Nuclear Experiment
Energy-energy correlators in p-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV
ALICE Collaboration
This paper presents the first measurement of the two-point energy-energy correlator (EEC) inside charged-particle jets in p-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV with the ALICE experiment. The two-point EEC, an infrared- and collinear-safe measure of angular energy flow within jets, is used to probe both perturbative and non-perturbative stages of the jet
evolution. The EEC is reported in 20-80 GeV/$c$ jets in p-Pb collisions and compared to a measurement of the EEC in pp events at $\sqrt{s} = 5.02$ TeV. A modification is observed in the 20-40 GeV/$c$ interval, with an enhancement at large opening angles and a suppression at small angles relative to pp collisions. The dependence of this modification on jet transverse momentum, rapidity, and forward activity is investigated. These results provide new constraints on cold
nuclear matter effects relevant for disentangling initial- and final-state contributions to jet-structure modifications. An understanding of these cold
nuclear matter effects is also relevant for interpreting EEC measurements in heavy-ion collisions.
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Computational Physics
Singular Vector Finite Element Basis Functions for Tetrahedra in Complex Electromagnetic Geometries
Samuel T. Elkin, Ghazi Khan, Ebrahim Forati et al. (+4 more)
Electromagnetic finite element method (FEM) implementations using traditional basis functions struggle to accurately represent field behavior near singular features such as conducting wedges. To combat this, specialized singular basis functions have been introduced to directly model the singular fields in these regions, leading to substantially improved performance. While these efforts have been pursued extensively in 2D, few functions have been developed for 3D elements. In this work, we develop basis functions for this in tetrahedra. Unlike prior functions, these basis functions are additive, meaning they are included alongside the standard vector basis functions to achieve more robust performance. Further, these functions are designed to be adaptable to tetrahedra touching several unique singular features by using combinations of basis functions singular with respect to each node and edge in the element, making them applicable to highly complex geometries. Higher-order interpolatory versions of the basis functions for modeling singular behavior with greater accuracy are also provided. These basis functions lead to substantial improvements in accuracy relative to the standard basis functions, and allow otherwise expensive simulations to be performed at far lower costs. As an application example, we perform simulations to extract critical quantities for designing superconducting
qubits that significantly depend on the behavior of singular fields. In Ansys HFSS, this took 21.27 hours and a peak
memory usage of 6.23 TB with 800 processors available, while using our singular basis functions achieved comparable results in 196 seconds while using 27.24 GB of
memory and only 16 processors. Due to these benefits, our singular basis functions could be applied to enable design optimization of electromagnetic geometries with dominantly singular behavior, such as superconducting
qubits.
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All authors Samuel T. Elkin, Ghazi Khan, Ebrahim Forati, Brandon W. Langley, Dogan Timucin, Reza Molavi, Thomas E. Roth
Quantum Physics
Stochastic signal sensing with finite energy and dead time at the fundamental quantum limit
James W. Gardner, Tuvia Gefen and Matteo Fadel
State preparation, measurement, and reset operations take finite time and use finite energy in realistic experiments, yet the impact of this on optimal
quantum metrological protocols is not properly understood. We study the effect on sensing a
stochastic signal, relevant for the detection of ultralight dark matter and other searches for fundamental physics. We prove that two-mode squeezed
vacuum is the optimal probe state given a finite mean-energy constraint for a family of incoherent sensing problems, including noise sensing and
quantum illumination. For estimating a gain independent of a loss, we show that
entanglement is a required resource to achieve the fundamental
quantum limit and observe a non-Gaussian to Gaussian transition in the optimal unentangled state as the dead time increases. We apply our results to bulk acoustic wave resonators.
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Materials Science
Chao Chen Ye, Gábor Kalla, Jianting Ye et al. (+1 more)
Quantum spin Hall insulators (QSH) are topological materials that host helical edge states protected against backscattering, making them ideal candidates for dissipationless
spin transport. Within the conventional $\mathbb{Z}_2$ classification, only phases with an odd number of edge state pairs ($\mathbb{Z}_2 = 1$) are topologically nontrivial, whereas even-channel systems ($\mathbb{Z}_2 = 0$) lie beyond this framework but can host robust edge transport characterized by a
spin Chern number. Experimentally accessible realizations of such phases remain rare, particularly in systems with sizeable band gaps. Here, we show that
bilayer ZrTe$_5$ realizes a double
quantum spin Hall phase in its energetically most stable structure. Using first principles calculations, we demonstrate that uniaxial strain drives a transition from this phase to a conventional single pair QSH phase with $\mathbb{Z}_2 = 1$. The double QSH phase hosts two pairs of helical edge states, resulting in enhanced edge conductance and a quantized
spin Hall response that remains robust over an energy window of up to $\sim$100 meV. These results establish
bilayer ZrTe$_5$ as a tunable platform connecting conventional and double QSH phases within a single material. More broadly, they demonstrate that untwisted van der Waals
bilayers can host topological phases beyond the conventional $\mathbb{Z}_2$ classification.
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All authors Chao Chen Ye, Gábor Kalla, Jianting Ye, Jagoda Sławińska
General Relativity and Quantum Cosmology
The free boundary problem in general relativity
Kostas Tzanavaris, Latham Boyle and Neil Turok
We study the action principle for space-times whose boundary is singular. We suggest that it is natural to treat the singularity as a free boundary, where the variation is unconstrained. Demanding that the action is stationary under such free variations then implies certain (on-shell) boundary conditions at the singularity. We derive these boundary conditions for the case of Einstein
gravity coupled to matter and show that, when applied to an initial spacelike singularity, they exclude Kasner-like or BKL space-times, but admit conformally regular space-times (including FLRW models) sourced by fluids satisfying $0 \leq P < \rho$. For standard hot big bang FLRW cosmologies, the admissible linear (scalar, vector, tensor) perturbations satisfy reflecting boundary conditions at the bang, in agreement with large-scale cosmological observations.
