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Physics

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Wednesday 2 September

Mesoscale and Nanoscale Physics

Room-temperature local strain control of moiré excitons in MoS$_2$/WSe$_2$ heterobilayers

T. O. Oskolkova, Y. Koo, A. A. Shubnic et al. (+8 more)

Moiré superlattices in heterobilayers of atomically thin transition metal dichalcogenides provide a versatile platform for exploring quantum many-body physics as they can trap excitons, leading to the formation of quantized moiré exciton states. However, such moiré excitons have been predominantly studied at cryogenic temperatures, which severely limits their practical applications. Here, we demonstrate room-temperature activation and control of moiré excitons in MoS$_2$/WSe$_2$ heterobilayers using local strain engineering. Applying mechanical strain with a modified atomic force microscopy tip, we observe a series of resonances attributed to interlayer exciton states confined in the moiré potential. Power-dependent photoluminescence measurements elucidate the population dynamics of the moiré exciton states, while controlled local strain enables continuous tuning of their emission wavelength to the center of the second telecom window. We provide a theoretical model that captures all experimentally observed features, including the unconventional spectral shape of the moiré exciton emission. Our findings establish local tip-induced strain as a powerful tool for the on-demand manipulation of moiré excitons, paving the way for room-temperature quantum excitonic devices.
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All authors T. O. Oskolkova, Y. Koo, A. A. Shubnic, I. Yu. Chestnov, I. Choi, C. Cheng, D. Huang, T. Jiang, K.-D. Park, I. V. Iorsh, V. Kravtsov

Mesoscale and Nanoscale Physics

In silico design of magnonic lasing in constricted waveguides

Jean F. Oliveira da Silva, Rai M. Menezes and Milorad V. Milosevic

Analogue black-hole systems have been proposed in various physical platforms, including magnetic materials, offering rich physics and promising applications such as wave lasing. However, their practical realization and characterization remain largely unexplored. Here, we present an in silico study of magnonic black-hole phenomena in constricted ferromagnetic waveguides driven by spin-polarized currents. Using micromagnetic simulations with a two-dimensional Poisson solver to obtain realistic current-density profiles, we demonstrate the formation of a double-hole cavity bounded by analogue event horizons, enabling resonant spin-wave amplification. We characterize the resonances as a function of magnetic and geometric parameters and identify the corresponding spin-wave modes. We further show that gradual tapers enhance transmission by suppressing spin-wave reflections, while interfacial Dzyaloshinskii-Moriya interaction can mimic the current-induced Doppler shift, substantially reducing the critical current density required for applications and, consequently, Joule heating. Finally, we demonstrate a spin-wave laser in which thermally excited spin waves undergo selective amplification and coherent emission at well-defined resonance frequencies. These results provide design principles for magnonic analogues of gravitational systems and point toward their potential for advanced spintronic applications.
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Instrumentation and Detectors

Toward High-Resolution Detection of Target Fragmentation: TEA-Sensitized NIT for Proton Therapy Applications

V. Boccia, T. Asada, A. Alexandrov et al. (+96 more)

Nano Imaging Trackers (NIT) are fine-grained nuclear emulsions capable of tracking charged particles with sub-micrometric spatial resolution. The DAMON (Direct Measurement of Target Fragmentation) experiment recently employed NIT to detect target-fragmentation events relevant to proton therapy in direct kinematics. These measurements showed that the small crystal size, while providing high spatial resolution, limits the reconstruction efficiency for primary proton tracks and high-energy secondary protons. This work reports an enhancement of NIT sensitivity achieved through alternative chemical sensitization methods, namely gold-plus-sulfur (Au-S) and triethanolamine (TEA), together with the use of the GR-1 developer. The detector response was evaluated with gamma-ray, carbon-ion and proton exposures, including clinically relevant proton energies.
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All authors V. Boccia, T. Asada, A. Alexandrov, G. Ambrosi, S. Argirò, M. Barbanera, N. Bartosik, G. Battistoni, A. Bigot, M. G. Bisogni, G. Butella, F. Cavanna, P. Cerello, E. Ciarrocchi, N. D'Ambrosio, G. De Lellis, A. Di Crescenzo, B. Di Ruzza, M. Dondi, M. Donetti, Y. Dong, M. Durante, R. Faccini, V. Ferrero, C. Finck, E. Fiorina, M. Francesconi, M. Franchini, G. Franciosini, L. Galli, A. Iuliano, K. Kanxheri, B. Kharpuse, M. Kimura, S. Kodaira, A. C. Kraan, A. Lauria, E. Lopez Torres, T. Maggipinto, M. Magi, A. Manna, M. Marafini, S. Masci, M. Massa, C. Massimi, I. Mattei, S. Mazzolani, A. Mengarelli, A. Mereghetti, R. Mirabelli, A. Moggi, M. C. Montesi, M. C. Morone, M. Morrocchi, S. Muraro, T. Naka, N. Pastrone, V. Patera, F. Pennazio, C. Pisanti, P. Placidi, M. Pullia, F. Quattrini, S. Rabaglia, L. Ramello, C. A. Reidel, R. Ridolfi, L. Rocchetti, L. Sabatini, L. Salvi, C. Sanelli, A. Sarti, O. Sato, S. Savazzi, A. Schiavi, C. Schuy, E. Scifoni, L. Servoli, G. Silvestre, M. Sitta, K. Someya, B. Spadavecchia, R. Spighi, E. Spiriti, L. Testa, V. Tioukov, S. Tomassini, F. Tommasino, M. Toppi, G. Traini, A. Trigilio, G. Ubaldi, S. Valentinetti, M. Vanstalle, M. Villa, U. Weber, R. Zarrella, A. Zoccoli, G. Galati

