Materials Science
Selective faceting induced by Hexagonal Boron Nitride on curved Platinum substrate
Alaa Mohammed Idris Bakhit, Muhammad Saad Mahmood, Khadiza Ali et al. (+5 more)
This work combines experimental investigations and first-principles calculations to study hexagonal boron nitride (hBN) growth on a curved Pt(331) substrate. Low-energy electron diffraction (LEED) and scanning tunnelling microscopy (STM) were employed to investigate the structural properties, observing that hBN growth led to faceting with several stable facets: Pt(111), Pt(221), Pt(441), Pt(881), and Pt(110). Additionally, the electronic properties were examined by X-ray photoemission spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS), revealing an increase in the hBN-substrate interaction strength, from the weakest at the Pt(111) to the strongest at the Pt(110). Density functional theory (DFT) calculations confirm that the selective faceting mechanism is induced by hBN, which changes the order of relative stability of the uncovered facets. Although a complete understanding of the process is not achievable using only thermodynamical arguments, the comparison between hBN adhesion energies and clean surface free energies clearly indicates that some facets are stabilized with respect to others by stronger overlayer-substrate interaction, whereas for others the clean surface energetics plays the dominant role.
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All authors Alaa Mohammed Idris Bakhit, Muhammad Saad Mahmood, Khadiza Ali, Anna A. Makarova, Igor Piš, Federica Bondino, Frederik Schiller, Maria Peressi
Accelerator Physics
Multi-Objective Design of C-Shaped Targets for Energy–Divergence Control in Laser-Driven Proton Acceleration
Mohammad Rezaei-Pandari, Mahdi Shayganmanesh and Mohammad Hossein Mahdieh
We optimize the energy-divergence trade-off of
laser-driven
protons from a C-shaped target using two-dimensional particle-in-
cell simulations and constrained multi-objective
Bayesian optimization. Five geometry and focusing parameters are varied to maximize
proton cutoff energy and minimize the RMS divergence of forward
protons with E_k >= 5 MeV under a
proton-only conversion-efficiency constraint of eta_H >= 9%. Of 82 designs, 60 are feasible and 15 Pareto-optimal. The Max-Energy and Min-Divergence endpoints yield 28.64 MeV at 52.51 degrees and 11.47 MeV at 11.13 degrees, respectively; a representative compromise yields 21.44 MeV at 38.44 degrees. Matched-stage diagnostics link these regimes to optical-field buildup, electron energization, charge separation, and outer-sheath organization. Numerical tests support the principal trends. Reflection timing does not support a monotonic trapping-duration law, and the charge-sheath relation remains non-local. These results establish a design-resolved route to controlling
proton energy and angular quality.
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Instrumentation and Methods for Astrophysics
Modelling the Point Spread Function of ILMT images
Naveen Dukiya, Bhavya Ailawadhi, Talat Akhunov et al. (+11 more)
We have devised an approach to model the empirical Point Spread Function (PSF) of the images taken with the 4-meter International
Liquid Mirror
Telescope (ILMT). The characteristics of the ILMT PSF are influenced by the nature of the
Liquid Mirror, as well as by instrument specific and atmospheric factors. As the
telescope uses Time Delay Integration (TDI) mode for tracking the passing objects, the PSF varies along the declination axis due to differential motion and
star-trail
curvature. The 5-element optical corrector homogenizes the PSF to some degree, but does not completely eliminate the disturbing effects mentioned above. The PSF in the RA direction is changing due to the sky conditions. We show that we can successfully model the PSF of 4k$\times$4k chunks using PSFEx, accounting for second-order X-Y variability. Our software robustly reproduces the PSF and its variation across the field.
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All authors Naveen Dukiya, Bhavya Ailawadhi, Talat Akhunov, Monalisa Dubey, Sara Filali, Paul Hickson, Priyanshi Kumari, Gokul Singh Mehra, Kuntal Misra, Vibhore Negi, Kumar Pranshu, Jean Surdej, Sarvesh Kumar Yadav, Archana Gupta
Geophysics
Depth-progressive 3D seismic velocity model building via 2D generative diffusion models
Shijun Cheng, Randy Harsuko, Mohammad H. Taufik et al. (+1 more)
Three-dimensional (3D) velocity model building (VMB) remains computationally challenging with conventional approaches and native 3D neural networks, largely due to the prohibitive
memory and training cost of full 3D formulations. Therefore, we introduce a depth-progressive framework that achieves 3D VMB using 2D generative
diffusion models through a depth-as-channel formulation, in which the depth dimension of each 3D velocity patch is mapped to the channel dimension of a 2D U-Net. This allows the model to synthesize overlapping depth patches sequentially from shallow to deep while conditioning the prediction of the deeper patch on the shallower one, as well as on any available geophysical constraints, including well logs and structural attributes. During training, paired shallow-deep patch pairs with randomized overlaps are used to teach the network how deeper velocity structures relate to shallower information, and a classifier-free guidance strategy enables the model to handle missing constraints gracefully. At inference, starting from a shallow velocity prior, the model recursively generates deeper patches in a top-down manner, and a depth-attenuated Gaussian blending scheme merges overlapping predictions into spatially coherent 3D volumes while accounting for the progressive accumulation of uncertainty at greater depths. Numerical experiments on both in-distribution
benchmark models, including Overthrust, SEAM Arid, and SEG/EAGE, and the out-of-distribution Marmousi model demonstrate that the method effectively propagates shallow velocity priors downward and produces high-quality 3D velocity volumes across a range of geological settings and conditioning scenarios. Compared to a 3D
benchmark of equivalent architecture, the proposed method significantly reduces parameter count, training cost, and inference cost, while maintaining superior VMB accuracy.