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High Energy Astrophysical Phenomena
Detailed Timing, Spectral, and Polarimetric Analysis of Magnetar 1RXS J170849.0-400910
Rachael Stewart, George Younes, Alice Harding et al. (+5 more)
We present a broadband timing, spectral, and polarimetric study of the magnetar 1RXS~J170849.0-400910 using XMM-Newton, NuSTAR, and IXPE. The pulse morphology evolves strongly across 0.5-70 keV. Below 3 keV, the emission is dominated by a broad soft pulse with a leading shoulder that develops into a faint interpulse near 3 keV, while the pulse fraction remains $\approx$25%. The profile becomes increasingly double-peaked between 3 and 20 keV and returns to a single peak at higher energies. The pulse fraction dips to $\sim$20% near 4 keV and rises to $\sim$42% above 25 keV. The phase-averaged spectrum is well described by an absorbed blackbody plus two power-laws, with $kT=0.468\pm0.003$ keV, $\Gamma_{\rm soft}=2.63\pm0.04$, and $\Gamma_{\rm hard}=0.5\pm0.1$. Phase-resolved spectroscopy reveals distinct soft and hard pulse components. The thermal modulation is driven primarily by a factor of $\sim$5 variation in projected emitting area, whereas the soft power-law exhibits two peaks with different phase and energy
evolution, suggesting distinct emission regions or mechanisms. The 10-70 keV flux is strongly anticorrelated with the soft power-law
photon index, linking spectral hardening to the hard pulse. The polarization degree also varies strongly with phase and energy. In the 2-3 keV band, it is anticorrelated with the intensity profile, consistent with magnetized-atmosphere emission, whereas in the 4-8 keV band it reaches $64\pm10$% during the nonthermal power-law-dominated peak. This high polarization can be reproduced by magnetospheric
quantum pair-synchrotron emission. Together, these results reveal an intricate, phase-dependent superposition of emitting regions and radiative processes whose complexity emerges only through broadband, phase-resolved spectropolarimetry.
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All authors Rachael Stewart, George Younes, Alice Harding, Hoa Dinh Thi, Matthew Baring, Zorawar Wadiasingh, Michela Negro, Alex Van Kooten
Statistical Mechanics
Making complex CFTs real: The two-dimensional Potts model for $Q>4$ and complex $Q$
Jesper Lykke Jacobsen and Kay Joerg Wiese
The two-dimensional $Q$-state Potts model with real couplings has a first-order transition for $Q>4$. Starting from a triangular-
lattice Potts model with two- and three-
spin interactions, we study an equivalent loop model in which $Q$ is a continuous parameter. By a combination of analytical and numerical arguments, we show that this loop model allows for the collision of a critical and a tricritical fixed point at $Q=4$. These then emerge as a pair of complex conformally invariant theories at $Q>4$, or even complex $Q$, for suitable complex coupling constants. We
conjecture that all conformal data (such as the central charge, critical exponents, and three-point structure constants) can be obtained by analytic continuation of known exact results for the loop model with $Q \le 4$. This
conjecture is checked, both for real $Q>4$ and for $Q \in \mathbb{C}$, by extensive transfer-
matrix computations and comparison to previous studies for $Q=5$.
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Instrumentation and Methods for Astrophysics
Querying an astronomical database using large language models: the ALeRCE text-to-SQL system
P.A. Estevez, J.Espejo-Moreira, S. Sanfeliu-Alvarez et al. (+10 more)
We develop a text-to-SQL (structured query
language) system based on large
language models (LLMs) using in-context learning and apply it to the Automatic Learning for the Rapid Classification of Events (ALeRCE) astronomical database. ALeRCE is a community broker for the Zwicky Transient Facility and the Vera C. Rubin Observatory. The system enables users to query the database in natural
language (NL) and generates executable SQL queries. To develop and evaluate the system, we constructed a
dataset of 110 NL/SQL pairs. We propose a step-by-step generation framework comprising four modules: schema linking, query classification,
prompt decomposition, and self-correction. The performance of thirteen LLMs is evaluated using in-context learning and
prompt engineering techniques. Text-to-SQL performance is assessed using the perfect-match (PM) rate for row identifiers (e.g., object identifiers) and column identifiers (i.e., column names). The proposed step-by-step framework consistently outperforms a direct-inference baseline, while the self-correction module consistently reduces execution errors. For Claude Opus 4.6, PM performance on row (column) identifiers is high for simple queries, reaching 0.97 (0.94), and decreases with query complexity to 0.44 (0.72) for medium queries and 0.59 (0.49) for hard queries. Among the thirteen evaluated models, the best-performing LLMs for the text-to-SQL task are Claude Opus 4.6, Gemini 2.5 Pro, Gemini 3 Flash, and GPT-5.2-Codex.