Optics

Dispersion-engineered meta-coverslip for multimodal synthetic imaging

Yuchen Ma, Danlin Xu, Xinwei Wang et al. (+2 more)

Multimodal optical imaging provides comprehensive sample characterization but has traditionally been hindered by complex and bulky instrumentation. Here, we propose a dispersion-engineered meta-coverslip to seamlessly integrate bright-field, differential, fluorescence, and holographic imaging modalities within a standard microscope architecture, requiring no hardware modification or realignment. The meta-coverslip utilizes a scalable subwavelength multilayer film to engineer spatio-temporal dispersion for a customized high-dimensional transfer function. As an example, we demonstrate flexible switching among the four imaging modalities by simply tuning the illumination wavelengths. Lastly, we demonstrate that the synthesis of multimodal images can provide spatially registered structural and molecular information for more comprehensive biological analysis. Our approach provides an accessible, scalable, and flexible solution for advanced imaging and is extensible to other multiplexed optical systems in sensing and computing.
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All authors Yuchen Ma, Danlin Xu, Xinwei Wang, Guangwei Hu, Liangcai Cao

Mathematical Physics · Cross-listed from math.PR

Metastability of interacting stochastic systems with countably many metastable states: beyond positive recurrence

Seonwoo Kim and Jungkyoung Lee

Metastability is typically formulated for systems with finitely many metastable states, most often in positively recurrent settings. In this article, we extend the resolvent framework for metastability to Markov processes with countably many metastable states, thereby encompassing null-recurrent and transient dynamics. For a family of processes on locally compact Polish spaces, we prove, under a mild boundary regularity assumption, that the asymptotic flatness of microscopic resolvent solutions, supplemented by two compactness conditions, is equivalent to convergence in law of the projected trace processes to a limiting Markov chain and to the negligibility of the time spent outside the metastable sets. We apply this framework to two non-compact stochastic systems. First, we study a condensing inclusion process on a countably infinite, uniformly locally finite graph, in a setting where the process may be null recurrent or transient. We prove that the condensate location converges to a weighted random walk on the underlying graph, while the time spent away from the fully condensed configurations is negligible. Second, we study a small-noise one-dimensional Langevin diffusion with countably many stable equilibria, without assuming ergodicity. In the Eyring-Kramers time scale associated with the minimal energy barrier, we establish local equilibration inside each well, convergence of the well-index process to an explicit nearest-neighbor Markov chain on $\mathbb Z$, and negligibility of inter-well excursions. Together, these results broaden the scope of resolvent-based metastability theory beyond finite metastable state spaces and positive recurrence.
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High Energy Physics (Theory)

QFT on flat, compact, orientable manifolds

Sebestyen Nagy and Daniel Nogradi

Motivated by the recent observation that rotating space-times at finite temperature can be described by particular flat, compact, orientable manifolds, which are different from $\mathbb T^4$, we catalogue all such 4-manifolds and their properties. There are in total 26 flat, compact, orientable 4-manifolds, 23 of them spin-manifolds, so fermions and a Dirac operator can also be defined on these. Seven of them are appropriate for finite volume periodic boxes undergoing rotation at finite temperature.
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High Energy Physics (Phenomenology)

Distribution amplitudes of vector and axial-vector mesons in a nonperturbatively improved symmetry-preserving framework

Zhen-Ni Xu, Zhao-Qian Yao, Peng Cheng et al. (+1 more)