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All authors Shijun Cheng, Randy Harsuko, Mohammad H. Taufik, Tariq Alkhalifah
Mathematical Physics · Cross-listed from math.CA
On best approximation and estimates of Bohr–Favard type on the sphere for functions with bounded Laplacian
Alexey Solyanik
We determine the best constants in estimates of the $L^\infty$ norm of functions on the sphere with bounded
Laplacian whose first spherical harmonic components vanish. In every dimension $d\geq2$, these constants are expressed through weighted $L^1$ extremal
polynomials. On $S^2$ the constant is an explicit positive series, and the best coefficient of $n^{-2}$ is $7\zeta(3)/4$. On $S^3$ the best coefficient of $n^{-2}$ is a positive integral involving the Hörmander–Bernhardsson extremal function. In higher dimensions the rescaled extremal
polynomials converge to weighted entire extremals, which give asymptotic formulas for the Bohr constants on $S^4$ and $S^6$. The most unexpected and, in our view, interesting observation is that, for every fixed $n\geq2$ on $S^2$ and $S^3$, the constants in best approximation estimates are strictly smaller than the corresponding Bohr–Favard constants.
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Cosmology and Nongalactic Astrophysics
Gravitational waves from strong first-order phase transitions in an expanding Universe
Jintao Zou, Zizhuo Zhao, Yongtao Jia et al. (+1 more)
We investigate the gravitational waves generated by first-order phase transitions (PTs) in an expanding Universe. Using a scalar field-fluid coupled model, we perform three-dimensional
lattice numerical simulations of slow first-order PTs with strong strength. We observe that the contribution from sound waves to the gravitational wave (GW) signal significantly dominates over that from bubble collisions. The sound wave spectra exhibit two peaks located at the mean bubble separation and the sound-shell width. Rotational modes are generated in the fluid during the bubble collisions, and their magnitude grows with the PT strength. The lifetime of the sound wave source increases with decreasing $\alpha$: for weaker transitions the source can persist for longer than a Hubble time, while for stronger transitions it decays within a Hubble time. When the walls propagate as deflagrations, the GW spectral shape changes drastically, with steeper ultraviolet tails and a shorter-lived sound wave source. We also observe that the magnitude of the normalized GWs is roughly an order of magnitude smaller than obtained in the Minkowski spacetime simulations.
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All authors Jintao Zou, Zizhuo Zhao, Yongtao Jia, Ligong Bian
Soft Condensed Matter
Active remodeling rescues a microswimmer from geometric trapping
Ayushi Bhatt, Nico Schramma, Jasper van der Gucht et al. (+1 more)
Natural habitats confront microorganisms with heterogeneous, mechanically complex surroundings that shape how they move and explore. Most studies of motility in complex media treat the environment as either a homogeneous fluid or a rigid obstacle field. Here we instead study a medium that is simultaneously soft and reconfigurable — deformable by the organism moving through it. We track the unicellular biflagellate microalga Chlamydomonas reinhardtii swimming in a soft, disordered suspension of microgel particles comparable in size to the
cell itself, across a range of gel packing fractions. With increasing packing fraction, trajectories change from long straight runs to short, frequently reorienting ones, and the effective translational diffusivity decreases monotonically. The bimodal run/tumble speed distribution, characteristic of the free-swimming gait, collapses toward a single mode as the packing fraction increases, by near-proportional slowing of both gait states rather than a redistribution of
cells between them. Recasting trajectories as alternating hops and traps reveals the signature of a deformable medium: hop lengths halve as the gel densifies, approaching the microgel aggregate scale, while trapping times do not increase with increasing packing fraction. Independent force estimates place the
cell's propulsive force close to an order of magnitude above that needed to deform a single grain, so remodeling is expected rather than merely observed. A minimal active remodeler model — an active Brownian particle among mobile, rigid obstacles — shows that obstacle mobility alone is sufficient to relocate the onset of permanent trapping. Thus, our results establish obstacle mobility as a control parameter for motility in soft, disordered matter.
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All authors Ayushi Bhatt, Nico Schramma, Jasper van der Gucht, Uddalok Sen
Instrumentation and Methods for Astrophysics
Mid-IR Water-Vapor Seeing: Implications for ELT/METIS High-Contrast Imaging from VLTI Data
Abhirami S Raghu, Prashant Pathak, Olivier Absil et al. (+7 more)
Direct imaging and characterization of rocky
exoplanets remains one of the central challenges in exoplanetary science. The mid-infrared (mid-IR) offers a favorable high-contrast imaging (HCI) regime, as the
planet-
star contrast is more moderate than at shorter wavelengths. However, mid-IR observations with extremely large ground-based
telescopes (ELTs) are strongly affected by spatio-temporal fluctuations in atmospheric water vapor (WV), which introduce chromatic wavefront errors that are largely invisible to adaptive optics systems operating at shorter wavelengths. This poses a significant challenge for mid-IR HCI instruments such as METIS, which aims to detect thermal emission from rocky
exoplanets in the $N$-band (8–13 $\mu$ m). To quantify WV-induced wavefront errors, we analyze $K$-band fringe-tracker data from the
GRAVITY instrument at the VLTI and derive the optical path difference between group-delay and phase-delay measurements. This difference provides a direct measure of the differential WV column density ($\Sigma$) above the
telescopes. We examine the dependence of the RMS differential WV column density ($\sigma_{\Sigma}$) on precipitable water vapor (PWV), airmass, seeing, and wind speed across multiple VLTI configurations. Among these parameters, PWV shows the strongest correlation with $\sigma_{\Sigma}$. We further explore the influence of the vertical PWV distribution on this relationship. Next, we use power-spectral-density analysis to quantify how increasing PWV modulates $\Sigma$ variability. The wavefront error associated with this phenomenon on ELT scale is approximately 15~nm RMS in the $L$-band and 175~nm RMS in the $N$-band, relative to the $K$-band. These results provide a quantitative framework for assessing and mitigating atmospheric WV effects in next-generation mid-IR HCI instruments.