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All authors P.A. Estevez, J.Espejo-Moreira, S. Sanfeliu-Alvarez, F. Forster, A. M. Munoz Arancibia, G. Cabrera-Vives, F. E. Bauer, A. Bayo, M. Catelan, R. Dastidar, L. Hernandez-Garcia, J.A. Intriago, G. Pignata
High Energy Astrophysical Phenomena
Polarized emission of orbiting hot-spots near Sagittarius A*: effects of electromagnetic interaction
Abylaikhan Tlemissov, Arman Tursunov and Maciek Wielgus
We investigate the polarimetric signatures of orbiting hot-spots around a Schwarzschild black hole in the presence of an external
magnetic field, accounting for the electromagnetic interaction between the charged emitter and the field. Using a general-relativistic model that incorporates synchrotron emission and ray-tracing of light propagation, we analyze how the electromagnetic interaction parameter modifies the observed polarization patterns, with particular emphasis on the behavior of the electric vector position angle (EVPA) and the time-evolving polarization loops in the $Q$-$U$ plane. Applying the model to millimeter wavelength ALMA observations of Sagittarius~A*, we explore the parameter space that best reproduces the asymmetry, time ratio, and area ratio of the observed polarization loops. We find that the inclusion of a small positive interaction parameter increases the
symmetry of the loops and the time ratio, while a negative
magnetic parameter introduces strong asymmetry and fails to reproduce the data. Our results indicate that electromagnetic interaction can lead to ambiguity in the estimation of the system parameters such as orbital inclination or hot-spot velocity.
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Astrophysics of Galaxies
The ultra-deep HI radial profiles of late-type galaxies from MHONGOOSE
S. Veronese, W. J. G. de Blok, E. Brinks et al. (+4 more)
Galaxy discs have a finite extent, yet how and where their neutral atomic hydrogen (HI) components end is not fully understood. The existence of a break in the HI disc at column densities of $\sim10^{19}$ cm$^{-2}$ has been debated since early 21-cm observations of the spiral
galaxy NGC 3198. We present the HI radial profiles of 16
star-forming, late-type
galaxies from the MeerKAT HI Observations of Nearby
Galactic Objects: Observing Southern Emitters (MHONGOOSE) survey spanning a range of HI mass from $10^{7}$ M$_\odot$ to $10^{10}$ M$_\odot$. We probed via spectral stacking their HI discs down to inclination-corrected column densities of a few times $10^{17}$ cm$^{-2}$ at kpc resolution. The HI radial profiles of high-mass (M$_{\rm {HI}}>10^{9}$ M$_\odot$)
galaxies are characterised by a inner plateau, followed by a knee at column densities of $\sim5\times10^{20}$ cm$^{-2}$, but no edges are unambiguously identified. The HI radial profiles of low-mass (M$_{\rm {HI}}>10^{9}$ M$_\odot$)
galaxies shows a steeper decline and also no edges. We found that the profiles are self-similar when normalised to the radius at which a mass surface density of 0.01 M$_\odot$ pc$^{-2}$ is reached, in agreement with recent literature results, but we also found a possible correlation between the normalisation radius and the environment, suggesting that environment contributes to the shaping of the HI distribution in
galaxies. The emerging picture is that the diverse morphology of the HI radial profiles is difficult to interpret, and future studies with a larger sample are necessary for quantifying the contribution of internal and external processes acting at different levels for different
galaxies.
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All authors S. Veronese, W. J. G. de Blok, E. Brinks, D. Kleiner, S. Kurapati, J. Healy, F. M. Maccagni
Earth and Planetary Astrophysics
Effect of tidal gravity and planetary rotation on the retrieved atmospheric abundances of close-in exoplanets
K. Arnav and Gopal Hazra
Most modern atmospheric
retrievals adopt the simplifying assumption that the planetary atmosphere endures no planetary rotation and
stellar tidal effect. However, for tidally locked close-in
exoplanets, the gravitational influence of the host
star and the rapid rotation of the
planet can significantly modify the effective
gravity, leading to changes in the atmospheric scale height and mixing ratios of molecular abundances. In this work, we develop a combined framework to include these rotation and
tidal effects into a forward and
retrieval model to study how they affect the molecular abundances of close-in
exoplanets. We specifically apply our model to the
planet WASP-12b, observed with HST, and WASP-121b, observed with JWST, and investigate how atmospheric
retrieval parameters change when
tidal and centrifugal corrections to
gravity are included. The forward model calculation for strongly affected
gravity in WASP-12b shows an increment in transit depth in the range of 300-600 ppm for major molecules, whereas for WASP-121b with relatively less
gravity reduction shows variations of 60-140 ppm. The atmospheric
retrievals for both
planets with and without effective
gravity corrections show differences in the retrieved molecular abundances. To validate the detectability of these
gravity-induced changes, we perform synthetic injection-recovery experiments over a broad wavelength range, which show statistically significant shifts in the retrieved atmospheric parameters for simple atmospheric compositions, while more complex atmospheric compositions exhibit smaller changes due to increased
retrieval degeneracies. Finally, we investigate the robustness of these results using non-isothermal P-T profiles and cloudy atmospheric models, and find that the inferred trends remain qualitatively consistent.
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Cosmology and Nongalactic Astrophysics
Large primordial non-Gaussianity from transient turns in Higgs-$R^2$ inflation
Flavio Pineda and Luis O. Pimentel
We investigate the generation of
primordial non-Gaussianities in multifield
Higgs–$R^2$ inflation, focusing on the effects of transient turning trajectories in the
hyperbolic field space
manifold. We compute the full bispectrum without relying on slow-roll or local approximations and follow the complete superhorizon
evolution of
curvature and isocurvature perturbations. We show that transient turns efficiently transfer isocurvature fluctuations into the adiabatic sector, generating sizeable local non-Gaussianities. For a
benchmark Higgs nonminimal coupling $\xi_h = 0.1$ and quartic coupling $\lambda = 10^{-10}$, we obtain $f_{\rm NL}^{\rm loc}\simeq -17.7$. As the
Higgs nonminimal coupling increases, the turning rate is progressively suppressed and the model approaches the effective single-field attractor, recovering the Maldacena consistency relation $f_{\rm NL}\rightarrow 0.0159$. Comparing our predictions with current CMB constraints, we find that
primordial non-Gaussianity provides a sensitive probe of the
Higgs nonminimal coupling and can significantly restrict the viable parameter space of the model.
