Soft Condensed Matter
Kinetics of ferritin crystal formation and melting in acoustically levitated droplets
Anita Girelli, Iason Andronis, Aigerim Karina et al. (+5 more)
Understanding
protein crystallization pathways is essential for controlling crystallization in structural biology, materials science, and pharmaceutical applications. Classical nucleation theory does not fully capture crystallization processes for several
proteins, including ferritin. Here, we combine acoustic levitation with small- and wide-angle X-ray scattering (SAXS and WAXS) to monitor ferritin crystallization in evaporating aqueous polyethylene glycol (PEG) solutions. Acoustic levitation rapidly drives the droplets through a broad range of
protein and
polymer concentrations, enabling time-resolved measurements of crystallization during evaporation. The scattering data show that ferritin
crystals form during evaporation and subsequently lose their crystalline order upon further dehydration. Varying the PEG molecular weight switches between distinct crystallization pathways: one dominated by attractive
protein-
protein interactions and another dominated by repulsive interactions and excluded-volume effects. Furthermore, we find that lower molecular weight PEG (1000 g/mol) suppresses the dehydration-induced loss of crystalline order observed for higher molecular weight PEG (6000 g/mol), providing a simple strategy for improving
protein crystal stability.
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All authors Anita Girelli, Iason Andronis, Aigerim Karina, Sampad Bag, Lennart Bergström, Tomás Plivelic, Felix Roosen-Runge, Fivos Perakis
General Relativity and Quantum Cosmology
Constraining Modified Mass-to-Horizon Cosmology Through Primordial Inflationary Observables
A. Sheykhi, G. G.Luciano and A. Benkrane
We investigate slow-roll inflation in a modified cosmological framework inspired by a generalized mass-to-horizon relation (MHR), $M=\gamma {c^2 L^n}/{G}$, where $n$ is a real parameter and $\gamma$ a dimensional constant. Using Padmanabhan's emergence paradigm, we derive the modified Friedmann equations for a flat FRW universe and analyze the dynamics of a canonical scalar field (inflaton) under the slow-roll approximation. We study the resulting inflationary phenomenology for power-law and Starobinsky potentials. For power-law potentials, the MHR modification fails to reconcile these models with current CMB constraints on $r$ and $n_s$. In contrast, Starobinsky inflation exhibits significant sensitivity to deviations from $n=1$. A perturbative analysis ($n=1+\Delta$) yields corrections to inflationary observables. We observe that the scalar power-spectrum normalization, under a fixed-Starobinsky prescription, imposes the stringent constraint $0.960 \lesssim n \lesssim 1.040$ for $N=60$ efolds. This is considerably tighter than spectral-index bounds. Our results establish inflation, particularly Starobinsky-like models, as a sensitive probe of generalized horizon thermodynamics and departures from standard MHR scaling.
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High Energy Astrophysical Phenomena
Nonbirefringent model of orthogonal polarization modes in radio pulsars - New view on S swing and mode structure in pulsar beam
J. Dyks and A. Frankowski
Two orthogonal polarization modes observed in
radio pulsar signals have long been attributed to proper modes of wave oscillation in strongly magnetized
plasma. Yet it has been shown recently that they show up readily for extended emission regions that produce incoherently-superposed polarization signal. In this paper we present a two-dimensional polarization model based on incoherent superposition of
radio signals. The model involves a single proper mode, say the O mode, but leads to the appearance of two orthogonal polarization tracks and naturally produces the triple form of polarization mode segregation in averaged profiles (central mode flanked on boths sides by another mode), as well as the displacement of modes in latitude, previously inferred from beam mapping. In the case of conal emission regions, the modelled polarization tends to mimic general polarization properties of the rotating vector model (RVM). However, the reason for this is the
symmetry of the emission region - not the usual projection of dipolar
magnetic azimuths. Thus the emerging RVM parameters reveal geometry of the emission region, not of the dipolar
magnetic field. The results strongly support the vital role of nonbirefringent modal effects in
radio pulsar profiles. Two proper modes may not be needed to explain observations of two orthogonal polarization tracks.
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General Relativity and Quantum Cosmology
Quasi-isotropic Asymptotic Expansions in Varying Speed of Light Cosmologies
Dimitrios Trachilis
We generalize the quasi-isotropic solution of the Einstein equations near a cosmological initial singularity to models with a varying speed of light and/or a varying gravitational 'constant'. We construct a formal asymptotic series expansion in a synchronous reference system, taking into account the additional degrees of freedom introduced by the two varying 'constants'. By applying the Landau-Lifshitz quasi-isotropic method, we go beyond the standard results of previous studies that based on the Friedmann-Lemaître-Robertson-Walker (FLRW) model, providing a more general asymptotic analysis of varying speed of light cosmologies. We show that the resulting solutions do not contain the required number of arbitrary functions to qualify as general solutions of these theories.