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All authors Abhirami S Raghu, Prashant Pathak, Olivier Absil, Benjamin Courtney-Barrer, Gilles Orban de Xivry, Julien Woillez, Alexis Matter, Philippe Bério, Roy van Boekel, Bernhard Brandl
Atomic Physics
Inverse identification of thermal-radiative parameters for reduced effective-temperature uncertainty in an ion optical clock
Jie Zhao, Yani Zuo, Shaoyang Dai et al. (+8 more)
The blackbody-radiation (BBR) shift remains a leading systematic uncertainty of room-temperature single-ion optical clocks. Accurate evaluation of this shift requires the effective temperature at the ion position, which is difficult because RF heating, low and spatially varying surface emissivity and inaccessible trap surfaces make this quantity difficult to measure directly. Here, we developed a hybrid inversion framework that combines radiance-domain infrared thermography, black-painted high-emissivity reference regions, a finite-element model of a 171Yb+ end-cap ion trap and a reduced-order surrogate for repeated forward calculations and parameter identification. The surrogate reproduced the FE test fields with a full-field mean absolute error (MAE) of 0.02220 mK. The calibrated model predicted the ion-position effective temperature with a combined standard uncertainty of 155.0 mK, corresponding to a temperature-related BBR frequency-shift uncertainty of 1.647 x 10^-19 for the 2S1/2-2F7/2 (467 nm) E3 transition. This method provides a reproducible route for reducing and tracing the BBR uncertainty of room-temperature trapped-ion optical clocks.
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All authors Jie Zhao, Yani Zuo, Shaoyang Dai, Chaowei Wang, Ang Huang, Jian Song, Guangyao Wang, Fangfei Wu, Haotian Shi, Zhengyong Li, Fang Fang
Earth and Planetary Astrophysics
Milani and Juventas Optical Navigation Images in Support of the Hera Radio Science Experiment
Edoardo Gramigna, Ozgur Karatekin, Birgit Ritter et al. (+7 more)
The European Space Agency's Hera mission aims to advance planetary defense by investigating the Didymos binary asteroid system following NASA's DART impact on Dimorphos. Incorporating simulated CubeSat images into Hera's orbit determination framework significantly improves positional accuracy, reducing uncertainties by up to three orders of magnitude for Milani and one for Juventas. This data enable more precise estimation of key parameters such as asteroid masses, rotational states, and moments of inertia, with up to 90% uncertainty reduction in Dimorphos' dynamical state under chaotic scenarios. Sensitivity analysis reveals the influence of pointing accuracy, image noise, and imaging frequency. Additionally, dedicated scientific investigations using Dimorphos-focused CubeSat images further advance understanding of the system. These findings underscore the critical role of CubeSat images in refining navigation and advancing science, offering valuable insights for future small-body missions.
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All authors Edoardo Gramigna, Ozgur Karatekin, Birgit Ritter, Iosto Fodde, Fabio Ferrari, Felice Piccolo, Paolo Tortora, Riccardo Lasagni Manghi, Marco Zannoni, Ryan S. Park
Quantum Physics
Entanglement generation from degeneracy breaking of superradiant Liouvillian steady states by local operations
Adam Burgess and Erik M. Gauger
Superradiance is a collective optical effect where emitters cooperatively radiate with a maximal intensity scaling proportional to the square of the number of emitters. Despite the superradiant cascade transitioning through highly entangled states, it has been shown that, for dynamics along the Dicke ladder, superradiance need not generate
entanglement between the emitters. By contrast, we show how introducing incoherent local processes – normally considered detrimental to both
entanglement and superradiance – can generate high levels of inter-emitter
entanglement. We develop a general framework, using degenerate non-Hermitian perturbation theory, for the study of superradiant Liouvillian steady-state degeneracy breaking by these local operations from a few emitters up into the thermodynamic limit. From this, we are able to show that
entanglement becomes ubiquitous in this regime and demonstrate its robustness against other forms of symmetric environmental noise. In the regime where pumping dominates, we find that population accumulates towards the maximally entangled minimal pseudo-
spin states, corresponding to multi-emitter singlet states. This provides a deeper insight into many-body
entanglement and the curious connection between local operations and
entanglement generation.
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Mathematical Physics · Cross-listed from math.AP
Global Well-Posedness and Uniform Long-Time Control for a Class of Periodic NLS-Dysthe Equations
Andrea Belloni and Filippo Giuliani
We study a class of periodic NLS-Dysthe (NLS-Dy) equations, also referred to as higher-order nonlinear Schrödinger equations (HNLS), of the form $i\partial_t u+a\partial_x^2u+b|u|^2u+i\varepsilon(c\partial_x^3u+d|u|^2\partial_xu+eu^2\partial_x\overline{u})=0$ with $ x\in\mathbb T$, $a,b,c,d,e\in\mathbb R$, $abc\neq0$, and $\varepsilon>0$. For $0<\varepsilon\ll1$, equations of this type arise as higher-order modulation models for some nonlinear dispersive PDEs, including the Klein-Gordon equation and the Serre-Green-Naghdi equation modeling the
evolution of nonlinear shallow water waves. We prove local well-posedness in $H^s(\mathbb T)$ for $s>3/2$ for arbitrary admissible coefficients, and establish an $H^1$ continuation criterion for $s\ge2$. In the parameter regime $e\neq0$, a lower-order conservation law provides uniform $H^1$ control and, together with the continuation criterion, yields global well-posedness for $s\ge2$. This result does not require the non-resonance condition appearing in Takaoka's periodic theory, while the condition $e\neq0$ naturally arises in the modulation setting considered here. Finally, motivated by the long-time regime relevant for modulation, we establish uniform long-time control without imposing a smallness assumption on the initial datum. Using the conservation laws of cubic NLS and their invariance under the commuting complex mKdV flow, we obtain uniform $H^s$ bounds on time intervals of order $\varepsilon^{-1}$ for integer $s\ge2$. For non-integer real $s\ge2$, the maximal $H^s$ solution exists on the same time scale, while uniform control is obtained at a lower regularity, with a loss of less than one derivative.