Using continuum Schwinger-function methods with a nonperturbatively improved, symmetry-preserving kernel, we deliver predictions for the leading-twist light-front distribution amplitudes (DAs) of the $\rho$, $K^\ast$, $a_1(1260)$, $b_1(1235)$, and the unmixed strange partners of the $1^{++}$ and $1^{+-}$ axial-vector (AV) channels, reconstructed from Mellin moments of the associated Bethe–Salpeter wave functions. For vector mesons, polarisation barely affects longitudinal momentum sharing: the longitudinal and transverse DAs are nearly degenerate, and both narrower than the asymptotic distribution in the second-moment sense. The AV sector is different in kind. Charge conjugation compels one projection – interchanged between the $1^{++}$ and $1^{+-}$ channels – to vanish at $x=1/2$ and change sign; breaking $SU_F(3)$ symmetry removes this protection, whereupon the zeroth moments become nonzero and the nodes shift from the midpoint. Under a common weighted normalisation, the $1^{+-}$ zeroth moment is $1.63$ times that of the $1^{++}$ channel, and the profile distortion follows the same pattern. A coupling forbidden by charge conjugation in the symmetric limit, $f_{b_1}=0$, becomes $f_{K_1^{+-}}=0.019\,$GeV in the strange channel: an independent measure of the same symmetry breaking, obtained from a current matrix element rather than from the DA reconstruction. What distinguishes the two sectors is thus a symmetry-enforced zero, not the size of the flavour asymmetry.
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All authors Zhen-Ni Xu, Zhao-Qian Yao, Peng Cheng, Khépani Raya

Plasma Physics

Chirped-Pulse Forward Raman Amplification in Nonuniform Plasmas

Zhi-Yu Lei, Zheng-Ming Sheng, Su-Ming Weng et al. (+2 more)

Light amplification via Raman scattering in plasma has been severely constrained by stringent phase matching conditions and the need for plasma uniformity. To overcome these limitations, we propose a forward Raman amplification scheme that employs a positively chirped seed pulse co-propagating with a pump pulse in a nonuniform plasma with an upramp density profile. We demonstrate that the phase detuning induced by plasma nonuniformity can be dynamically compensated, enabling broadband amplification across the entire spectral bandwidth of the seed pulse. Concurrently, the chirped pulse duration undergoes continuous compression as a result of the spatially varying dispersion of the plasma. Our theoretical model, incorporating the detuning term and supported by particle-in-cell simulations, elucidates the compensation mechanism. It is shown that a chirped seed pulse with an initial bandwidth ~10% can be directly amplified by a factor of 1e7 to an intensity exceeding 1e17W/cm2 within a picosecond timescale in a steep density ramp. This scheme establishes a new foundation for advancing plasma-based light amplification toward practical applications.
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All authors Zhi-Yu Lei, Zheng-Ming Sheng, Su-Ming Weng, Min Chen, Jie Zhang

Mathematical Physics · Cross-listed from math.AP

A Payne-Weinberger inequality for quantum dot Dirac operators

Joaquim Duran, Albert Mas and Tomás Sanz-Perela

In this work we prove a Payne-Weinberger type inequality for quantum dot Dirac operators defined on bounded and simply connected planar domains. This is a sharp upper bound for their first positive eigenvalue depending only on the isoperimetric deficit of the domain. To this end, we use a recently studied connection with the so-called $\overline\partial$-Robin Laplacian and we establish an analogous inequality for its first eigenvalue, relying on the corresponding inequality for the Robin Laplacian.
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Materials Science

Ferroelastic domain switching by ultrafast photoinduced strain

Daniel G. Lourens, Maarten Kwaaitaal, Carl S. Davies et al. (+1 more)

The crystal lattice underpins the fundamental properties of condensed matter, with ferroic order emerging sensitively from atomic coordination. Manipulating the lattic therefore promises a direct way to switch ferroics between their states. Infrared excitation provides an efficient pathway to drive lattice motion and generate transient crystal deformations and strains. Ferroelastics constitute a uniquely direct platform for such control, their order parameter being strain itself. However, whether ultrafast laser-induced lattice distortions can switch ferroelastic order remains unknown. Here we use ultrafast pump-probe microscopy to demonstrate that a single high-amplitude infrared pulse induces strain within the first nanosecond, followed by ferroelastic domain switching several nanoseconds later. The spatial distribution follows that expected from the photoinduced strain field, while their temporal evolution is closely coupled to the strain dynamics. Our observations identify transient strain as the driving field for ferroelastic switching and suggest a general lattice-mediated pathway for controlling ferroic order using infrared light.
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All authors Daniel G. Lourens, Maarten Kwaaitaal, Carl S. Davies, Andrei Kirilyuk

Solar and Stellar Astrophysics

Surface brightness inhomogeneity on the helium-rich hot subdwarf in the X-ray binary HD 49798

C. Simon Jeffery and Gavin Ramsay

HD 49798 is an X-ray binary consisting of a hot helium-rich subdwarf primary and an accreting compact companion with an orbital period of 1.55 d. TESS observations of its optical light curve suggest short-period brightenings superimposed on a sinusoidal variation. The latter can be attributed to the tidal deformation of the primary, while frequency analysis of the additional variations shows up to eleven frequencies which form an harmonic series based on a period of 1.4 d, in excellent agreement with the stellar rotation period inferred independently from spectroscopy. These brightenings may be explained by a slowly changing and inhomogeneous temperature distribution across the surface of the hot subdwarf, such as might be associated with a magnetic field or with the presence of Rossby waves in the stellar envelope.
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General Relativity and Quantum Cosmology