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Mesoscale and Nanoscale Physics
Enhancing charge stability of Ge quantum well heterostructures via SiGe layer composition engineering
Ding-Ming Huang, Jun-Hang Liu, Han Gao et al. (+10 more)
Composition modulation is a powerful technique for designing materials with tailored properties, fueling the development of advanced
semiconductor devices. In this work, we have implemented this technique into Ge
quantum well
heterostructures, offering a promising avenue to address the critical challenge of charge stability in
spin qubit devices. Harnessing the atomic-scale precision of molecular beam epitaxy, we have engineered the band structure of the SiGe top barrier via graded composition modulation, thereby reducing charge accumulation states at the SiGe-dielectric interface and strengthening the effective confinement to the hole gases in the Ge
quantum wells. The enhanced charge stability of composition-modulated SiGe/Ge
quantum well
heterostructures is confirmed in
Hall devices, featuring an enlarged stable gate voltage range. We have further fabricated
quantum dot devices from the composition-modulated SiGe/Ge
quantum well
heterostructures and observed remarkably low charge noise with an averaged amplitude of $0.46\,\mathrm{\mu eV}/\mathrm{\sqrt{Hz}}$ at $1\,\mathrm{Hz}$—the lowest reported value for Ge
quantum wells grown on silicon. This exceptional charge stability of the
quantum dots persists in the few-hole regime, with no observable voltage drift over $\sim$hours. With reduced charge noise and enhanced energy stability, composition-modulated SiGe/Ge
heterostructures exhibit significant potential for applications in building high-performance
quantum devices, including
spin qubits with a long coherence time.
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All authors Ding-Ming Huang, Jun-Hang Liu, Han Gao, Jie-Yin Zhang, Jian-Huan Wang, Fang-Ze Liu, Xin-Yu Zhou, Yi Luo, Bin-Xiao Fu, Xiao-Fei Liu, Ji-Yin Wang, Jian-Jun Zhang, H. Q. Xu
Solar and Stellar Astrophysics
Non-axisymmetric Transport of Magnetic Flux Tubes: A Mechanism for Joy's Law and Poloidal Field Generation via Meridional Flows
Andrey G. Tlatov
We present a new scenario for the
solar $\alpha\omega$-dynamo based on the interaction of asymmetric
magnetic flux tubes with the near-surface meridional flow. Standard thin flux tube simulations indicate that the radial gradient of differential rotation ($\partial\Omega/\partial r > 0$) breaks the spatial
symmetry of emerging $\Omega$-loops. The leading (western) leg becomes nearly vertical, while the trailing (eastern) leg is heavily stretched and flattens along the longitude. Upon emergence at the photosphere, the horizontal meridional flow toward the poles acts more efficiently on the trailing leg because the efficiency of the hydrodynamic entrainment by the
plasma (the “sail effect”) is directly proportional to the total spatial length of the
magnetic flux tube arc elements. This creates a differential torque that drives the trailing sunspot poleward while the leading sunspot remains anchored due to its compact spatial geometry. Our model yields a tilt angle
evolution rate of $\approx 0.3^\circ\,\mathrm{day}^{-1}$ at a latitude of $20^\circ$ for a bipolar separation of $15^\circ$, reproducing Joy's law without invoking the classical Coriolis-driven twist during the rise phase.
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Optics
Two-step high-accuracy microwave frequency measurement and time-frequency analysis based on optical frequency combs
Wentao Ma, Taixia Shi, Chi Jiang et al. (+1 more)
Broadband microwave frequency measurement and time-frequency analysis are crucial for applications such as electronic warfare. However, when it comes to ultra wideband signal analysis, traditional electronic methods have high analysis accuracy, but intrinsic electronic bottlenecks limit their real-time analysis. Here, we propose and experimentally demonstrate a two-step microwave frequency measurement and time-frequency analysis method based on optical frequency combs. The system first performs coarse frequency localization over the 0-40 GHz range using stimulated-Brillouin-scattering-assisted frequency-to-time mapping (FTTM) and dual-comb channelized reception. The dual-comb is then reapplied for downconverting the signal under test, followed by digital signal processing to achieve high-accuracy unambiguous frequency extraction. Experimental results show that the system achieves mean single-tone frequency measurement errors of less than 10 kHz over 0-40 GHz. We further experimentally measure multi-tone, linearly frequency-modulated, and V-shaped frequency-modulated signals, demonstrating the proposed method's capability for analyzing complex signals.
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All authors Wentao Ma, Taixia Shi, Chi Jiang, Yang Chen
Materials Science
Interplay of spin-lattice and electronic coupling far above Neel ordering in 2D antiferromagnetic CrPS4 and its interface manifestation
Divya Jangra, Binoy Krishna De, Mukesh Kumar Dasoundhi et al. (+13 more)
A short-range
spin correlation driven, strongly intercoupled
spin-
phonon-electronic state far above TN (~38K) is identified in the low dimensional van der Waals antiferromagnet CrPS4. Temperature-dependent Raman spectroscopy reveals
spin-
phonon coupling persisting up to T*~120K, concomitant with local
lattice distortion. The setting of vibronic progression in photoluminescence spectra suggests the strengthening of electron-
phonon coupling around T*. Furthermore, both the electrical transport and optoelectronic response also change significantly at T*. The results indicate that
spin-
phonon coupling above TN in CrPS4 originates from local
lattice distortion induced by short range
magnetic correlations which in turn enhances the electron-
phonon interaction. Furthermore, using a CrPS4/In2Se3
heterostructure, we demonstrate that the anomaly associated with the coupled degrees of freedom in CrPS4 also influences the adjacent In2Se3 layer. The
lattice dynamics of In2Se3 is significantly modified across the
magnetic anomaly of CrPS4, and the coupled dynamics is observed at T*. These interfacial manifestation opens up new possibilities for achieving correlated multifunctionalities in artificially designed
heterostructure.