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Quantum Physics
Classical Communication Helps Single-Shot Quantum Compression
Omri Farber and Gilad Gour
Free classical communication can yield an unbounded single-shot saving in
quantum compression, even though it leaves the asymptotic rate of an i.i.d. source unchanged. At every fixed error in $(0,1)$, we exhibit sources whose unassisted compression cost is arbitrarily large, yet a single
qubit suffices with classical communication and no preshared
entanglement. We establish this separation by determining the exact optimal source fidelity for compression through an $m$-dimensional noiseless
quantum channel, with and without free classical communication, while preserving correlations with an inaccessible reference. Without classical assistance, the optimal fidelity is exactly the Ky Fan norm $\|\rho\|_{(m)}$, the sum of the $m$ largest
eigenvalues of the source state. With classical assistance, we obtain an explicit spectral threshold formula and a protocol attaining it. Classical communication strictly improves fidelity whenever $m$ is smaller than the source rank. The corresponding compression costs are two smoothed versions of the log-rank
entropy, also called max-
entropy: trace-distance smoothing under local operations and quadratic smoothing under LOCC. For i.i.d. copies of a fixed source with positive
entropy variance, however, the two costs have identical first-, second-, and third-order asymptotic terms. For nonlattice spectra, we determine the constant-order advantage: classical communication saves $\log_2(e)-1$ bits per block asymptotically, and the ratio of assisted to unassisted minimum communication dimensions converges to $2/e$.
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Earth and Planetary Astrophysics
Hera Orbit Determination Covariance Analysis of Didymos Binary Asteroid with the Full Two-Body Problem
Edoardo Gramigna, Riccardo Lasagni Manghi, Marco Zannoni et al. (+7 more)
Standard planetary
radio science analyses may be inadequate for accurately interpreting data from the Hera mission at the Didymos system due to the anticipated challenge posed by the coupling between the translational and rotational motions of the asteroids. A more precise dynamical model, the full two-body problem model, which includes a mutual gravitational potential, may be required to fit the Hera data properly. This work presents a covariance analysis of the Hera
radio science experiment using this advanced model. The tested dynamical scenarios are based on recent lightcurve observations indicating that Dimorphos is in an excited non-principal axis
spin state that is, on average, tidally locked. Three non-principal axis scenarios are analyzed using a multi-arc local estimation approach instead of the global one adopted in previous investigations involving non-chaotic states. The results show that tumbling or chaotic cases significantly improve the recovery of the bodies' moments of inertia due to the enhanced observability of the system's dynamics from the excited
spin state. However, the local estimation approach slightly degrades the accuracy of the mass estimation by a factor of 1.3-3 and Dimorphos' relative orbit by about one order of magnitude. Developing a dedicated constrained multi-arc filter is thus required to improve the estimation accuracy of the Didymos system's dynamical state further. Nevertheless, these results still meet the Hera
radio science requirements.
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All authors Edoardo Gramigna, Riccardo Lasagni Manghi, Marco Zannoni, Paolo Tortora, Michalis Gaitanas, Ioannis Gkolias, Kleomenis Tsiganis, Ryan S. Park, Alex Meyer, Petr Pravec
Cosmology and Nongalactic Astrophysics
TDCOSMO 2026: A 3% measurement of the Hubble constant from strong lensing and stellar kinematics
TDCOSMO Collaboration, Simon Birrer, Michele Cappellari et al. (+26 more)
We present cosmological constraints from 11 strongly lensed
quasars with measured time delays (hereafter, the TDCOSMO-2026 sample). In addition to expanding the sample, we improve many aspects of our blind analysis with respect to our 2025 analysis. Among other improvements, spatially resolved kinematics are available for nine systems, including six with JWST-NIRSpec, compared to one in 2025; for three lens models, JWST-NIRCam images now replace HST; axisymmetric dynamical modeling is applied directly to the spatially resolved data, instead of an axisymmetric correction factor applied to spherical models; and the line-of-sight convergence is now based on the Euclid Flagship simulations instead of the Millennium Simulation. Our baseline and primary result is based on the TDCOSMO-2026 sample, in combination with a prior on $\Omega_{\rm m}$ from the DES-Dovekie
supernova sample. In the flat $\Lambda$ cold dark matter ($\Lambda$CDM) cosmology, we find $H_0=71.1^{+2.4}_{-2.3}$ km.s$^{-1}$.Mpc$^{-1}$, a 3.3% uncertainty that accounts for the mass-sheet degeneracy. The SLACS and SL2S samples are in excellent agreement with the TDCOSMO-2026 sample, improving the precision on $H_0$ in flat $\Lambda$CDM to 3.0%. Using the DESI-DR2 baryon acoustic oscillations (BAO) likelihood instead of DES-Dovekie yields fully consistent results. We also present constraints in the open $\Lambda$CDM, $w$CDM, $w_0w_a$CDM, and $w_{\phi}$CDM cosmologies; the TDCOSMO $H_0$ inference is robust and consistent across all of them. The combination of the TDCOSMO+SLACS+SL2S likelihood with those from DESI-DR2 and DES-Dovekie disfavors $w=-1$ at the $2.3$-$2.5\sigma$ level in all three dark energy extensions that we tested. We find, e.g., $w_0=-0.88^{+0.04}_{-0.05}$ in $w_{\phi}$CDM and $w_0 = -0.85^{+0.07}_{-0.06}$ in $w_0w_a$CDM, while $w_a = -0.48^{+0.46}_{-0.44}$ remains consistent with zero.