Redshift Spectroscopy as a Probe of Regular Black Holes, Black Bounces, and Scalar-Hair Compact Objects

Ali Övgün, Reggie C. Pantig and Joel Saavedra

Motivated by [Phys. Rev. D. 107, 064019 (2023)], we develop a unified and model-independent framework for the spectroscopy of photon frequency shifts in generic static, spherically symmetric spacetimes. Working with a line element characterized by three arbitrary radial metric functions, we derive exact expressions for the conserved quantities of massive and massless probes, the conditions for circular timelike geodesics, the local-emission-angle-dependent photon impact parameter, and the corresponding local redshift and blueshift branches measured by distant static observers. The formalism is further extended to include the line-of-sight peculiar motion of the source and the local propagation of photons in a nonmagnetized cold plasma, thereby identifying the gravitational, orbital, and dispersive factors entering the frequency-shift signal under the stated assumptions. We also show that, in vacuum, the same geometric structures governing orbital spectroscopy determine the photon sphere and the shadow impact parameter whenever an external null critical orbit is present. To make the framework suitable for deformed compact-object models, we construct a perturbative expansion around Schwarzschild geometry up to second order in a dimensionless deformation parameter, obtaining explicit corrections to the orbital energy, angular momentum, emitter four-velocity, photon impact parameter, and the vacuum and plasma frequency shifts. We apply the formalism to regular black holes from nonlinear electrodynamics, the Simpson–Visser black-bounce spacetime, and the Fisher–Janis–Newman–Winicour–Wyman geometry. These examples show that the same local spectroscopic language can be used across regular-black-hole, black-bounce, wormhole, and scalar-supported horizonless sectors.
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High Energy Physics (Phenomenology)

Quark masses and mixing in the D_5 model under spontaneous CP violation

Dong-Ping Fu and Michihisa Takeuchi

It is known that CP violation occurs in flavor physics, and the CKM matrix is complex. We investigate the Yukawa sector of a four-Higgs model based on D_5 symmetry. To understand all possible sources of CP violation in the Yukawa sector, we systematically analyze the impact of all possible representation assignments of the left-handed and right-handed quark fields under the D_5 group. After imposing the conditions of non-block-diagonal CKM matrix and the absence of massless quarks, we find that the only viable representation consists of one D_5 doublet and one singlet. In this case, two distinct types of quark mass models emerge in the quark sector. For each model, we introduce the most general vacuum that allows spontaneous CP violation (SCPV) into the mass matrices. Due to the specific structure of the D_5 symmetry, the vacuum expectation values (vevs) satisfy particular relations such that, for both quark models, the up- and down-quark mass squared matrices (i.e., M_d M_d^\dagger and M_u M_u^\dagger) can be simultaneously block-diagonalized by the same unitary transformation, forcing the CKM matrix to be block-diagonal and thus yielding vanishing mixing angles and CP violation. This result rules out the possibility of explaining experimental observations within the D_5 4HDM under the SCPV framework.
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General Relativity and Quantum Cosmology

Boundary-Geometry-Driven Black Hole Formation in Vacuum

Dipanjan Dey, Puskar Mondal and Shing-Tung Yau

We identify a boundary-geometry-driven mechanism for the dynamical formation of marginally outer trapped surfaces (MOTSs) in vacuum general relativity. Mild three-dimensional anisotropies evolve inside a compact Cauchy domain whose effective isotropic thickness remains controlled, while the generalized boundary mean curvature can increase during either contracting or expanding boundary evolution. This drives the boundary across Yau's geometric threshold, forcing MOTS formation from initially untrapped data. We further interpret the characteristic shear construction of Ref.~\cite{MondalYau2026} as the null manifestation of the same anisotropic vacuum dynamics. The result provides a purely vacuum physical realization of MOTS formation through global geometric effects, without invoking a short-pulse concentration mechanism for gravitational radiation.
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Fluid Dynamics

Improved uncertainty representation for reducing artificial energy production in structured input-output stability analysis

Ofek Frank-Shapir and Igal Gluzman

This work employs a new form of fixed structured uncertainty within the structured small-gain theorem approach proposed by Frank-Shapir & Gluzman (J. Fluid Mech., vol. 1030, 2026, pp A8) for the stability analysis of incompressible shear flows subject to finite-magnitude disturbances. Within this framework, the nonlinear advection term in the Navier-Stokes equations is replaced by a structured feedback uncertainty interconnection with the linearized dynamics to account for the impact of nonlinear feedback. Herein, a new uncertainty representation is derived via linear transformations of the input and output channels, transforming the feedback loop such that the resulting structured uncertainty has a repeated-diagonal structure. This structure aims to preserve the component-wise pathways of the nonlinear advection term while keeping the structured singular value computation tractable. We apply the method to two canonical base flows: Couette and plane Poiseuille flows. The resulting thresholds on disturbance magnitude to preserve stability are less conservative and more accurate. We compare the novel methodology presented here with previously proposed repeated and non-repeated block approximations of the uncertainty structure, where our stability threshold provided the closest agreement with previous numerical and experimental studies. We show that repeated and non-repeated block structures that were proposed in past studies result in an artificial energy-production term arising from using constant structured uncertainty in the structured input-output formulation, violating the divergencefree assumption. This energy-production term is smallest when using the methodology presented in this work, providing a more faithful representation of the impact of nonlinear feedback interconnection with the linearized dynamics of the Navier-Stokes system.
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High Energy Physics (Theory)