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All authors Divya Jangra, Binoy Krishna De, Mukesh Kumar Dasoundhi, Sourav Chowdhury, Pragati Sharma, Kartick Biswas, Arup Basak, Dheeraj Kumar Gupta, Koushik chakraborty, Praveen Kumar Velpula, Pavan Nukala, U. Chandni, Arvind Kumar yogi, Mukul Gupta, Markus Hucker, Vasant G. Sathe
High Energy Physics (Phenomenology)
Doubling down on proton structure: what double parton scattering can and cannot tell us about partonic separation
Andrew Fowlie, Arthur Moraes and Hao Yang
Double parton scattering provides a unique probe of
proton structure and is commonly characterized by the effective cross section $\sigma_\mathrm{eff}$. We examine, under the factorized ansatz for the double-parton-scattering cross section and without assuming any specific parametric form for the transverse profile, what the effective cross section can reveal about the transverse separation, $r$, between partons in the
proton. We derive a sharp lower bound on the transverse partonic separation, $\langle r^2\rangle \ge 4\sigma_\mathrm{eff}/(9\pi)$, and demonstrate through explicit counterexamples that previously posited upper bounds do not hold. Our results establish, within the effective-cross-section parametrization of double parton scattering framework, that $\sigma_\mathrm{eff}$ can provide a sharp lower bound on partonic separation but cannot provide a general upper bound.
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Astrophysics of Galaxies
Black Hole-Galaxy Correlations in Cluster Zoomed-in Simulations: GIZMO-SIMBA and TNG-Cluster
Hangxin Pu, Antonios Katsianis, Weiguang Cui et al. (+8 more)
We investigate the co-
evolution of supermassive black holes (SMBHs) and central
galaxies in massive clusters using the GIZMO-SIMBA and TNG-Cluster zoom-in simulations at $z=0-5$. We find that the distinct subgrid physics of these two models suggest fundamentally different evolutionary pathways. On the one hand, GIZMO-SIMBA, employs torque-limited
accretion and predicts a supply-driven scenario where the SMBHs rapidly assemble synchronized with dark matter
halo ($M_{200c}$) growth (i.e. the
halo mass-BH mass relation is set by $z=3.0$ and similar to the present-day relationship). On the other hand, TNG-Cluster, exhibits a feedback-regulated growth phase delayed by an early thermal suppression. While both models successfully reproduce some local black hole-
galaxy scaling relations, they imply significantly different
evolution for these relations. Analysis of the BH mass-gas mass ratio relations suggests that TNG-Cluster's isotropic kinetic winds efficiently deplete cold gas, resulting in a "hard quench" of
star formation. In the black hole
accretion rate (BHAR)-
star formation rate (SFR) relation we find that both simulations successfully reproduce the decoupling of BHAR and
star formation observed in recent massive cluster ellipticals. The divergent evolutionary trends emphasize the importance of the multiphase intracluster medium; while these subgrid models do not have the necessary resolution and employ distinct formalisms, the sustained BHAR in quenched systems resemble outcomes broadly consistent with modern multiphase feeding paradigms such as chaotic cold
accretion in turbulent cluster cores. Furthermore, we demonstrate that for both models, black hole mass is a primary regulator of atomic and molecular gas depletion in
galaxy clusters.
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All authors Hangxin Pu, Antonios Katsianis, Weiguang Cui, Romeel Davé, Massimo Gaspari, Weishan Zhu, Xiaohu Yang, Jinyi Shangguan, Qingshan Wang, Ying Tang, Yuchang Li
Statistical Mechanics · Cross-listed from cs.IT
Physics of Information Geometry - Part II: Small-Step Active Inference on the Probability Simplex
C. Emre Koksal and Deniz Sargun
This paper is the second in a two-part investigation of the physics of information geometry. While Part I develops a physical foundation for distributional motion on the probability simplex, the present paper studies how that framework manifests in active inference. The treatment is fully self-contained and does not require familiarity with Part I. We focus in particular on active inference through small distributional steps and the
geometric structure induced by such local motion. Starting from an initial distribution, an
agent evolves its belief state toward a final target distribution through a sequence of constrained updates. We define a relative free energy functional with respect to the preferred distribution and extend it to a relative potential energy analogous to the Helmholtz/Gibbs free-energy decomposition. The
evolution is subject to a per-step kinetic constraint expressed through the Kullback-Leibler (KL) divergence between consecutive distributions, which serves as a discrete kinetic energy on the probability simplex. Using the information-
geometric Pythagorean
theorem on KL balls, we show that sufficiently small local moves dominate large direct jumps, and that greedy maximization of free-energy reduction is globally optimal under the kinetic constraint. This leads to a sequential variational principle in which the optimal trajectory minimizes the associated Lagrangian of the optimization problem. Similar to classical mechanics, the Lagrangian takes on the form as the difference between the kinetic and potential terms, establishing a least-action principle for distributional motion on the simplex. The resulting optimal update admits a closed form as an exponentially tilted version of the current distribution toward the preferred distribution, parametrized by an inverse-temperature-like multiplier. We further extend the framework to incorporate state-dependent geodesic...