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All authors TDCOSMO Collaboration, Simon Birrer, Michele Cappellari, Frédéric Courbin, Christopher D. Fassnacht, Pierre Fleury, Joshua A. Frieman, Aymeric Galan, Xiang-Yu Huang, Daniel P. Johnson, Sanjana Khanolkar, Shawn Knabel, Hrvoje Krizic, Martin Millon, Takahiro Morishita, Veronica Motta, Pritom Mozumdar, Eric Paic, Hadrien Paugnat, Allan G. Schweinfurth, Anowar J. Shajib, William Sheu, Dominique Sluse, Massimo Stiavelli, Sherry H. Suyu, Tommaso Treu, Felipe Urcelay, Devon M. Williams, Kenneth C. Wong
Quantum Physics
Avoiding Defects within Heavy-Hexagon Architecture
Hansol Kim and Younghun Kwon
When implementing scalable fault-tolerant
quantum computing using superconducting
quantum processors, one of the critical challenges to overcome is the presence of defective
qubits arising from fabrication and calibration imperfections. A defect on a specific
qubit severely restricts the connectivity between adjacent
qubits, disrupts stabilizer measurements, induces frequent detection events, and consequently inflates the logical error rate. To mitigate this issue, various strategies have been proposed, such as syndrome extraction
circuits based on stabilizer folding and the construction of super-stabilizers via gauge operators. However, these methods have primarily been developed for architectures with relatively high connectivity of 3 to 4. Furthermore, experimental demonstrations showing an actual reduction in logical error rates in the presence of physical hardware defects have been lacking. In this work, we propose a defect-avoidance scheme tailored for the heavy-hexagon architecture, which features a lower connectivity of 2 to 3. While previous approaches required four measurement cycles to measure all gauge operators comprising a super-stabilizer, our proposed scheme completes all gauge measurements within only two cycles. We experimentally validate this approach on IBM
quantum hardware by identifying physical defects and implementing the defect-avoidance
circuits. As a result, avoiding the defect yields an approximately 10% reduction in the logical error rate per cycle for both logical $X$ and $Z$ errors. These findings demonstrate that defects in superconducting hardware can be successfully handled even under the constrained connectivity of heavy-hexagon
lattices, and that defect avoidance substantially reduces logical errors on real
quantum hardware.
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Superconductivity
Driven Vortex Motion in Periodic Channel Potential Embedded in Superconducting Films
A. Al Luhaibi, A. Glatz, Michael Vogl et al. (+2 more)
In this paper, we investigate
vortex dynamics in periodically width-modulated superconducting channels by numerically solving the time-dependent Ginzburg-Landau (TDGL) equations. The channels are designed with sinusoidally varying widths characterized by their average width and modulation amplitude. The motion of driven
vortices generates an oscillatory electric field with a fundamental frequency, $f_0$, set by the channel periodicity, together with higher-order harmonics. In contrast to the situation of
vortex lattice dynamics in a periodic pinning landscape of circular holes considered by Al Luhaibi et al. [1], we show that the harmonic content of the generated electric field can be effectively controlled through the channel geometry. In particular, appropriately engineered channel profiles strongly suppress higher-order harmonics, yielding an electric-field response that closely approaches a pure sinusoidal waveform. These results demonstrate that
geometric modulation offers a viable route to engineering low-harmonicity microwave signals in superconducting devices and may enable cryogenic on-chip waveform generators for controlling superconducting
qubits. Such devices could provide a useful building block for scalable transmon-based
quantum computing architectures.
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All authors A. Al Luhaibi, A. Glatz, Michael Vogl, Hocine Bahlouli, J. B. Ketterson
Materials Science
Inverse Designing Reconfigurable Piezoelectric Tensors via Architectural and Modal Programming
Anish Satpati, Marco Maurizi, Hyunmoon Cho et al. (+3 more)
Piezoelectricity arises from the coupling between electric polarization and mechanical deformation, described by a third-rank tensor whose coefficients are constrained by
crystal symmetry. In natural
crystals, atomic periodicity and energetic stability restrict accessible
symmetries, limited to 20 distinct anisotropies that can exist. Here we establish a general framework, based on graph representation, for controlling the full effective piezoelectric tensor through architecture by resolving how macroscopic
symmetry, local polarization and deformation of structural elements act together. This enables each coefficient to be traced to the members that reinforce or cancel it and be controlled through targeted
geometric changes. We further uncover frequency-selective tensor reconfiguration, in which excitation frequency switches the dominant piezoelectric coefficients of a single architecture. These principles open a broader class of applications in which a single piezoelectric architecture can deliver programmable sensing, actuation and mode conversion across multiple directions and deformation states. We realize a multi-degree-of-freedom actuator that integrates distinct actuation modes in one block and reduces volume by 90% relative to conventional multi-stack assemblies.