Residues on Permanent Pinches: Finite Integrals and Leading Divergences

Dimitri Corradini, Cristian Vergu and Shun-Qing Zhang

We study infrared (IR) divergences from the point of view of permanent pinches. We show how canceling permanent pinches allows us to form finite linear combinations of integrals. We further show how to compute scheme-independent leading IR divergences with- out introducing a regulator, by integrating certain residue forms along desingularizations of permanent pinch varieties. Our methods work for massless and mixed massive-massless inte- grals, for non-planar integrals with arbitrary numerators as well as for integrals with higher (integer) powers of propagators. We use this analysis to determine leading singular terms in some examples of box integrals. We further study examples of finite integrals at higher loops, and in particular provide a basis for finite non-evanescent integrals in a non-planar two-loop five-point topology.
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Fluid Dynamics

Mechanism-Resolved Interface Momentum Transfer in Immersed-Boundary Lattice Boltzmann Simulations

Hongju Jo

Immersed-boundary lattice Boltzmann (IB-LBM) simulations of cylinder and particle flows are usually compared by ranking boundary-enforcement schemes, kernels, and collision models. Such comparisons can obscure the mechanism that controls each response. Here, canonical fixed-cylinder, oscillating-cylinder, and sedimenting-particle cases are used as controlled probes of Eulerian-Lagrangian interface momentum transfer. For prescribed bodies, differences among direct forcing (DF), multi-direct forcing (MDF), and distribution-function correction (DFC) are most clearly discriminated by local no-slip fidelity rather than by a universal drag ranking. For DFC, the kernel-dependent drag-coefficient ranking reversal between the hat and Peskin 4-point kernels is associated with the spatial redistribution of the marker-resolved correction and the resulting near-boundary slip and pressure deviation, rather than the total correction magnitude alone. For sedimenting particles, single-particle settling provides a moving-body baseline, whereas two-particle differential-density wake-interaction sedimentation shows the wake-exposed light particle to be comparatively more sensitive to the explicit internal-mass correction in the force evaluation, a configuration-dependent, finite-window moving-boundary closure response. Targeted two-relaxation-time (TRT) and central-moment multiple-relaxation-time (CM-MRT) collision controls remain secondary to the boundary and closure mechanisms within the tested regimes (prescribed-body comparisons at Re <= 200, two-dimensional, and the reported moving-particle cases). The resulting picture replaces a universal scheme ranking with a mechanism-resolved interpretation of IB-LBM interface momentum transfer.
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Mathematical Physics · Cross-listed from math.SP

Robin counting functions on cuboids in the critical scaling regime

Matthias Baur and Simon Larson

We consider eigenvalue counting functions of Robin Laplace operators on cuboids where the Robin parameter and the spectral cut-off $\lambda$ are coupled. Our main focus is the critical regime, in which the Robin parameter is proportional to $\sqrt{\lambda}$. We obtain a two-term asymptotic expansion for the counting functions in this coupled setting. In the critical regime, the second term in the asymptotic expansion depends non-trivially on the proportionality constant and interpolates continuously between the corresponding second terms for the Dirichlet and Neumann Laplacians. Outside the critical regime, one recovers the corresponding Dirichlet or Neumann asymptotics. We also establish a Pólya-type inequality for the counting function whenever the ratio of the Robin parameter and $\sqrt{\lambda}$ exceeds a dimension-dependent threshold.
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Superconductivity

Quantum Structural Renormalization and Anharmonic Stabilization of Superconductivity in P4/mmm YScH8

Xiaorui Dong, Mi Pang, Wenjie Ma et al. (+2 more)

The recent synthesis of P4/mmm-YScH$_{8}$ at 191.7 GPa with a superconducting critical temperature Tc of 113 K has attracted considerable interest in the study of ternary superhydrides. Here we systematically evaluate the effects of quantum and anharmonic motion of ions in P4/mmm-YScH$_{8}$ using the stochastic self-consistent harmonic approximation (SSCHA). We find that these effects renormalize the crystal structure and lower the dynamical stability threshold pressure from $\sim$140 GPa to $\sim$84 GPa, a reduction of about 40%. Furthermore, neglecting these effects causes a significant overestimation of the $T_{c}$, for instance by $\sim$20 K at 190 GPa. Our prediction of $T_{c}$ at 190 GPa is 113 K ($\mu^{*}$= 0.13), close to the experimental observation. Analysis of the phonon density of states and Eliashberg spectral function further reveals site-dependent contributions to superconductivity. These results establish that a consistent treatment of nuclear quantum motion and anharmonicity is essential for accurately predicting superconductivity in compressed ternary hydrides.
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All authors Xiaorui Dong, Mi Pang, Wenjie Ma, Yao Ma, Pugeng Hou