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Cosmology and Nongalactic Astrophysics
SMART : Spherical Mass ApeRture Toolkit
Igor Bezmaternykh, Sandrine Pires, Nicolas Dagoneau et al. (+3 more)
The aperture mass filter is a widely used tool in weak
lensing studies. While previous surveys have typically relied on the flat-sky approximation, forthcoming Stage IV surveys such as Euclid will cover sufficiently large areas to require the construction of curved-sky aperture mass maps. In this paper, we extend the shear-based aperture mass formalism to the sphere and introduce a software package for a fast and precise computation of spherical aperture mass maps from the shear field, defined directly on the celestial sphere. Unlike existing approaches, our method does not rely on planar projections and does not require the reconstruction of convergence maps. The software provides four different implementations, all of which are independent of the choice of aperture mass filter function. Starting from the brute-force approach, whose computational cost renders it impractical for future surveys covering more than 10,000 deg2, we investigate alternative
galaxy-grouping strategies to improve computational efficiency. We demonstrate speed-up factors of up to 40 at a resolution of NSIDE = 4096 while achieving significantly higher precision than existing state-of-the-art methods. In particular, we show that the spherical shear-based implementations using a pixel-based approach outperforms the existing methods in terms of both precision and computational time. Finally, we show that, for weak-
lensing cluster detection, the cluster sample produced using the spherical shear-based aperture mass method consistently outperforms those obtained using projected shear-based approaches in the purity-completeness plane, while simplifying the resulting selection function. Our spherical mass aperture software, called SMART, is made available on GitHub.
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All authors Igor Bezmaternykh, Sandrine Pires, Nicolas Dagoneau, Gabriel W. Pratt, Loris Chappuis, Gavin Leroy
High Energy Physics (Phenomenology)
Twist decomposition of exclusive heavy meson production cross sections
Mariusz Sadzikowski
We study the twist decomposition of the total cross sections for exclusive heavy vector
meson electroproduction and photoproduction in the $\gamma^\ast p$ processes, within the leading logarithmic $1/x$ BFKL formalism. The Mellin transforms of the impact factors of the vector
meson are calculated. We show that the higher twist contributions are strongly suppressed in the low-$x$ kinematical regime. Possible enhancement of the higher twists effects for
nuclei targets is discussed.
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Instrumentation and Methods for Astrophysics
The EDD Radio Astronomy Backend Framework
Ewan D. Barr, Amit Bansod, Jan Behrend et al. (+16 more)
Modern digital
radio astronomy receivers produce increasingly wide-bandwidth, high bit-rate data streams that necessitate the development of flexible, scalable, and maintainable backend processing and recording systems. Historically, such backend instrumentation has been tightly coupled to
telescope observing modes, limiting reuse between observatories and science cases. We present the Effelsberg Direct Digitisation (EDD) backend framework, a software-defined architecture for constructing real-time
radio astronomy backends on commodity off-the-shelf computing infrastructure. We describe its design, implementation, supported observing modes, and operational deployments. EDD separates a common core framework from plugin-provided observing capabilities. The core provides orchestration,
telescope interfaces, pipeline lifecycle management, monitoring, and deployment tooling, while plugins implement processing pipelines for specific observing modes. The framework is designed to support both single-dish and interferometric instruments through site-specific configuration and plugin selection. EDD currently supports spectroscopy and spectropolarimetry,
pulsar timing and searching, baseband recording, very long baseline interferometry, correlation, and beamforming. Operational deployments include the Effelsberg 100-m
telescope, the SKA-MPI prototype dish, the Thai National
Radio Telescope, and the ARGOS interferometric prototype array. By separating common services, observing-mode plugins, and site-specific configuration, it allows backend capabilities to be deployed across heterogeneous
telescope environments and provides a community resource for broadband
radio astronomy instrumentation.
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All authors Ewan D. Barr, Amit Bansod, Jan Behrend, Weiwei Chen, Niclas Esser, Yungpen Men, Tobias Winchen, Jason Wu, Uwe Bach, Claus Connot, Matthias Heininger, Jedrzej Jawor, Christoph Kasemann, Michael Kramer, Alex Kraus, Eddy Nussbaum, Oliver Polch, Jan Wagner, Gundolf Wieching
Mathematical Physics
The kinematic structures and the inertial geometry of a moving charge
César S. López-Monsalvo
We ask how much of the geometry a charged particle moves in is fixed by its motion, and how much a particle must bring. We ask of a
symplectic structure only that it relate velocity to momentum as Hamilton's equations do, and we ask it of every energy at once. In particular, we show that the structures meeting that demand are the canonical one and its twists by a closed two-form of the base. A field provides the two-form, a particle the multiplier before it, which we identify constitutively with its charge. Thus, a single energy governs a family of structures, and each particle takes the one its charge fixes. We then ask what a particle must bring to be given a momentum, and we show that the degree of that map settles the degree at which a field enters Newton's Second Law. An antisymmetric bilinear form returns no Lorentz force, whilst a Randers metric returns one — a length whose difference from a Riemannian one is linear in the velocity. Moreover, we find that metric already within the twisted structure, as its primitive over a level of the free energy, and its law of transport to be nonlinear, no affine connection being known to serve. Under an indefinite signature the length parts from the dynamics, and the extremals turn from shortest to longest. On the round sphere a monopole flux leaves no such metric, whilst the transport remains and prequantisation, given a unit of action, restricts the charge to a
lattice. In this manner, we conclude that each charge-to-mass ratio receives a geometry of its own, so that by a functionalist criterion none of them is the spacetime of a charged particle.