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All authors Anish Satpati, Marco Maurizi, Hyunmoon Cho, Victor Couedel, Nicolas Mule, Xiaoyu Zheng
Quantum Physics
Clifford Invariants and Three-Copy Quantum Tests
Xingya Fan and Yongzhi Luan
We give an explicit treatment of the third tensor power of the Clifford representation on $n$ qutrits, for $n\geq2$. This representation has five pairwise inequivalent irreducible constituents, with multiplicities $1,1,1,1,2$. The decomposition reduces the Clifford twirl of a tensor cube to four real parameters. Two of them are spectral moments of the input. The other two are cubic invariants expressed as sums of cubes of the Weyl characteristic function and the discrete Wigner function. On trace-one Hermitian
matrices, the invariant
polynomials of degree at most three are spanned by the constant function and four algebraically independent functions. These functions do not separate Clifford orbits. For pure inputs a single parameter suffices. We recover its range and the characterization of its maximum by stabilizer states. We bound the stabilizer fidelity, determine full separability across the three copies in the symmetric family, and recover the criterion for a complex projective $3$-design. We classify the jointly invariant
quantum Boolean functions. For stabilizer testing and for testing unknown observables we give explicit bounds on copies and queries. We also give character formulas for the finite projective Clifford groups and record the complete character table for two qutrits.
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Chaotic Dynamics
Energy Transmission and Harmonic Propagation in Unidirectionally Coupled Plasma Oscillator Networks
K. Abirami, Miguel A. Prado-Reynoso and Miguel A.F. Sanjuán
We investigate signal transmission in a network of unidirectionally coupled
plasma oscillators, where only the first oscillator is driven by a weak periodic input. As the signal propagates through the network, nonlinear interactions generate higher-order harmonic components. Spectral analysis identifies five distinct transmission patterns for the fundamental frequency and odd harmonics, and four patterns for even harmonics, encompassing damped propagation, undamped transmission, and localized amplification. The transmission characteristics are governed by both the coupling strength and system parameters. Furthermore, we analyze how variations in these key parameters shape the overall signal dynamics.
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General Relativity and Quantum Cosmology
Stability conditions for light rings in circular stationary axisymmetric spacetimes
Jake O. Shipley
We consider the stability of light rings in four-dimensional circular stationary axisymmetric spacetimes. Using a
Hamiltonian formalism for null geodesics and the Killing
symmetries of the spacetime, we show that the transverse Hessian of the geodesic potential, which controls the light ring's stability, reduces there to a pure
curvature expression. Its
eigenvalues are $\mu_{\pm} = \Phi_{0 0} \pm \lvert \Psi_{0} \rvert$, where $\Phi_{0 0}$ is a Ricci scalar and $\Psi_{0}$ a Weyl scalar of a complex null tetrad adapted to the light ring. Through the Sachs optical equations, these quantities are responsible for focussing and shear of a null geodesic congruence. Stability requires both
eigenvalues to be positive, so a light ring is stable if and only if $\Phi_{0 0} > \lvert \Psi_{0} \rvert$ there. Assuming the Einstein field equations with generic stress–energy tensor $T_{a b}$, we recast this as $4 \pi T_{a b} p^{a} p^{b} > \lvert \Psi_{0} \rvert$, where $p^{a}$ is the light ring's tangent vector: for stability, the focussing by matter must dominate the local tidal shear. The trace of the Hessian alone provides an inexpensive test of stability, requiring no knowledge of the Weyl
curvature, since a light ring at which the strict null energy condition is violated cannot be stable. Applying the test to specific matter models, we recover known results for
vacuum and electrovacuum, with and without a cosmological constant. We also demonstrate that stable light rings are forbidden for a minimally coupled real scalar field with any self-interaction potential, since such a field must be invariant under both isometries. We show that a complex scalar field escapes this obstruction whenever it carries harmonic dependence on the Killing coordinates.
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Applied Physics
UV-cured PVA-collagen co-network with staining-free photodynamic activity against chronic wound bacteria
Nikitia Mexia, Charles Brooker and Giuseppe Tronci
Chronic wounds affect 1-2% of the global population and represent an unsustainable healthcare, financial and economic burden. Delayed healing is largely associated with bacterial infection and inadequate moisture balance, both of which remain difficult to control due to increasing antimicrobial resistance and the limited exudate management capacity and mechanical performance of current dressings. To address these challenges, we introduce a staining-free photodynamic material with work-light-triggered antibacterial activity, significant water-induced swelling (more than nine-fold increase in dry weight) and tunable wet state compression modulus (Ec: 76+/-34 - 289+/-94 kPa). The material was prepared by UV co-curing of an aqueous solution containing polyvinyl alcohol functionalised with both phenothiazine and methacrylate residues, 4-vinylbenzyl-functionalised type 1 rat tail collagen, and a water-soluble photoinitiator.
Fourier Transform Infrared spectroscopy and Differential Scanning Calorimetry of the co-networks indicated the presence of characteristic chemical and thermal features of both components. 96-hour co-network incubation in vitro (pH 7.4, 37 degC) confirmed the significant retention of toluidine blue (> 93 wt.%), suppressed medium colouration, and an average mass retention higher than 98 wt.%. Exposure of the UV-cured samples to 10-min work light resulted in at least 1 log10 reduction in Staphylococcus aureus and Pseudomonas aeruginosa viabilities, in contrast to dark-control conditions, while the metabolic activity of L929 fibroblasts remained above 90%. The antibacterial properties, staining-free photodynamic behaviour, water-induced swelling, and wet-state mechanical properties achieved via network integration with functionalised collagen, make this material appealing for chronic wound healing applications and for on-demand delivery of localised therapies.