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Nuclear Experiment
Probing jet evolution with charged energy correlators in small systems
ALICE Collaboration
The ALICE Collaboration presents measurements of charged energy-energy correlators (charged EECs) within charged-particle jets at $\sqrt{s_{\rm NN}} = 5.02$ Tev in
proton-
proton and
proton-lead collisions at the LHC. Charged EECs are a class of jet substructure observables that trace the flow of energy and electric charge within a jet, and provide a tool for disentangling the energy scales involved in the jet fragmentation process through the angular separation and charges of particle pairs. The interplay between energy distribution and charge conservation enables charged EECs to provide novel constraints on hadronization mechanisms. Measurements of charged EECs in
proton–
proton collisions in charged-particle jets with $20 < p_{\rm T,chjet} < 80$ GeV/$c$ are compared to event generators to investigate different hadronization mechanisms and parton shower models. These model comparisons show that the like-sign EECs are sensitive to changes in parton shower modeling, while unlike-sign EECs are sensitive to different hadronization schemes. Measurements in
proton-lead collisions indicate that cold
nuclear matter effects on charged EECs are consistent with charge-independent behavior.
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Quantum Physics
Quantum statistical enhancement of collective behaviour in a bosonic active Ising model
Kian L. Assent, Emil Strauch, Sabine H. L. Klapp et al. (+2 more)
Collective behaviour such as flocking (the collective motion of a spontaneously formed group along a common direction) or aster formation (the binding of opposing flocks, inhibiting each others motion) are intriguing emergent phenomena in active systems with local
alignment rules. Until recently, their occurrence was mainly studied for classical systems, a
prime example being the active Ising model (AIM), which translates the main ingredients of flocking and aster formation (i.e.,
alignment and self-propulsion) to a
lattice framework. Here we introduce and study a one-dimensional (1D)
quantum lattice variant of the AIM, based on ideal
bosons with a
spin degree of freedom. We find that both the collective behaviours of the 1D classical model, flocking and aster formation, are markedly enhanced by the bosonic
quantum statistics. This contrasts with a recent
quantum generalization of the AIM based onto hard-core
bosons [Khasseh et al., Phys. Rev. Lett. 135, 248302 (2025)], where flocking, but neither its
quantum-statistical stabilization nor aster states were observed as a consequence of interactions. Moreover, we investigate the competition of this
quantum statistical stabilization of collective phases with their suppression by the
quantum fluctuations induced by a transverse external
magnetic field.
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All authors Kian L. Assent, Emil Strauch, Sabine H. L. Klapp, André Eckardt, Alexander Schnell
Materials Science
Impact of dynamic electrostatic disorder on hole mobility in rubrene: a nonadiabatic molecular dynamics investigation
Jan Elsner, Samuele Giannini and Jochen Blumberger
High-mobility organic molecular
crystals such as rubrene are important materials for organic electronics, yet a quantitatively predictive description of their charge transport properties remains challenging. Direct mixed
quantum-classical nonadiabatic molecular dynamics simulations provide a promising route by explicitly propagating the charge carrier wavefunction, without assuming a specific transport mechanism. However, previous large-scale simulations of apolar molecular
crystals have commonly neglected dynamic electrostatic disorder, since evaluation of electrostatic interactions is computationally demanding and the approximation appears plausible for apolar systems. Here, we use the damped shifted-force (DSF) real-space electrostatic summation method, combined with an efficient addition-subtraction scheme, to include dynamic electrostatic disorder in fragment orbital-based surface hopping (FOB-SH) simulations of room-temperature hole transport in rubrene. We find that electrostatic interactions increase the reorganization energy for (hypothetical) nearest neighbour hopping by 29 and 39 meV along the a and b-directions, respectively, relative to a baseline value of 152 meV obtained without electrostatics. In FOB-SH simulations, electrostatic interactions lead to increased site energy disorder, reducing the spatial extent of the hole wavefunction, as measured by a decrease in the inverse participation ratio from 13 to 9, and lowering the predicted mobility along the high-mobility direction from $35$ to $21~\mathrm{cm^2 V^{-1}s^{-1}}$, in close agreement with experiment.
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High Energy Physics (Phenomenology)
Ultra-High-Energy Cosmic Ray Boosted Relic Neutrinos
Jiajie Zhang and Jiajun Liao
Ultra-high-energy
cosmic rays (UHECRs) can boost relic
neutrinos to high energies through Standard Model (SM) neutral-current interactions, providing an indirect probe of the
cosmic neutrino background (C$\nu$B). In this work, we perform a systematic study of the diffuse UHECR-boosted C$\nu$B flux including elastic
neutrino–nucleon scattering (ES), coherent elastic
neutrino–
nucleus scattering (COH), incoherent
neutrino–
nucleus scattering (INCOH),
baryon-resonance production (RES), and deep inelastic scattering (DIS). For the UHECR flux, we use mixed-composition spectra obtained from the UHECR propagation code PriNCe and from the H3a and H4a implementations of the Hillas model, together with SFR, QSO, and GRB source
evolution models. We find a clear hierarchy of scattering channels as a function of boosted
neutrino energy. The coherent scattering dominates at low-energy
neutrino flux for heavy
nuclear components, while ES and INCOH become important once individual nucleons are resolved. The RES channel gives a non-negligible contribution in the high-energy region, and DIS appears only at the highest energies and is most visible for the H4a case. Using current IceCube and Pierre Auger Observatory data, we obtain upper limits on the C$\nu$B overdensity. Our results show that reliable predictions of the UHECR-boosted C$\nu$B signal require a combined treatment of the relevant SM scattering channels, UHECR composition, source
evolution, and the
neutrino mass spectrum.