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Quantum Physics
Finite-blockade dynamics of a three-qubit ccz gate in neutral-atom arrays
Paramjeet Banger and Ajay Wasan
We present a theoretical study of finite-blockade dynamics in a symmetric three-neutral-atom system, providing a framework for understanding high-fidelity multiqubit
quantum operations. The transition from the finite- to the strong-blockade regime is systematically investigated to examine the effects of finite Rydberg blockade. Using a single Gaussian
laser pulse, we analyze the complete gate dynamics while explicitly accounting for population leakage into non-computational Rydberg states. By exploiting the permutation
symmetry of the system, we construct a
symmetry-adapted
Hamiltonian that reduces the computational complexity while preserving the exact dynamics. This enables a systematic investigation of the interplay among the Rabi frequency,
laser detuning, and Rydberg blockade strength, leading to the identification of optimal operating regimes with high fidelity, fast gate operation, and suppressed leakage. We further quantify the dominant error mechanisms, including phase errors, population leakage, and finite Rydberg-state lifetimes, and evaluate their impact on the gate fidelity. Our results demonstrate experimentally accessible high-fidelity gate operation and provide practical guidelines for multi-
qubit quantum computing.
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Quantum Physics
Optimal T-Count for Block Encodings of Fermionic and Spin Hamiltonians
Jiaxin Ma, Kevin J. Joven and Yuan Liu
We determine the non-Clifford $T$-gate cost of constructing block encodings of structured fermionic and
spin Hamiltonians in a
unitary Clifford$+T$ model, when arbitrarily many clean ancillas and unrestricted block-encoding subnormalization are allowed, but without mid-
circuit measurements or classical feed-forward. Our main technical tool is an ancilla-compression
theorem: any block encoding of an $n$-
qubit operator with $a$ clean ancillas and at most $s$ $T$ gates can be compressed to use at most $\min\{a,n+2s\}$ ancillas, without increasing the absolute error or $T$-count. For general second-quantized
Hamiltonians with bounded one- and two-body coefficients, at operator-norm block-encoding error $\epsilon$, a volume-covering argument combined with
circuit counting gives the worst-case lower bound $\Omega(n^2\sqrt{\log(n^4/\epsilon)})$, matching the existing upper bound at fixed precision. For the bond-dependent Kitaev honeycomb family on $n$
spins, we obtain independent lower bounds $\Omega(n)$ from stabilizer nullity and $\Omega(\log(1/\epsilon))$ from one-
qubit state preparation, established using different
Hamiltonian instances. Together with an explicit LCU construction, they give the tight worst-case scaling $\Theta(n+\log(1/\epsilon))$. As an application, we evaluate the $T$-count of a
Hamiltonian simulation
circuit based on
quantum singular value transformation, with each block-encoding query compiled separately. When phase synthesis and controlled queries add at most constant-factor overhead, the simulation $T$-count scales as the query count times the optimal $T$-count per query.
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High Energy Physics (Phenomenology)
Qubit-Qutrit Quantum Tomography of hadronic $\Lambda\phi$ and $\Lambda K^{\ast 0}$ systems
Veronica Kanachova, Feng Liu and Zhoudunming Tu
Quantum-information observables have emerged in recent years as new tools in
nuclear and particle physics, from
entanglement in top-
quark pairs to
spin correlations in $\Lambda\bar{\Lambda}$ production. Extending these studies to unequal-
spin hadronic final states poses a fundamental challenge: the $6\times6$ density
matrix of a
qubit-qutrit system contains 35 independent
spin parameters, but the decays of $\Lambda V$ pairs, with $V=\phi$ or $K^{*0}$, provide access to only 23 due to the hidden vector polarization from the strong decay. In this Letter, we formulate a
qubit-qutrit
quantum tomography (QQQT) technique for these
spin-$\tfrac{1}{2}\otimes1$ systems and establish exact criteria for
entanglement certification from the incomplete density
matrix. Compared with the $\Lambda\bar{\Lambda}$ system, QQQT of $\Lambda\phi$ and $\Lambda K^{*0}$ provides a new probe of nonperturbative QCD hadronization, enabling a direct comparison of the
spin evolution of entangled
quark pairs produced from the
vacuum as they hadronize into a
baryon or a vector
meson.
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Solar and Stellar Astrophysics
Statistical evidence for linear combination frequencies in {\gamma} Doradus stars being nonlinear resonant modes
Yanqi Mo, Weikai Zong, Xuan Wang et al. (+4 more)
The quest for the origin of linear combination frequencies in pulsating
stars is critical for mode identification and subsequent seismic modeling. Hybrid {\gamma} Doradus (Dor)
stars provide a crucial testbed for such investigations due to their rich frequency content in both
gravity (g) and pressure (p) modes. Here, we performed a comprehensive survey of 608 Kepler {\gamma} Dor
stars, detecting 81,265 frequencies, and identifying 1,895 harmonics and 45,968 combinations involving two parent frequencies. Our results suggest that the proportion of linear combinations increases with the frequency number in each {\gamma} Dor
star, leveling off at approximately 75%. The majority of the parent-to-child amplitude ratios are distributed between 100 and 10,000, peaking between 2,000 and 4,000. Moreover, the amplitude ratios, involving two g-mode parents, are found to escalate with increasing combination frequency. These values are at least an order of magnitude higher than those predicted by nonlinearity distortion of the light curve, whereas they align well with those of nonlinear resonant coupling. Our findings suggest that a significant portion of combination frequencies are likely intrinsic modes under resonant conditions rather than products of surface
geometric distortions, offering new insights that warrant systematic investigations across other types of pulsating
star.
