; at $m=2$ the physical Eulerian mean peaks an order of magnitude above $\psi_2$, with opposite sign. The no-slip
cell centers lie at $r^2 = m/(m+2)$, and at large $m$ the peak streamfunction falls as $m^{-2}$, the peak speed as $m^{-1}$. At fixed radial wall-velocity amplitude the ranking over $m$ follows the wall kinematics: an externally driven wall peaks at $m=1$, a wall with zero first-order surface strain at $m=3$. Mode superpositions invert without degenerating, each harmonic carrying its own correction. At finite $\mathrm{Wo}$ the first-order field stays closed form in Bessel functions and the mean flow reduces to quadrature; the construction approaches the $m=2$ Rayleigh limit on a separate tangentially driven boundary problem. An independent finite-element solver, with the closed form withheld, reproduces $\psi_2$ with quadratic mesh convergence.
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All authors Zijian Liu, Julian Olszewski, Yang Lin, Yuan Gao, Mengren Wu, Jie Xu
Fluid Dynamics
Bubble detachment from circular cavities and flat surfaces
Ianto Cannon, Stefan Endres, Lutz Mädler et al. (+1 more)
We determine the maximum stable volume of bubbles attached to flat surfaces as a function of contact radius, contact angle, and capillary length. By solving the Young-Laplace equation using a shooting method, we calculate
equilibrium bubble shapes and determine when bubbles detach through three distinct modes: necking at the cavity, sideways instability, and spreading followed by necking on the surrounding surface. Our predicted detachment volumes agree well with experimental measurements of electrolytic, boiling, and carbonated bubbles, as well as pendant drops. These results bring together and extend previous analytical estimates and, by
symmetry, also apply directly to pendant drops.
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All authors Ianto Cannon, Stefan Endres, Lutz Mädler, Marc Avila
Computational Physics · Cross-listed from hep-ph
Multitask Jet Analysis with Vision-Language Models: A Physics-Informed Four-Panel Representation
Lu Zhang, Rachik Soualah and Abbes Amira
The enormous recorded data at high-energy physics (HEP)
colliders make the accurate identification of physics objects a bottleneck in disentangling event
topologies, where machine learning has become a standard tool for jet tagging. In this work, we examine whether
Vision-
Language Models (VLMs) can provide a common interface for structured jet analysis from a single physics-informed image. Each JetClass jet becomes a 224x224 RGB image with four panels encoding p_T flow of all constituents; charged-
hadron, neutral-
hadron, and electromagnetic composition; p_T-weighted impact-parameter significances with displaced-track multiplicity; and signed-track p_T densities with local p_T^k-weighted jet-charge asymmetry. Four open VLMs are adapted with low-rank adaptation (LoRA) for class classification across QCD,
Higgs, W/Z, and top jets, six-field attribute prediction, and cross-panel consistency with replaced-panel localization, evaluated on 24000 balanced JetClass test jets. Ablations identify the impact-parameter lifetime signature of heavy-flavor tagging as dominant, with jet charge separating the nearly mass-degenerate hadronic W and Z. Zero-shot recall stays near chance (3.33%-10.57%), once adapted, Task 1 Macro recall grows monotonically with training size, and Gemma4-E4B reaches 75.05% (74.87% F_1), 93.31% Task 2 field-mean, and 99.88%/99.75% binary/localization recall. Reallocating budget toward W/Z jets raises Zqq recall by up to 9.83 points at near-constant Macro recall. Transfer to broader-
topology JetClass-II and real-data Aspen Open Jets (probing the simulation-to-data gap) is retained: with 3000 target jets, Task 1 recall exceeds 70% on JetClass-II and every Task 2/3 metric exceeds 92%. Thus rasterizing energy flow, species, displacement, and jet charge, with parameter-efficient adaptation, supports jet analysis through one instruction-conditioned interface for future
collider data.
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Fluid Dynamics · Cross-listed from math.NA
Autoencoders vs. Numerical Analysis–Informed Manifold Learning for Navier–Stokes Flows
Alessandro Della Pia, Lucia Russo, Ioannis Kevrekidis et al. (+1 more)
Autoencoders (AEs) have become a dominant approach to nonlinear latent-space construction in data-driven reduced-order modelling (ROM), with their decoders lifting latent representations back to the ambient state space. Their prominence, however, has overshadowed an established alternative:
manifold-learning methods grounded in classical numerical analysis. We revisit this alternative using Parsimonious
Diffusion Maps (PDMs), benchmarking them against Proper Orthogonal Decomposition (POD)-based ROMs and several convolutional AE architectures for the two-dimensional incompressible flow past a rotating cylinder —a bifurcating Navier-Stokes (NS) system organized by a codimension-2 Bogdanov-Takens point and its associated Hopf, saddle-node, and homoclinic bifurcations. Our approach uses PDMs to identify a parsimonious and interpretable set of intrinsic latent coordinates and to estimate their dimension directly from data. Gaussian process regression then learns the latent dynamics, while convex K-nearest-neighbor (K-NN) interpolation in PDMs space constructs the pre-image map, for which we establish pointwise consistency. The resulting nonlinear ROM substantially outperforms POD-based ROMs and achieves reconstruction and prediction accuracy comparable to —and, in some bifurcating regimes, better than— that of AE-based ROMs. At the same time, latent-variable learning with PDMs requires orders of magnitude less computational time than AE training.