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Superconductivity
Cavity-enhanced superconducting response in an underdoped cuprate
Angela Montanaro, Vadim Plastovets, Nitesh Khatiwada et al. (+15 more)
Superconductors carry electrical current without resistance when paired electrons condense into a coherent macroscopic
quantum state. In underdoped cuprates, evidence suggests that pairing-related correlations and superconducting fluctuations can survive above the temperature at which global coherence is lost, pointing to phase fluctuations as a key limitation on superconductivity in this regime. Motivated by recent demonstrations of cavity-modified collective states in
quantum materials, we investigate whether superconducting coherence can be stabilized by engineering the electromagnetic environment of the
superconductor. We study an underdoped YBa$_2$Cu$_3$O$_{7-\delta}$ thin film in a tunable terahertz cavity formed with a semi-transparent gold mirror. From temperature-dependent terahertz transmission measurements, we find that the cavity enhances the superconducting response below the critical temperature, with an increase of the inferred superfluid weight. The effect becomes more pronounced at smaller cavity lengths and is accompanied by an upward shift of the superconducting onset temperature. Calculations based on a cavity-coupled model for phase-fluctuating
superconductors capture these trends and support an interpretation in terms of cavity-enhanced phase stiffness. These results showcase the potential of cavity engineering for designing emergent functionalities in correlated systems.
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All authors Angela Montanaro, Vadim Plastovets, Nitesh Khatiwada, Jacopo Fiore, Giacomo Jarc, Abdullah Alabbadi, Antonio Mastropasqua, Enrico Maria Rigoni, Shahla Y. Mathengattil, Simone Dal Zilio, Francesca Fassioli Olsen, Fabio Novelli, Stephan Winnerl, Michael A. Sentef, Dante M. Kennes, Andrew J. Millis, Francesco Piazza, Daniele Fausti
Materials Science
Tunable Electronic and Transport Properties of Biphenylene via Fluorination and Disorder
Lucas Soares Sousa, Felipe Crasto de Lima and Roberto Hiroki Miwa
Biphenylene (BPN) network is a newly synthesized 2D carbon allotrope hosting anisotropic Dirac electronic states. Here, we investigate how fluorination and correlated chemical disorder modify the electronic structure and charge transport of fluorinated biphenylene (F/BPN) using density functional theory, Wannier-based tight-biding
Hamiltonian, and
quantum transport simulations. We show that fluorination reshapes the transport response of BPN, producing concentration-dependent anisotropic conduction regimes. For pristine and ordered fluorinated systems, we identified the emergence of negative differential resistance (NDR) and a bias-induced inversion of the preferred transport direction, from armchair to zigzag and vice versa. In contrast, disorder suppresses the NDR, driving the system toward an approximately Ohmic transport regime. At high fluorine coverage, we further observed a nonmonotonic dependence of the armchair current on adatom concentration, which we attribute to the formation of correlated quasi-linear fluor conformation that promote armchair-oriented C-$\pi$ transport channels while simultaneously suppressing transport along the zigzag direction. Our results demonstrate that correlated fluorination can be used as an active mechanism to engineer electronic transport.
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Astrophysics of Galaxies
Variability in Cosmological Hydrodynamical Simulations: how Stochastic Processes, Numerical Effects, and Reproducibility Limits impact Predictability
Chaitra, Antonio Ragagnin, Milena Valentini et al. (+3 more)
Cosmological hydrodynamical simulations are powerful tools for studying
galaxy formation, yet their predictive precision is limited by
stochastic variability and numerical uncertainty. We quantify this variability using four identical realizations of a zoom-in
galaxy-cluster simulation evolved with OpenGadget3 under tightly controlled compiler, library, and hardware settings. Variability is measured through the properties of matched
galaxies across repeated runs, including a mixed linear model that separates run-to-run variation from within-run noise. Variations of approximately $10$-$25\%$ are found in
galaxy dark matter and
stellar masses for the baseline simulations. The variability trending above the shot-noise floor reflects the combined effects of
stochastic star formation and feedback regulation, and is further amplified when black hole physics is included. Furthermore, our results indicate that feedback acts to regulate variability, reducing scatter in both
stellar and black hole masses. Our inference from run-to-run variation indicates a noise-dominated regime that remains statistically reproducible, despite individual realization differences. These results establish baseline, noise-dominated variability estimates at low resolution, demonstrate how feedback modulates predictability, and provide a statistical framework for future studies of reproducibility in cosmological hydrodynamical simulations.