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All authors Yanqi Mo, Weikai Zong, Xuan Wang, Jian-Ning Fu, Xiao-Yu Ma, Mingfeng Qin, Stéphane Charpinet
General Relativity and Quantum Cosmology
Electrovacuum Black Hole Uniqueness
Qing Han, Marcus Khuri, Gilbert Weinstein et al. (+1 more)
We prove the black hole uniqueness
conjecture in the axially symmetric, stationary, electrovacuum setting, subject to the refined asymptotic analysis of the associated singular harmonic maps, which includes an analyticity hypothesis at the axes. More precisely, it is shown that any asymptotically flat solution of the Einstein–Maxwell equations in this class, with more than one black hole horizon component is either: Majumdar–Papapetrou, up to a duality rotation, in which case all logarithmic angle defects vanish, or every finite axis rod logarithmic angle defect is strictly negative and hence every interaction force is strictly attractive. The proof extends the singular harmonic map method used for
vacuum Kerr uniqueness in [18].
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All authors Qing Han, Marcus Khuri, Gilbert Weinstein, Jingang Xiong
Mesoscale and Nanoscale Physics
Fingerprints of Excitonic Collective Modes in the Two-Dimensional Electron Gas
Jakob Wolff, Silvana Botti, Lucia Reining et al. (+1 more)
The two-dimensional homogeneous electron gas (2D HEG) is a prototype system of fundamental interest that can be realized experimentally over a wide range of densities. Here, we investigate its collective charge excitations at low densities, using time-dependent density functional theory. We demonstrate that, beyond traditional plasmons, new collective excitonic modes emerge for a Wigner-Seitz radius larger than $r_{\mathrm s} \approx 1$. These excitonic modes leave characteristic fingerprints in experimentally accessible quantities, namely, asymmetric peak structures in the loss function and very strong Friedel-like oscillations in the static linear density response that increase when the system approaches a regime of instability. Indeed, at low enough densities the collective modes cross the zero energy axis, indicating an instability of the paramagnetic 2D HEG towards the formation of a charge-density-wave phase with excitonic origin. These findings provide valuable insights for the experimental detection of excitonic collective modes in tunable 2D electron systems and contribute to the fundamental understanding of many-body effects in low-density electron gases.
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All authors Jakob Wolff, Silvana Botti, Lucia Reining, Matteo Gatti
Medical Physics
Phase-contrast micro-CT for intra-operative breast tumour margin assessment using a microfocus x-ray source and photon-counting detector
Michelle K. Croughan, Timur E. Gureyev, Jane Fox et al. (+5 more)
Objective: Intra-operative tumour margin assessment during breast-conserving surgery requires rapid, high-resolution imaging of excised tissue, allowing the
surgical team to take appropriate action within a single operation. This study evaluates a custom propagation-based phase-contrast micro-computed
tomography (micro-CT) system designed to meet these clinical constraints without specialised optical elements. Methods: The experimental setup pairs a microfocus x-ray source with a
photon-counting detector in a cone-beam geometry. We explore how the spatial coherence of the source can provide propagation-based phase contrast – with no additional specialised optical elements – and balance this against maximising the x-ray flux of the cone-beam geometry. System performance was evaluated across two anode target materials and filtration configurations at various tube power settings. Imaging capabilities were validated using anthropomorphic breast tissue phantoms and a formalin-fixed paraffin-embedded (FFPE) breast tissue specimen, with reconstructions compared against gold-standard histology. Results: An unfiltered tungsten target operated at 40 kVp yielded optimal image quality. The optimised system achieved high-resolution CT reconstructions of a 5 cm diameter sample with an isotropic voxel size of 40.7 $\upmu\text{m}$ in a scan time of 12 minutes. Reconstructed volumes demonstrated strong visual correlation with corresponding histology slides. Conclusion: Combining a microfocus source with a
photon-counting detector enables high-resolution, phase-contrast micro-CT within a clinically viable timeframe, demonstrating strong potential for intra-operative margin assessment.
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All authors Michelle K. Croughan, Timur E. Gureyev, Jane Fox, Mikkaela McCormack, James A. Pollock, Dominic Jurkschat, Stephanie A. Harker, Marcus J. Kitchen
Materials Science
High-Performance Scaled P-Type SnOx Transistor by Atomic Layer Deposition with CFET Integration
Ziheng Wang, Wen He, Chen Gu et al. (+8 more)
The development of high-performance p-type
oxide semiconductors is essential for realizing complementary logic for monolithic 3D integration, yet p-type
oxide semiconductors still exhibit substantially inferior performance compared with their n-type counterparts. In this work, we demonstrate high-performance p-type SnOx transistors by atomic layer deposition (ALD), as back-end-of-line compatible devices for monolithic 3D integration. The SnOx transistors exhibit high field-effect mobility of 6.9 cm2/Vs, low subthreshold swing (SS) of 185 mV/dec, decent on/off ratio (ION/IOFF) of 1.8*104 and high bias stability. By scaling the channel length down to 80 nm, a high on-current of 38.7 mA/mm at VDS of -1 V is achieved. It is understood that precursor and reaction engineering to suppress Sn4+ component in SnOx film are the key for performance enhancement. Furthermore, a complementary field-effect transistor with ALD SnOx p-FET vertically stacking on ALD In2O3 n-FET is also demonstrated, achieving maximum voltage gain of 21 V/V at VDD of 4 V. These findings suggest ALD SnOx as a promising candidate for scaled high-performance BEOL p-type transistors.