Materials Science

Vitrification-Devitrification Enables Tunable Photonic and Gas Sorption Properties of Zeolitic Imidazolate Frameworks

Zhencai Li, Zihao Wang, Minhyuk Kim et al. (+14 more)

Zeolitic imidazolate framework (ZIF) glasses represent an emerging family of melt-quenched glasses, which exhibit immense potential for applications in gas separation, energy storage, and optics. However, their intrinsic porosity remains elusive due to the inherent challenges in resolving their disordered atomistic structures. Here, we systematically investigate the porosity of ZIF-4 and ZIF-62 crystals and their corresponding glasses. CO2 sorption at 195 K enables quantitative assessment of microporosity in both crystalline and glassy states, allowing the accessible micropore volume of the ZIF glasses to be determined. Moreover, establishing a direct relationship between photonic properties and structural porosity in Zn-based ZIF glasses remains challenging. Here we demonstrate striking broadband blue-light emission from ZIF-4 glass annealed under optimized conditions. A pronounced red shift is observed when increasing the annealing temperature above the glass transition temperature. By correlating the evolution of photoluminescence with structural porosity, we reveal the interplay between the photonic and gas sorption properties of ZIF glasses. These findings provide new insights into the structure-property relationships of ZIF glasses and offer a pathway toward the rational design of multifunctional MOF glasses.
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All authors Zhencai Li, Zihao Wang, Minhyuk Kim, Huotian Zhang, Bozhao Yin, Yong Li, Qi Zhang, Fengming Cao, Xuan Ge, Laurent Calvez, Daniel Irving, Guoping Dong, Feng Gao, Haomiao Zhu, Morten M. Smedskjaer, Hoi R. Moon, Yuanzheng Yue

High Energy Physics (Phenomenology)

Evading Sudakov Dilution in Gluon Tomography

Shuo Lin and Jian Zhou

Sudakov broadening and competing azimuthal harmonics from final-state soft radiation limit the precision of gluon tomography. We suppress both effects using fiducial hadronic recoil—the vector sum of all hadronic transverse momenta within a rapidity interval—while a tagged jet fixes the azimuthal axis. Momentum conservation ensures that emissions inside the interval contribute neither to recoil broadening nor to these harmonics, so widening the interval reduces their impact without a soft-radiation veto. As a benchmark, we study the $\cos 2\phi$ modulation probing $h_1^{\perp g}$ in DIS. For rapidity interval $\Delta\eta=3$, fiducial recoil enhances the $h_1^{\perp g}$ contribution by a factor of $4.6$ and suppresses the final-state soft gluon term by a factor of $4.0$ relative to the conventional dijet imbalance. Fiducial recoil thereby enables precision gluon-TMD tomography.
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Fluid Dynamics

Ventilated Cavitation around a sphere through surface air injection at Re = 10,000

Soundararajan R and Anikesh Pal

We perform DNS of ventilated cavitation over a sphere at subcritical (Re=10,000). The flow is modeled as a homogeneous mixture of water and air, with the interface tracked using the volume-of-fluid method. Unlike previous numerical investigations, surface tension is explicitly included. Air is injected through a circular strip on the sphere at three locations selected based on the bulk flow dynamics: front (FR025, (18^\circ\leq\theta\leq63^\circ)), mid (MD025, MD050, (75^\circ\leq\theta\leq104^\circ)), and back (BK025, (120^\circ\leq\theta\leq180^\circ)), with (C_q=0.2) and (0.4). The injection location strongly governs cavity inception and stability and alters flow separation in the front- and mid-injection cases. Front injection produces an unsteady bubbly cavity due to vigorous puffing, which fragments the injected air and increases drag by (\sim56%) relative to the single-phase case. In contrast, mid- and back-injection produce stable cavities with distinct leading-edge dynamics. In the mid-injection cases, puffing dominates and, despite delayed flow separation, the cavity detaches from the leading edge of the injection patch. For back injection, the cavity detaches upstream of the injection patch owing to the adverse pressure gradient induced by cavity formation. Kelvin–Helmholtz instabilities and divot formation characterize the back-injection cavity. Stable cavities exhibit strong air entrainment and close through a re-entrant jet. The mid-injection cases achieve (35%) and (25%) drag reduction at (C_q=0.2) and (0.4), respectively, while back injection yields a maximum drag reduction of (46%) relative to the single-phase case.
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Mathematical Physics