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All authors Chaitra, Antonio Ragagnin, Milena Valentini, Giuseppe Murante, Stefano Borgani, Giuliano Taffoni
High Energy Astrophysical Phenomena
The Chirp-Mass Ladder: A New Rung Emerges
Vaibhav Tiwari
We study the binary black hole (BBH) population observed through gravitational waves (GWs) using 256 events from the latest release of GWTC-5.0. The inferred chirp-mass distribution shows prominent peaks at approximately $7.5M_{\odot}$, $14M_{\odot}$, and $27M_{\odot}$, with subsequent peaks spaced by approximately a factor of two. A parsimonious explanation for this structured distribution is a hierarchical merger scenario, in which the first peak arises from mergers of black holes of
stellar origin, and higher-mass peaks arise from repeated mergers. Notably, with the addition of new observations, an intermediate peak near $19M_{\odot}$ emerges. This feature was anticipated in earlier work as a consequence of intergenerational mergers involving second- and third-generation (G) black holes, highlighting the predictive expectations of the hierarchical-merger interpretation. Furthermore, two groups of $1G+2G$ mergers recently reported in separate studies can be understood as distinct rungs—$1G+2G$ and $3G+4G$—within this hierarchical chirp-mass ladder, a unification that describes both
spin transitions with a single mechanism. Although we observe expected correlations between mass ratios and
spins in multiple events across the mass range, the lack of clear signatures across all rungs invites investigation into the role of hierarchical mergers in shaping the BBH population.
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Instrumentation and Methods for Astrophysics
Sustainability as a design parameter in the early development of the Wide-field Spectroscopic Telescope
L. Fréour, E. Burtin, R. Bacon et al. (+13 more)
The proposed Wide-field Spectroscopic
Telescope, a next-generation
telescope facility with a 12-meter primary mirror that may be operational in the 2040s, is integrating sustainable considerations from the early design stage. Our preliminary analysis identifies two primary sources of environmental impact that can be mitigated during the design process. First, we are conducting a life-cycle assessment (LCA) to quantify the environmental impact of the ~250 spectrographs and the detector cooling systems across the
telescope's three instruments, from construction through operation. The carbon footprint estimated through this LCA has been included as a trade-off parameter in the design choices. Second, the WST is expected to produce 1-3 PB/year, requiring careful evaluation of data processing and storage strategies. We explore approaches to monitoring and reducing the carbon footprint associated with data management. Bringing environmental factors into the design process from the start gives us the chance to weigh sustainability alongside scientific performance and cost. By treating the carbon footprint as a core design consideration, we aim to make progress toward more responsible astronomy.
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All authors L. Fréour, E. Burtin, R. Bacon, B. Ziegler, S. Randich, A. Pecontal, P. M. Weilbacher, C. Cudennec, D. Buffat, S. D'Auria, A. Meoli, L. P. Cassarà, P. Dierickx, V. Mainieri, P. Franzetti, D. Lee
Mesoscale and Nanoscale Physics
Highly nonlinear Moiré exciton and trion polaritons
Arnab Barman Ray, Trevor Ollis, Fei Cheng et al. (+3 more)
Moiré multi-layers of transition metal dichalcogenides have been shown to exhibit optical responses that are endowed with a richness that is absent in single monolayers. Much of this can be attributed to the Moiré superlattice that modulates the electronic landscape of these
heterostructures. Strongly coupled layer-hybridized
excitons in $\text{MoSe}_2 / \text{WS}_2$ heterobilayers have been shown to exhibit enhanced optical nonlinearities. In this work we strongly couple layer hybridized
excitons and trions in n-doped $\text{MoSe}_2 / \text{WS}_2$ heterobilayers inside an optical microcavity. We find that the additional Lindhard screening from dopant electrons and the formation of trions result in a strikingly non-monotonic nonlinear response. The absence of electron capture in the Moiré superlattice plays a crucial role, promising very large second-order nonlinearities. In this work, trion polaritons manifest as high velocity hot polaritons, reaching nominal
diffusion lengths approaching 100 microns.
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All authors Arnab Barman Ray, Trevor Ollis, Fei Cheng, Adam L. Freidman, Aubrey T. Hanbicki, Anthony Nickolas Vamivakas
Pattern Formation and Solitons
Energy localization in damped nonlinear disordered metastructures under superharmonic resonance
Lucas José Dantas Alcântara, Arthur Silva Barbosa, Rafael da Silva Raqueti et al. (+3 more)
This paper proposes a framework for energy localization in nonlinear oscillator chains operating in non-fundamental resonance, with emphasis on superharmonic regimes. The system is modeled as a metastructure composed of Duffing oscillators with both linear and nonlinear coupling, incorporating disorder-induced periodicity breaking. Under the assumption of strong excitation, the method of multiple scales is employed to derive the governing equations for
soliton dynamics. At first-order perturbation, the classical form of the Nonlinear Schrödinger Equation emerges, whereas second-order analysis yields a previously unreported equation arising from the restitution of time scales. Analytical and numerical results demonstrate the nucleation of
solitons in both hardening and softening regimes, based on two approaches: direct time-domain simulations from initially motionless states and numerical continuation in the frequency domain. A key finding is the distinct role of phase in superharmonic resonances compared to the primary resonance; specifically, the coexistence of multiple frequency components in the steady-state response precludes interpreting the
soliton directly as a displacement envelope. Instead, the resulting secular terms captures the
soliton associated with the resonant contribution, while transient components remain present under superharmonic excitation. Furthermore, robustness against disorder uncertainty is assessed by determining the tolerance levels that preserve the phenomenon. These results support the development of vibration control strategies aimed at mitigating the increase in resonant frequencies associated with the
geometric downscaling of mechanical systems.