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All authors Ziheng Wang, Wen He, Chen Gu, Kai Jiang, Liankai Zheng, Jinxiu Zhao, Zhiyu Lin, Xiangjun Liu, Di Geng, Ling Li, Mengwei Si
Applied Physics
Scattering-robust Imaging of Azimuthal Features with Enhanced Resolution
Nilakshi Senapati, Abhinandan Bhattacharjee and Anand K Jha
Imaging through scattering media remains a long-standing challenge in numerous real-world applications, ranging from medical imaging to long-distance sensing. Recently, illumination consisting of a single orbital angular momentum (OAM) mode, which is structured in the azimuthal coordinate, has been shown to provide enhanced resolution for imaging objects with azimuthal features, with the resolution becoming maximum at an optimal OAM value. However, in the presence of scattering, single-mode fields, which are spatially fully coherent, cause the imaging resolution to decrease significantly due to speckle formation. In this work, we employ azimuthally partially coherent fields and experimentally demonstrate imaging of azimuthal features with enhanced resolution in the presence of scattering. We show that lower degree of azimuthal coherence in such illumination leads to increased robustness against scattering while the azimuthal structure of the illumination ensures enhanced resolution. We derive the condition for best imaging resolution, and we report increase of imaging contrast in scattering from about 7% to 50% as the illumination is changed from a single-mode fully coherent field to that of an azimuthal partially coherent field.
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Fluid Dynamics
A Novel Multi-fidelity Surrogate for Efficient Turbine Design Optimization
Qineng Wang, Liming Song, Zhendong Guo et al. (+2 more)
To solve the turbine design optimization problems efficiently, surrogate-based optimization (SBO)
algorithms are frequently used. To further reduce the cost of turbine design, the multi-fidelity surrogate (MFS) based optimization is proposed by the researchers, who resort to augmenting the small number of expensive high-fidelity (HF) samples by a large portion of low-fidelity (LF) but cheap samples in surrogate modeling and optimization process. Nonetheless, according to our observations, the MFS based optimization sometimes can only have better convergence rate at the early stage of optimization process, but yielding worse final solution than the single-fidelity surrogate (SFS) based optimization that uses high-fidelity samples alone. The reason behind can be explained as follows. With the increase of HF samples in the optimization process, the LF samples can cause negative effect and therefore misleading the optimization search. To address the above issue, an ensemble weighted multi-fidelity surrogate (EMFS) is proposed. Specifically, the density-based spatial clustering of applications with noise (DBSCAN) is used to detect the region where the MFS cannot build a more accurate surrogate, and a local SFS is built there. Then, an EMFS is built by combining the MFS and SFS with adaptive weights, which is used to guide the optimization process. The related
algorithm is named as multi- and single-fidelity surrogate fused optimization, i.e., MSFO. Through tests on GE-E3 blade optimization and the film cooling layout design of a turbine endwall, the effectiveness of proposed MSFO is well demonstrated.
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All authors Qineng Wang, Liming Song, Zhendong Guo, Jun Li, Zhenping Feng
Fluid Dynamics
A Novel Multi-fidelity Surrogate for Turbomachinery Design Optimization
Qineng Wang, Liming Song, Zhendong Guo et al. (+2 more)
Turbomachinery design optimization involves expensive black-box problems. Sample-efficient multi-fidelity optimization (MFO) offers an efficient solution. By utilizing multi-fidelity surrogates (MFS), the MFO
algorithm can use fewer high-fidelity samples aided by low-fidelity samples to establish an accurate surrogate model. However, when MFS is used in sequential sampling optimization, it has been observed that the final optimal solution obtained by single-fidelity optimization (SFO) is better than that of MFO, even though MFO performs better at the early stages. This can be attributed to the assumption of an even and nested distribution of samples, which is incorrect when using a sequential adding strategy. To address these issues, we propose a novel
algorithm called multi-single-fidelity optimization (MSFO) to overcome the limitations of the conventional MFO procedures. In the surrogate establishment of MSFO, we use the density-based spatial clustering of applications with noise (DBSCAN) method to detect local areas where low-fidelity samples are no longer effective. A combination of both global MFS and local single-fidelity surrogate model, built using high-fidelity samples alone, is used to establish an ensemble, which improves the anti-interference ability of the
algorithm against misleading low-fidelity data. The effectiveness of the MSFO
algorithm is verified first on numerical
benchmark functions. Then, the
algorithm is used to optimize the aerodynamic profile of a turbine and the film cooling layout design of a turbine endwall. Here, high-fidelity sample sources are obtained from fine-mesh CFD simulations, whereas low-fidelity sample sources are obtained from the same simulations run on a coarser mesh. The results demonstrate that our MSFO
algorithm performs significantly better than the conventional SFO and MFO processes, with a higher level of robustness.
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All authors Qineng Wang, Liming Song, Zhendong Guo, Jun Li, Zhenping Feng
Astrophysics of Galaxies
Nitrogen-Loud Quasars from the Dark Energy Spectroscopic Instrument. I. Sample Selection and Basic Properties
Shuo Zhai, Wei-Jian Guo, Yong-Jie Chen et al. (+4 more)
We present the largest sample to date of nitrogen-loud (N-loud)
quasars with strong broad N IV] $\lambda1486$ and/or N III] $\lambda1750$ emission lines over the
redshift range $1.6 < z < 4.3$, selected from the Dark Energy Spectroscopic Instrument (DESI) Data Release 1. The final sample contains 1,993 N-loud
quasars, corresponding to about 1.2% of the parent
quasar sample. The $L_{1450}$ distribution of the N-loud
quasars is broadly similar to that of the DESI parent sample, but their
redshift distribution is distinct, with a stronger concentration around $z \sim 2.5$–3. Their composite spectrum displays a broadly similar UV continuum shape to that of the parent
quasars, while showing significantly enhanced broad nitrogen emission features, including N V, N IV], and N III]. Other metal emission features also show a moderate enhancement. Relative to a control sample matched in
redshift and UV continuum luminosity, the N-loud
quasars show systematically narrower broad C IV and Mg II emission lines, lower single-epoch virial black hole masses, and higher Eddington ratios, suggesting that N-loud
quasars may preferentially appear during a relatively rapid black hole
accretion phase. The
radio-loud fraction is 10.1%, with the highest fraction among objects exhibiting both N III] and N IV] emission. The catalog provides a statistical baseline for future studies of nitrogen enhancement and its physical origin.