Heat transfer problem of a dense gas described by the Enskog equation with a modification of the Enskog factor

Shigeru Takata, Soma Sakata and Masanari Hattori

Heat transfer in a dense gas between two parallel plates is studied for assessing the quantitative difference of two variants of the Enskog equation, i.e., the original Enskog equation and the Enskog equation with a modified Enskog factor recently proposed in Phys. Rev. E 111, 065108 (2025). The main advantage of the latter is that the H theorem, which the former lacks, has been established. The influence of the modification is assessed by comparing the macroscopic quantities in detail. It is found that the impact of this modification is quite limited and the two variants reasonably agree as a whole.
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Earth and Planetary Astrophysics

The NC-CC dichotomy in ruthenium isotopes: Implications for the origin of the late veneer

Jonas Pape, Emily A. Worsham and Thorsten Kleine

High-precision mass-independent Ru isotope data for iron meteorites reveal that in three-isotope diagrams including the p-process Ru nuclides 96Ru or 98Ru, non-carbonaceous (NC) meteorites plot along an s-process mixing line, while the carbonaceous (CC) type irons plot as a cluster off the NC-line. As previously observed for Mo, this offset can be accounted for by an r-process excess in CC over NC materials. As a highly siderophile element, Ru in the bulk silicate Earth (BSE) is thought to predominantly derive from the late veneer, making the Ru isotope dichotomy a powerful genetic tracer of Earth's late accretionary epoch. The BSE and the isotopically anomalous Itsaq Gneiss Complex as defined in prior studies plot on the NC-line defined in this study, suggesting a predominantly NC late veneer that may have evolved over time from more s-process-enriched to more s-process-depleted compositions. However, more precise 96Ru and 98Ru measurements of the BSE's composition are needed to more reliably determine the genetic heritage of the late veneer and to quantify as to whether it contains CC material.
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Superconductivity

Anomalous Superfluid Response in Altermagnetic Superconductors

Christian Wiedemann, Danilo Nikolić, Matthias Eschrig et al. (+1 more)

We report on the emergence of the anomalous (paramagnetic) superfluid response in altermagnetic superconductors at arbitrary impurity concentrations. Due to anisotropic gapless superconductivity, altermagnetic superconductors with an out-of-plane Zeeman field display an anisotropic paramagnetic Meissner effect. The effect is strongest for parallel altermagnetic and Zeeman exchange field vectors and in the clean sample. The presence of nonmagnetic impurities leads to isotropisation and, consequently, weakens the effect; however, the paramagnetic response sustains intermediate amounts of impurities in the system. As demonstrated in recent experiments, microwave superfluid stiffness measurements can serve as a sensitive probe of gapless superconductivity.
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All authors Christian Wiedemann, Danilo Nikolić, Matthias Eschrig, Wolfgang Belzig

Superconductivity

Vortex-core Majorana coupling to a chiral edge in a $p_x+ip_y$ superconductor: Nonmonotonic spectral reorganization and coherent fermion-parity dynamics

Peiyao Liu and Yi Zhou

We study how vortex–edge coupling reorganizes the low-energy sector of a finite two-dimensional \(p_x+ip_y\) superconducting disk as a function of the vortex–boundary separation \(d\) and examine what this reorganization implies for the parity memory associated with a prescribed vortex-core Majorana wave packet, a resource relevant to Majorana-based quantum operations. Bogoliubov–de Gennes calculations reveal nonmonotonic core–edge reorganization of the lowest positive-energy finite-disk eigenstate, with particularly rapid variation near \(d\simeq7\xi\), where \(\xi\) is the coherence length. To separate this eigenstate reorganization from the spectral representation of a prescribed state, we rigidly translate a centered-vortex core-reference packet to each fixed vortex position, restrict it to the target disk, and project it, without intermediate normalization, onto the particle-hole-complete low-energy subspace. For \(\Delta_0/E_F=0.36\) and disk radius \(R=30\xi\), the resulting retained norm exceeds \(0.98\) at all six sampled separations, \(4.25\leq d/\xi\leq8.25\), while, depending on \(d\), the spectral measure is concentrated near zero energy, fragmented over several low-energy levels, or dominated by finite-energy weight. Correspondingly, the signed parity correlator displays slow temporal variation, rapid coherent dephasing, or sign-changing oscillations, with possible finite-size recurrences at later times. Thus a large retained norm does not by itself imply spectral concentration or persistent parity memory.
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Materials Science

Linker Functionalization and pH Tuning Enhance Solar-Driven Catalytic CO$_2$ Reduction in MOF-5

Julia Santana-Andreo, Joshua Edzards, Surender Kumar et al. (+1 more)