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All authors Lucas José Dantas Alcântara, Arthur Silva Barbosa, Rafael da Silva Raqueti, Najib Kacem, Leopoldo Pisanelli Rodrigues de Oliveira, Noureddine Bouhaddi
Nuclear Experiment
Hyperon ($\Lambda$) polarization along the beam axis in Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 5.36$ TeV
ALICE Collaboration
The measurement of hyperon ($\Lambda$ and $\overline{\Lambda}$) polarization along the beam axis in Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 5.36$ TeV using the ALICE detector is presented. The polarization, arising from vorticity components induced by anisotropic flow, is studied relative to the second- and third-order event planes. The measured polarization exhibits clear azimuthal sine modulations, providing the first observation of polarization along the beam direction measured relative to the third-order event plane at the Large
Hadron Collider. The values of the polarization measured with respect to the second-order event plane relative to the second harmonic event plane are consistent with previous measurements at $\sqrt{s_{\rm NN}} = 5.02$ TeV and show improved statistical precision owing to the larger data sample. Comparisons with hydrodynamic calculations indicate that the measured polarization is sensitive to the bulk viscosity and the vortical structure of the
quark-
gluon plasma, offering new constraints on its transport properties. In particular, the polarization measured relative to the third-order event plane is expected to provide an additional and independent input to constrain both bulk and shear viscosities of the
quark-
gluon plasma.
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Optics
Kerr Soliton Generation in Ultra-Compact Photonic Devices
Garrett J. Beals, Yun Zhao, Sai Kanth Dacha et al. (+4 more)
Chip-based nonlinear photonics offer the capability to integrate devices with all the requisite photonic components (e.g., filters, couplers, detectors) into highly compact form factors. This offers the possibility of making the devices scalable, robust, and manufacturable. Such integrated photonic devices will enable applications in optical communications, precision metrology, microwave generation, and
LIDAR. However, thermal instabilities represent a major hurdle in the deterministic operation of nonlinear optical processes in such integrated resonant structures such as microresonators. In this work we demonstrate deterministic and highly stable Kerr
soliton comb generation in tight-spiral microresonators with comb spacings as low as 16 GHz. We perform a comprehensive experimentally-validated thermal model of such compact microresonators and reveal non-trivial thermally-driven instabilities governing the cavity
soliton dynamics. We design and implement a fast feedback loop on the devices to overcome thermal perturbations and stabilize cavity-
soliton states, including those that are otherwise unstable, and to allow for controlled transitions between the
soliton states. Our approach enables the realization of thermally-stable highly compact
soliton microcomb devices in a wide variety of photonic platforms.
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All authors Garrett J. Beals, Yun Zhao, Sai Kanth Dacha, James Eckstein, Karl McNulty, Michal Lipson, Alexander L. Gaeta
Quantum Gases
Universal scaling and relaxation in decaying turbulence of Bose gases
Arnol D. García-Orozco, Michelle A. Moreno-Armijos, Sarah Sab et al. (+2 more)
Understanding the relaxation dynamics of isolated
quantum systems remains a central challenge in nonequilibrium physics. In this short review, we discuss recent experimental and theoretical advances in universal dynamics of turbulent Bose gases, with particular emphasis on nonthermal fixed points and wave
turbulence in our experimental system at the São Carlos Institute of Physics of the University of São Paulo. We highlight the emergence of self-similar scaling behavior and its connection to particle and energy transport across momentum scales. In addition, we discuss an approach in which a differential equation has a universal scaling solution, providing a practical framework for extracting universal exponents from limited regions of the momentum distribution. Furthermore, we recap experimental observations of direct and inverse cascades in a three-dimensional trapped Bose–Einstein condensate, revealing distinct relaxation stages governed by universal scaling laws. These results demonstrate that
turbulence plays a key role in far-from-
equilibrium dynamics, offering a unified perspective on transport processes and thermalization in
quantum many-body systems.
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All authors Arnol D. García-Orozco, Michelle A. Moreno-Armijos, Sarah Sab, Amilson Fritsch, Vanderlei Salvador Bagnato
Medical Physics
MERMAID-v1 PET Scanner Prototype: Initial Characterization and First Zebrafish Scans
Steven Seeger, Hong Phuc Vo, Rebecca Kantorek et al. (+6 more)
MERMAID-v1 is a prototype PET scanner designed to support biomedical research involving adult zebrafish and similar species. The current experimental setup has been characterized, and scans of various phantoms, as well as adult zebrafish have been conducted. A dedicated reconstruction software was implemented, including accurate modeling of the parallax effect. The average energy resolution was 21.6% (FWHM at 511keV), with no significant dead-time effects observed for activities up to 18MBq. The absolute sensitivity at the center of the field of view (FOV) ranged from 0.06% to 0.31%, depending on the energy window (from 450-550 to 300-600keV), reflecting the limitations of the current two-head configuration. In the central 12mm of the transaxial FOV, the averaged spatial resolution is approximately 0.77mm (FWHM) transaxially and 0.66mm axially, as evaluated using a point source. Image quality was assessed using a downscaled NEMA-inspired IQ phantom and a 3D-printed Derenzo phantom. The reconstructed images suggest a spatial resolution around 0.7mm - 0.8mm, despite the lack of depth-of-interaction information. The first ex- and in-vivo PET scans of adult zebrafish were successfully performed, showing detectable tracer uptake in organs such as the
brain and eyes despite low initial activity levels. These results confirm MERMAID-v1 capability to obtain useful results from the acquired data from living, anesthetized fish in a water-filled imaging chamber. While no scatter, attenuation, or efficiency corrections have yet been implemented, this work establishes a working proof-of-concept for dedicated PET imaging of small aquatic vertebrates. Future developments will focus on developing correction techniques, expanding the detector array, and integrating complementary modalities such as CT.