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Superconductivity
Kink boundary-induced polarity revealed by nonreciprocal charge transport in FeTe0.7Se0.3 superconductor
Shengyao Li, Ya Deng, Han Yan et al. (+7 more)
Nonreciprocal charge transport, characterized by direction-dependent electrical response, provides a powerful probe of electronic structure and a platform for rectification. However, its realization is typically governed by intrinsic
crystal symmetry, restricting the range of suitable materials. Here, we demonstrate nonreciprocal charge transport in an otherwise centrosymmetric
superconductor, FeTe0.7Se0.3 (FTS), through kink boundary-induced strain engineering. The stress relaxation during growth generates a cusp-like kink-band boundary with asymmetric
curvature, producing a spatially nonuniform strain field and an effective in-plane polarity that breaks inversion
symmetry. Pronounced nonreciprocal transport is observed under out-of-plane
magnetic fields, with strong dependence on current and temperature across the superconducting transition, in contrast to the negligible response in flat nanosheets. Our results identify kink boundary-induced
symmetry breaking as a general route to engineer nonreciprocal charge transport in centrosymmetric systems.
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All authors Shengyao Li, Ya Deng, Han Yan, Dianyi Hu, Zherui Yang, Xueyan Wang, Ming Yue, Qiong Wu, Zheng Liu, X. Renshaw Wang
High Energy Physics (Phenomenology)
$\chi_{c0}$ production in $\bar{\Lambda}n$ scattering process
Quan-Yun Guo, Zhuo Yu and Dian-Yong Chen
In the present work, we investigate the production of $\chi_{c0}$ in the $\bar{\Lambda} n \rightarrow \chi_{c0} K^{0}_{S}$ process by utilizing an effective Lagrangian approach. Based on the $\chi_{c0} \rightarrow n K^{0}_{S} \bar{\Lambda}$ decay observed by the BESIII Collaboration, the coupling constants are determined by fitting the $M_{K^{0}_{S} \bar{\Lambda}}$ and $M_{n K^{0}_{S}}$ invariant mass spectra, where eight $N$ and $\Lambda$ state are considered. Moreover, the parameters $\beta$ is taken to be 1, 2, 3 as special cases to check the parameter dependence. Our results show that two clear structures can be observed in both $M_{K^{0}_{S} \bar{\Lambda}}$ and $M_{n K^{0}_{S}}$ invariant mass spectra, which should correspond to $N(1720)/N(1895)$ and $\Lambda(1600)/\Lambda(1890)$, respectively. In addition, the contributions from $N(938)$ and $\Lambda(1116)$ intermediate states are much smaller than those of the above-threshold resonances. With the fitted parameters for $\beta=1$, 2, 3, the cross sections for $\bar{\Lambda} n \rightarrow \chi_{c0} K^{0}_{S}$ are estimated to be 1.9 nb, 4.2 nb, and 8.0 nb at $\sqrt{s}=6$ GeV, respectively. Furthermore, our estimations indicate that the differential cross sections for $\bar{\Lambda} n \rightarrow \chi_{c0} K^{0}_{S}$ reach a maximum in the forward angle region.
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Chaotic Dynamics
Nonlinear Signal Transmission and Harmonic Generation in Plasma Oscillator Chain with Coupling Asymmetry
K. Abirami, Miguel A. Prado-Reynoso and Miguel A. F. Sanjuán
We investigate signal transmission in a one-dimensional chain of $n$ locally coupled
plasma oscillators with asymmetric bidirectional coupling $(\epsilon_1,\epsilon_2)$. Our results reveal a clear contrast between symmetric and asymmetric interactions: while symmetric coupling suppresses signal propagation, coupling asymmetry enables efficient nonlinear transmission across the network. In particular, sustained long range transmission is achieved when the forward coupling strength exceeds the backward coupling strength ($\epsilon_1 > \epsilon_2$), as demonstrated through a comprehensive phase diagram in the $(\epsilon_1,\epsilon_2)$ parameter space. Furthermore, under asymmetric diffusive coupling, signal transmission can persist even when the first few oscillators in the chain undergo oscillation death. A central finding of this study is the intrinsic generation of higher harmonics induced by nonlinear interactions, leading to a pronounced reversal of vibrational resonance. This nonlinear redistribution of energy facilitates selective amplification and robust propagation of specific frequency components.
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Chaotic Dynamics
Wake-induced dynamics of soft-impact oscillators: Analysis and electronic experimental validation
Rohit Chawla, Soumyajit Seth and Vikram Pakrashi
This article presents an electronic experimental validation of discontinuity-induced bifurcations, including period-adding cascades, in a wake-induced dynamical system subjected to soft impacts. A cylindrical structure immersed in a cross-flow undergoes
vortex-induced vibrations and interacts with a movable barrier during the upper and lower branches of the response. The structural motion is modelled as a harmonic oscillator, while the fluctuating lift is represented by a Van der Pol oscillator. The soft contact interaction between the structure and the movable barrier is modelled using a bilinear restoring force, resulting in a piecewise-smooth wake-oscillator system. A systematic numerical investigation reveals period-adding cascades of periodic orbits interspersed with chaotic responses as the barrier distance and fluid-flow velocity are varied. The results are experimentally validated using an inductorless electronic analogue of the piecewise-smooth wake model constructed from operational amplifiers and implemented on a printed-
circuit board to improve experimental robustness. The route to instability of the periodic and aperiodic responses is further characterized using Floquet multipliers and Lyapunov exponents. A zero-time transverse discontinuity mapping is implemented to account for the
evolution of perturbations in the local neighborhood of the discontinuity boundary during stability analysis. The combined numerical, experimental, and stability analyses demonstrate the role of soft impacts in generating complex nonlinear responses in the wake-induced system.