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All authors Alessandro Della Pia, Lucia Russo, Ioannis Kevrekidis, Constantinos Siettos
Fluid Dynamics
Impact of a resonator on vortex induced vibrations of a wind turbine airfoil
Sergio Horcas, David Roca, Enrique Ortega et al. (+1 more)
The aeroelastic instability known as
vortex induced vibrations (VIV) has its origin in the coupling of bluff body shedding and the structure dynamics, and can have adverse effects on several industrial fields. In this work the use of locally resonant metamaterials (LRM) is explored as a wind turbine blade VIV mitigation strategy. The problem is cast into a classical airfoil in transverse oscillation, elastically mounted. A fluid structure interaction model is then generated and validated for the main system. This is achieved using an open source finite volume code with arbitrary Lagrangian Eulerian capabilities and a built-in rigid body motion solver. Subsequently, the capabilities of the code are extended by coupling the dynamics of a single resonator into the main system through a tailored development. The performance of the resonator was evaluated for different designs, which were parameterized mainly by the resonator frequency and its relative mass with respect to the airfoil. Analysis of the results identified a frequency band where the resonator effectively influenced vibration amplitudes. However, the amplitude attenuation was very low when considering realistic relative resonator masses. In particular, achieving a 50% amplitude reduction required a mass ratio larger than 0.25. Studying the mechanisms uncovered the cause of these beneficial effects, which relied on the aeroelastic frequency bifurcation introduced by the resonator. These fundamental findings open the door to future applications of alternative technologies for VIV suppression.
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All authors Sergio Horcas, David Roca, Enrique Ortega, Juan Cante
Optics
Non-Hermitian photonic time quasicrystal
Shuhang Chen, Zhi Zheng and Qi Zhu
Photonic time
crystals amplify waves through temporal modulation. We study a temporal analogue of the non-Hermitian Aubry-André-Harper model. By continuing an incommensurate temporal modulation into the complex phase plane, we find that the bulk amplification rate as a function of the complexification coordinate is organized into distinct integer phases, with its slope locked to an integer within each phase. This integer is Avila's acceleration, connecting a global structure of quasiperiodic operator theory with a directly observable optical propagation response. The quantized response persists in the presence of defects in the time-dependent permittivity modulation that preserve the underlying analytic phase structure. As a wave-level consequence, two input frequencies belonging to different integer phases acquire exponentially separated amplification, producing spectral selection and reshaping the temporal beat pattern. Our results establish that a global integer of quasiperiodic operator theory can govern a tunable, quantized growth response in a non-Hermitian photonic time quasicrystal.
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Optics · Cross-listed from cond-mat.mtrl-sci
Amorphous insulating MoS$_x$ films deposited by magnetron sputtering as a low-index optical coating
S.G. Martanov, E.V. Tarkaeva, A.V. Muratov et al. (+4 more)
While much effort are now concentrated on exploration of crystalline form of MoS$_2$ as a two-dimensional material, we show that room-temperature DC magnetron sputtering from pressurized MoS$_2$ powder target produces amorphous MoS$_x$ films with optical properties fundamentally different from those of crystalline MoS$_2$. The films were found to have a sulfur content of approximately $x=1.8$, indicating sulfur deficiency. They are optically isotropic and exhibit rather low optical losses, with a refractive index of about 2 over the visible and near-infrared spectral range. Their compatibility with lift-off lithography and dry etching makes amorphous MoS$_x$ a promising material for integrated photonic applications.
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All authors S.G. Martanov, E.V. Tarkaeva, A.V. Muratov, A.V. Lubenchenko, O.N. Pavlov, A.G. Vitukhnovsky, A.Yu. Kuntsevich
Instrumentation and Detectors · Cross-listed from hep-ex
Jevons' Paradox and Fast Generative Simulation for HEP: Why Realistic Benchmarking is Essential
Thorsten Buss, Henry Day-Hall, Frank Gaede et al. (+7 more)
Simulation is a major computational expense in HEP, and calorimeter simulation in particular drives the overall energy cost of our physics analyses. Future detectors will contain more finely grained calorimeters than ever, and their data analyses will demand unprecedented simulated statistics. Fast generative models redefine what is possible, producing simulations 100 times more efficiently. This article addresses Jevons' paradox in our field and considers the importance of realistic metrics in achieving "true" efficiency.