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All authors Steven Seeger, Hong Phuc Vo, Rebecca Kantorek, Magdalena Kołodziej, Ezzat Elmoujarkach, Caroline Florack, Jorge Roser, Christian Schmidt, Magdalena Rafecas
High Energy Astrophysical Phenomena
A Semi-Analytical Loss Cone Theory for Tidal Disruption Event Rates Around Kerr Black Holes
Wenkang Xin
A
tidal disruption event (TDE) occurs when a
star is scattered onto a near-radial orbit and is torn apart by a black hole (BH)'s
tidal field. The angular momentum threshold for disruption is set by general relativistic
tidal dynamics, while the supply of
stars to the disruption zone is governed by Newtonian
stellar dynamics. A spinning BH breaks the spherical
symmetry of the disruption boundary, so a
star's survival depends on both the magnitude and the orientation of its angular momentum. Existing treatments either assume a non-spinning BH or rely on numerical simulations of spinning BHs. We develop the first semi analytical framework that incorporates
spin-dependent loss cone boundaries into TDE rate theory. Using a novel
tidal tensor formalism, we compute inclination-dependent thresholds for
tidal disruption and direct capture by the event horizon. We then revisit the classical one dimensional loss cone problem with nested disruption and capture boundaries, deriving a closed form capture fraction valid across all loss cone regimes. Finally, we formulate a two dimensional Fokker–Planck equation describing simultaneous
diffusion in angular momentum magnitude and orientation. Through a perturbative treatment, we demonstrate that while the Kerr disruption boundary induces a first-order bias favouring the disruption of retrograde
stars, the global TDE rate is remarkably insensitive to black hole
spin. This approach offers a tractable route to including
spin and orbital inclination in population-level TDE studies.
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Materials Science
Coupled spin dynamics in epitaxial trilayer heterostructures of ferrimagnetic garnet
A. Del Giacco, M.J. Gross, O. Wojewoda et al. (+9 more)
The magnetization dynamics of an all-garnet trilayer consisting of Y3Fe5O12/Y3Fe3Al2O12/Y3Fe5O12 (YIG/YIAG/YIG) is analysed. The two
magnetic YIG layers, separated by a 4 nm thick paramagnetic YIAG layer, are coupled via dipolar interactions leading to the formation of hybrid
magnon modes distinct from the modes found in a single YIG layer. The YIAG exchange-decouples the YIG layers while enabling
lattice coherence, maintaining the low damping of the YIG. Both
ferromagnetic resonance and micro-Brillouin light scattering measurements were used to characterize the sample and its hybrid dynamics, which showed excellent agreement with an analytical reciprocal space model of
spin-wave dynamics and with micromagnetic modeling of a dipolarly coupled
magnetic heterostructure.
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All authors A. Del Giacco, M.J. Gross, O. Wojewoda, L. Menna, T. Grossmark, P. Lauer, V. Levati, S. Kurdi, E. Albisetti, D. Petti, M. Urbanek, C.A. Ross
Earth and Planetary Astrophysics
Transit timing and starspot-induced transit depth variations in the $\sim$17 Myr old HIP 67522 system
H. Chakraborty, M. Lendl, A. Nigioni et al. (+27 more)
HIP 67522 is a one of the youngest multi-planetary systems discovered to date. The 17 Myr-old, Sun-like
star is part of the Scorpius-Centarus OB association and is known to host two Saturn-sized
planets in near 2:1 mean motion resonance. We analysed photometric transits observed with the CHaracterising
ExOPlanet Satellite (CHEOPS), the Transiting
Exoplanets Survey Satellite (TESS) and multiple ground-based facilities to search for transit timing variations induced by
planet-
planet gravitational interactions, as well as transit depth variations, linked with the changing coverage of active regions on the
stellar surface. We do not detect any transit timing variations for HIP 67522 b exceeding two minutes, contrary to previous results from the James Webb Space
Telescope. In addition, we found that the observed transit depth of
planet b changes strongly over time, with a >30% variation in amplitude. The high sensitivity and blue bandpass of the CHEOPS satellite also enabled us to identify multiple starspot crossings and measure their properties, including spot temperatures and sizes. We also measured the shear of the host
star's differential rotation by modelling the out-of-transit photometric variability and concluded that HIP 67522 exhibits a supersolar differential rotation. Based on internal structure models and
planet formation simulations, we find that HIP 67522 b likely have more than 20% of their mass made of gaseous envelopes at their current age. Evolutionary simulations further indicate that both
planets in the system will experience significant photoevaporation, evolving into either Earth size
planets with completely stripped atmospheres or sub-Neptune-sized
planets.
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All authors H. Chakraborty, M. Lendl, A. Nigioni, J.A. Egger, J.M. Almenara, M.P. Battley, A.G.M. Pietrow, J. Venturini, A. Heitzmann, B. Akinsanmi, I. Apergis, D. Bayliss, J.P. Faria, A.D. Feinstein, J.F. Fernández, E. Fontanet, E. Gillen, E. Ilin, T. Jestin, J.S. Jenkins, E.J. Lößnitz, J. McCormac, C. Modrasini, F. Neiradiaz, H.P. Osborn, D.J.M. Petit dit de la Roche, S. Saha, A.M.S. Smith, S. Ulmer-Moll, P.J. Wheatley