The wide band gap of metal-organic framework (MOF) 5 constrains its use in photocatalytic carbon dioxide (CO$_2$) reduction despite its high porosity and favorable mass-transport properties. Adopting a state-of-the-art first-principles approach, we systematically investigate the effects of volumetric strain, metal-node substitution, linker functionalization, and pH control as knobs to improve the CO$_2$ photocatalytic ability of MOF-5. Strain and metal-node substitution negligibly affect the gap, whereas linker functionalization narrows it into the visible range via in-gap states while preserving reduction-side alignment at pH = 0. The resulting reduction energetics are strongly sensitive to both linker functionalization and pH. Halogenated and hydroxylated frameworks provide access primarily to HCOOH, CO, and HCHO under alkaline conditions, principally with the Mg and Zn nodes, whereas COOH functionalization offers the broadest thermodynamic accessibility across the full CO$_2$ reduction sequence. NH$_2$ retains thermodynamic feasibility for all target reduction pathways but with larger overpotentials, while NO$_2$ generally yields unfavorable reduction energetics. Crucially, within the COOH series, the choice of the metal node tunes the fundamental gap by over 1 eV with only minor changes in the reduction overpotentials, placing Sr- and Ba-based architectures as the most favorable ones for broad product selectivity with visible-light excitation. Linker functionalization substantially reduces the spatial overlap of the frontier states, promoting photoinduced charge separation. Taken together, these results establish linker functionalization and solution pH as complementary design levers for independently tuning light absorption and CO$_2$-reduction energetics in MOF-5, establishing a rational and viable route for designing efficient MOF-based photocatalysts.
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All authors Julia Santana-Andreo, Joshua Edzards, Surender Kumar, Caterina Cocchi

Instrumentation and Methods for Astrophysics

Searching for Gravitational Wave Events Counterparts in X-Rays by Tilting the Multiple Shells of Wolter-I Optics

John Rankin, Daniele Spiga, Paolo Conconi et al. (+5 more)

Current X-ray telescopes have a combination of field of view and angular resolution that makes it difficult to quickly localize the electromagnetic counterparts of gravitational wave events — which will become increasingly important when the LIGO and Virgo experiment will work at full sensitivity or when the Einstein Telescope and the Cosmic Explorer observatories will come online in the next decades. We investigate what X-ray optical designs could provide — in a small mission — a field of view wide enough to observe quickly the region of the sky constrained by gravitational wave detectors, and at the same time an angular resolution sufficiently good to localize these sources. We study, using ray tracing simulations, how we can optimize a Wolter-I telescope for this purpose. We find that, by appropriately tilting the shells of a Wolter-I X-ray telescope in different directions, the field of view increases, at the cost of a reduction of the on-axis performance. We draw a possible design made of two identical modules pointing at adjacent regions of the sky.
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All authors John Rankin, Daniele Spiga, Paolo Conconi, Sergio Campana, Giovanni Pareschi, Stefano Basso, Marta Maria Civitani, Vincenzo Cotroneo

Astrophysics of Galaxies

An updated census of the Vast Polar Structure member galaxies

Alberto Manuel Martínez-García

The Vast Polar Structure (VPOS) is a thin, planar arrangement of dwarf galaxies oriented almost perpendicular to the Milky Way (MW) disc. Since its discovery, the census of VPOS member galaxies has progressively expanded thanks to continuous findings of new dwarfs in the vicinity of the MW and increasingly precise measurements of their phase-space coordinates. In this work, we present the largest census to date of VPOS member galaxies, building on a sample of 73 MW dwarfs for which positional and kinematic data are available in the literature. Based on their orbital poles, we identify 22 VPOS members. We note that the majority of VPOS member galaxies are co-rotating, while only three systems are counter-rotating (Bootes III, Kim 1, and Sculptor). Our revised census increases the known VPOS member population by nearly 50%, introducing Delve 4, Kim 1, Kim 3, Eridanus III, Pictor II, and YMCA-1 as new on-plane dwarfs. From this updated census, we revise the structural parameters of the VPOS, confirming its planar ($c/a =0.27$) and remarkably thin (15 kpc) nature.
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Plasma Physics

Instabilities in Cylindrical Geometry Using the Minimalist Approach: Formalism and Rotational Instabilities

Nektarios Vlahakis

The minimalist approach for linear stability analysis is applied to fluids and magnetized ideal plasmas in cylindrical geometry. In this approach, the dispersion relation is obtained by integrating a single first-order differential equation - referred to as the principal equation - subject to appropriate boundary conditions. We first derive the principal equation for a general unperturbed state with radially varying density and pressure, axial and azimuthal components of both the velocity and magnetic field, and a radially directed gravitational field. We then use this formulation to analyze rotating flows with axial magnetic fields, addressing both wall-bounded and interface-driven axisymmetric instabilities. In addition to exact results for selected unperturbed states, we obtain approximate dispersion relations using the WKBJ method in the incompressible and compressible limits. The analysis encompasses centrifugal, magnetorotational, and buoyancy-driven instabilities as special cases, and it clarifies how compressibility modifies their stability properties.
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