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All authors Shuo Zhai, Wei-Jian Guo, Yong-Jie Chen, Zhi-Qiang Chen, Haining Li, Jian-Min Wang, Gang Zhao
Nuclear Theory
Classification of fission modes in $^{236}$U using a six-dimensional Langevin approach
K. Okada, K. Nishio, T. Wada et al. (+1 more)
Thermal
neutron-induced fission of $^{235}$U is studied using a six-dimensional Langevin approach based on the Cassini shape parametrization. Scission events are classified into Asymmetric 1 (AS1), Asymmetric 2 (AS2), and Superlong (SL) fission modes by applying the $k$-means
algorithm to the fragment mass and the quadrupole deformations of both fragments. For each mode,
proton and
neutron single-particle levels are calculated for representative fragments to examine their shell structures. The AS1 heavy fragment exhibits
proton gaps at $Z=50$ and 52 and
neutron gaps at $N=82$ and 84, whereas well-developed gaps appear at $Z=56$ and $N=88$ in the AS2 heavy fragment. The mass splits of AS1 and AS2 are close to those of the conventional Standard I and Standard II modes, respectively. However, the average total kinetic energy is lower for AS1 than for AS2, opposite to the conventional ordering of Standard I and Standard II. This reversal reflects the more elongated shape of the AS1 light fragment. The SL mode is conventionally interpreted in terms of macroscopic
liquid-drop effects, whereas the pronounced
proton shell gap at $Z=46$ suggests that
proton shell effects also contribute to the elongated symmetric configuration. The classification based on fragment mass and the quadrupole deformations of both fragments provides a basis for distinguishing fission modes and examining the corresponding fragment shell structures at scission.
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All authors K. Okada, K. Nishio, T. Wada, N. Carjan
Nuclear Theory
Fission Modes and Fragment Shell Structures in $^{258}$Md$^*$ from Six-Dimensional Langevin Calculations
K. Okada, K. Nishio, T. Wada et al. (+1 more)
The fission of $^{258}\mathrm{Md}^{*}$ is calculated in the excitation energy range of $E^{*} = 6$–$36$~MeV using a six-dimensional Langevin framework with the Cassini shape parametrization. The calculated events are classified into two symmetric and two asymmetric fission modes based on the fragment mass and the quadrupole deformations of the two fragments at scission. The symmetric modes are the short mode with high total kinetic energy (TKE) and the superlong mode with low TKE, whereas the asymmetric modes differ in mass asymmetry. With increasing excitation energy, the yield of the short mode decreases, whereas the combined yield of the two asymmetric modes increases, as observed in the in-beam
prompt-fission study of $^{258}\mathrm{Md}^{*}$. From an analysis of the fragment shapes and associated single-particle levels, the short mode and the dominant asymmetric mode with the smaller mass asymmetry are found to involve a compact fragment characterized by deformed shell gaps at $Z = 52$ and $N = 84$, while the complementary fragment is compact in the short mode and strongly elongated in the asymmetric mode.
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All authors K. Okada, K. Nishio, T. Wada, N. Carjan
Fluid Dynamics
Correlative effects of induced magnetic field-buoyancy on reactive solute dispersion dynamics in couple-stress fluids
Aritra Roy, Debabrata Das and Pranab Kumar Mondal
We investigate the dispersion of a reactive solute in a couple-stress fluid flowing between two parallel plates under the combined effects of pressure-driven flow, buoyancy, and an induced
magnetic field. The model incorporates first-order heterogeneous reactions at both channel walls alongside a bulk reaction. Using Mei's multiscale homogenization technique accurate to third order, we develop a higher-order asymptotic formulation to determine the effective longitudinal dispersion coefficient and concentration field. Analytical predictions are complemented by Brownian dynamics simulations and finite-difference solutions, while the Aris method of moments quantifies transient mean displacement, spatial variance, and effective dispersivity. The hydrodynamic analysis reveals a singular branch in the velocity solution when the Hartmann number equals half the couple-stress parameter and identifies a characteristic quarter-power scaling between the Hartmann number and couple-stress parameter, separating couple-stress- and magnetically dominated regimes. The model recovers classical Taylor-dispersion behavior in the non-reactive Newtonian limit and agrees well with experimental measurements. Couple-stress rheology and
magnetic damping suppress shear-induced dispersion, whereas buoyancy enhances dispersion through additional transverse velocity gradients. A distinct saturation regime of the dispersion coefficient emerges with an increasing couple-stress parameter, while unequal wall absorption induces persistent transverse asymmetry, and stronger absorption enhances solute removal near the source. Numerical and
stochastic results validate the analytical framework while resolving higher-order concentration structures and particle-scale wall adsorption.
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