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All authors Thorsten Buss, Henry Day-Hall, Frank Gaede, Gregor Kasieczka, Katja Krüger, Anatolii Korol, Thomas Madlener, Peter McKeown, Martina Mozzanica, Lorenzo Valente
Computational Physics · Cross-listed from astro-ph.IM
Scale-Vector Alignment: A Scale-Aware Framework for Spatially Resolved Morphological Similarity in Astronomical Images
Mengke Zhao, Guang-Xing Li, Keping Qiu et al. (+1 more)
Astronomical maps made with different tracers are not expected to have identical morphology. Excitation, optical depth, chemistry, radiation, and ISM phase alter the response of a tracer, and the resulting differences can depend on both position and spatial scale. We propose scale-vector
alignment, a scale-aware method based on Constrained
Diffusion Decomposition (CDD). CDD decomposes an image into localized scale components; at each position, their amplitudes define a scale vector that describes how the measured intensity is distributed over spatial scale. We define the pixel-wise similarity $\Spix(x,y)$ as the normalized
alignment of two local scale vectors. The normalization removes the overall amplitude, so $\Spix$ compares relative scale composition rather than absolute flux. We also define the scale-wise similarity $\Sscale(l)$ by comparing the two CDD component maps at each spatial scale. Spatial shifts are used to construct an empirical shifted reference distribution for $\Spix$. In Orion~A, the tracer with the highest similarity to the dust-derived column-density map changes from $^{12}$CO to $^{13}$CO to C$^{18}$O toward higher column density. In NGC~6334I(N), the line–continuum similarity decreases locally around the brightest compact structures, where radiative-transfer effects can alter the observed line morphology. In NGC~3627, CO is most similar to 21~$\mu$m emission, and $\Sscale$ reaches its maximum at an intermediate sub-kpc scale. The method measures where two tracers have similar multiscale structure and at which scales their spatial distributions agree. The implementation is publicly available at https://github.com/meng-ke/Scale-Vector-
Alignment.
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All authors Mengke Zhao, Guang-Xing Li, Keping Qiu, Shanghuo Li
Atmospheric and Oceanic Physics · Cross-listed from cs.DC
Toward GPU-Resident Climate Models: A Feasibility Study on Lossy Compression for the Spherical Harmonic Transform's Communication Bottleneck
Lorenzo Breschi and Flavio Vella
Operational pseudospectral atmospheric models such as the ECMWF Integrated Forecasting System (IFS) run today almost exclusively on CPUs; GPU ports are under active development but not yet used in production. These models rely on the Spherical Harmonic Transform (SHT). Each time-step requires forward and inverse SHTs, and both passes depend on global pencil transposition that redistribute multi-dimensional arrays across compute nodes. At large node counts these global collectives dominate wall-clock time. We investigate GPU-resident lossy compression, using representative fields from the DYAMOND high-resolution operational
dataset as input, and combining measured GPU compression throughput with SimGrid network simulation, we show that ZFP at 16 bits per value (rate-16), about the same storage budget as float16, matches the communication-time reduction of float16 truncation while delivering approximately $\mathbf{1600\times}$ lower mean relative error. ZFP at 8 bits per value (rate-8) achieves approximately $\mathbf{1.93\times}$ the speedup of float16 while retaining $\mathbf{4\times}$ lower mean relative error.
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Fluid Dynamics
Quantum many-body framework for passive-scalar turbulence
Zhaoyuan Meng, Long Wang and Guowei He
How spatial structures manifest in multi-time correlations is a fundamental question in
turbulence. We develop a non-Hermitian bosonic framework that unifies equal-time anomalous statistics and their temporal propagation within a common operator representation. A continuous Wegner flow reorganizes
stochastic mode couplings in an extended wave-frequency space. Applied to the Taylor-Kraichnan model, the framework recovers the established equal-time hierarchy and constructs multi-time contributions through propagators acting on successively smaller sets of active fields. This construction separates uniform transport from intrinsic relative dynamics and shows how a higher-order equal-time state evolves under a generator acting only on the fields that remain dynamically active. Within an isotropic radial closure, we derive an explicit fourth-order two-time zero mode scaling function that describe how relative dispersion progressively weakens sensitivity to the initial separation. The framework thus connects spatial intermittency to temporal
evolution by identifying how the sequence of observation times determines the propagation of equal-time anomalous structures.
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