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Computational Physics · Cross-listed from math.NA
Stochastic Geometrically Exact Beams: Continuous-Time Geometric Principles and Variational Discretizations
Minghang Du, François Gay-Balmaz, Tianzhi Li et al. (+1 more)
Geometrically exact beams naturally arise in physical phenomena and engineering practice for modeling flexible structures, such as soft robotic manipulators and DNA structures. To the best of our knowledge, there appear to be no
geometric integrators for
stochastic geometrically exact beams in a variational formulation. In this paper, we introduce variational principles for the dynamics of
stochastic geometrically exact beams, in both continuous- and discrete-time settings. By introducing perturbations via
stochastic potentials and
stochastic kinematics, we derive the equations of motion from a variational viewpoint. The resulting
stochastic geometric integrators simultaneously discretize time and space in a parallel manner, which provides a distributed computational framework for solving the
stochastic dynamics of complex beam systems. In particular, the proposed integrators are shown to be a
stochastic extension of the well-known deterministic staggered leapfrog scheme for the wave equation, and also a
stochastic extension of Yee's scheme for spatially one-dimensional computational electromagnetism. Numerical results are shown to demonstrate the effectiveness of the proposed approaches.
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All authors Minghang Du, François Gay-Balmaz, Tianzhi Li, Donghua Shi
High Energy Physics (Phenomenology)
Mixed leptogenesis sources and low-energy neutrino portals
Yingnan Xu
A mixed leptogenesis source and its low-energy
neutrino portal depend on the same heavy-particle amplitudes. We determine how this common origin restricts matching cancellations and the scalar population produced during reheating. For two Majorana mass levels, each containing a degenerate pair, the inclusive lepton-number-violating invariant fixes an allowed norm domain for the mixed dimension-five coefficient at specified threshold strengths. An aligned flavour texture makes the conventional source vanish as a
matrix and gives equal coupling norms for the two massive
neutrinos. A continuous family preserves the
neutrino-mass fit while relating the source to unequal light coupling strengths. The matched couplings give
benchmark vacuum lifetimes of $1.62\times10^{12}\,\mathrm{s}$ and $2.80\times10^{11}\,\mathrm{s}$, while reheating normalized to the baryon abundance determines the primary spectrum. In the massless Born approximation with dilute outgoing states, bath-produced scalars carry $4.81\times10^{-5}$ of the primary scalar energy but contribute $11.1$ times its variance. The positive production functional converts the matching constraint into a conditional variance bound. We derive the scalar-mass dependence of stimulated emission and the Hartree moment equation, keeping the scalar mass and quartic as renormalized matching inputs. These results link the leptogenesis source to light-
neutrino decay and the finite-density quantities entering subsequent coupled transport.
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Materials Science
Finite-temperature adiabatic-connection reduced density-matrix functional theory: a unified framework for i-DMFT and TAO-DFT
Jingang Han, Huanjing Gong, Kai Luo et al. (+2 more)
Accurately describing chemical bond breaking requires capturing strong/static electron correlation, a major challenge for single-reference self-consistent-field methods such as Hartree–Fock and Kohn–Sham density-functional theory (DFT). Fractional occupations substantially improve this situation, as demonstrated by information-density-
matrix-functional theory (i-DMFT) and thermally-assisted-occupation DFT (TAO-DFT). Although useful, they are formulated within rather different theoretical frameworks, are somewhat semi-empirical, and their relationship remains unclear. Here we introduce finite-temperature adiabatic-connection reduced density-
matrix functional theory (FT-AC-RDMFT), in which i-DMFT and TAO-DFT emerge as different reductions of a unified framework. The effective
eigenvalue equation for natural orbitals and the Fermi–Dirac occupation numbers follow directly from the variational principle, while a thermal adiabatic connection relates the empirical
entropy coefficient of i-DMFT to a characteristic temperature of the auxiliary non-interacting system. Within this framework, i-DMFT is the exact-exchange-based reduction, whereas TAO-DFT results when exact exchange is replaced by a density-based exchange-correlation functional. Numerical calculations confirm that i-DMFT, apart from a constant, coincides with the exact-exchange realization of the framework, and show that the improved dissociation behavior from finite-temperature occupations extends beyond exact exchange to hybrid and semilocal density functionals. For strongly correlated V2O3, finite-temperature occupations substantially reduce the severely overestimated non-
magnetic LDA bulk modulus, bringing it close to experiment. These results establish FT-AC-RDMFT as a common theoretical foundation for finite-temperature occupation-based electronic-structure methods in molecular and solid-state systems.
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All authors Jingang Han, Huanjing Gong, Kai Luo, Hongming Weng, Xinguo Ren
Optics
Selective spatiotemporal mode-locking in multimode Mamyshev oscillators
Changfeng Wang, Jia Liu, Yutai Zhao et al. (+6 more)
Spatiotemporal mode-locking (STML) in multimode fibers introduces spatial degrees of freedom for ultrashort pulse generation, yet flexible manipulation of transverse mode compositions within multimode
solitons remains challenging. Here, we propose a spectrum-to-mode mapping strategy in multimode Mamyshev oscillators (MOs) to selectively synchronize specific transverse modes through synergistic cross-phase modulation and offset spectral filtering. Meanwhile, four-wave mixing acts to stabilize intermodal phase relationships, facilitating selective STML characterized by diverse mode compositions with matched group velocities. Spatiotemporal
solitons containing the pure LP01 mode, degenerate LP11 modes, or LP02+LP21 composite modes are selectively realized and mapped across the parameter space spanned by intracavity gain and filter detuning. Furthermore, intracavity collisions between coexisting mode groups with disparate group velocities are demonstrated to enable dynamic mode selection. Beyond the simulation of six modes in graded-index multimode fibers, selective STML is also demonstrated in MOs based on step-index multimode fibers and fibers supporting more transverse modes, confirming the generality of our approach. This strategy offers a versatile and robust pathway for transverse mode regulation and provides new insights into full dimensional structured light manipulation in multimode ultrafast fiber
lasers.
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All authors Changfeng Wang, Jia Liu, Yutai Zhao, Ran Xia, Wenjun Ni, Chunyong Yang, Xiahui Tang, Gang Xu, Perry Ping Shum