Physics and Society · Cross-listed from cs.CY
Beyond Resilience – A Conceptual Framework for Civic Ascent
Alexandros Washburn and Carlo Lipizzi
The resilience literature measures urban performance as recovery: the degree to which a city returns to its pre-shock baseline. This paper develops a stronger concept – civic ascent – as part of a broader research program on the ethology of coupled
agent-environment systems, of which the city is the deepest available empirical instance. Civic ascent is defined as the condition in which a city emerges from shock with higher functional capacity than before. We develop a conceptual framework in the ethological tradition, treating the city as a coupled system of three slow state variables – topos (physical structure), nomos (institutional structure), and hexis (civic judgment) – together with a fast affective channel (delta) through which shocks to topos and nomos reach hexis. The framework distinguishes three structurally distinct pressures on civic systems: shocks (discontinuities in T or M), decay (continuous
entropy), and leakage (active extraction of civic surplus into non-civic pools). The ascent condition is that reinforcement from cross-coupling of T, M, and H exceeds the combined loss from decay and leakage. Post-shock ascent is measured by a normalised improvement index A(T) applied to a composite civic performance signal P(t) constructed from scale-adjusted key performance indicators, distinguishing intrinsic civic ascent from demographically driven growth. New York City after September 11, 2001, is proposed as the primary empirical case; the operational measurement program is specified in the companion NYC Civic Data Map (Washburn 2026c, 133 KPIs) and executed in Paper 2. The reader for whom only the urban contribution is of interest will find it complete in itself; the reader interested in the larger program will find this paper its formal core.
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Materials Science
Intrinsic Ductility from Shear Amorphization: From Pure Metals to Multi-Principal-Element Alloys
Morgan R. Jones, Duane D. Johnson and Nicolas Argibay
Direct links between electronic structure and intrinsic ductility remain elusive for metals. A framework is proposed that reduces the complexities of valence charge distribution, band filling, and shear strain effects into structure-property relationships describing the intrinsic ductility of metals and
alloys. Rather than relying on
crystal cleavage and dislocation nucleation at preexisting crack tips, we show that a lower energy fracture criterion, i.e., the activation energy density for amorphization, enables accurate predictions of both intrinsic ductility and ductile-to-brittle transition temperatures. From analytical expressions and tabulated ab-initio stiffness constants,
lattice parameters, and binary interaction energies, we present a unified theory that reconciles ductile flow in pure metals and solid-solution
alloys. Phase diagrams generated for the Nb-Ta-V-Ti system simultaneously explain its high strength and room-temperature tensile ductility, validating this framework as a practical one for rapid design of structural multi-principal-element
alloys.
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Optics
Discrete phase symmetry of stationary states in bichromatically pumped Kerr microresonators
B. N. Nougmanov, V. L. Gorshenin, N. S. Tatarinova et al. (+3 more)
Bichromatically pumped Kerr microresonators can exhibit phase multistability due to four-wave mixing between the pump modes and the generated modes. Here, we analyze the
symmetry structure of stationary solutions within the coupled-mode description of these systems. We show that the two-pump coupled-mode equations belong to a broader class of models with equally spaced driven modes and mode-dependent nonlinear coupling coefficients, losses, and detunings. In this generalized setting, each stationary solution generates a finite family of stationary solutions under a discrete phase transformation. For each nonzero modal amplitude, the number of distinct phase values within a
symmetry orbit is determined solely by the mode index and the pump-mode spacing. We show that the phase-counting rule also applies to modes outside the interval between the two pumps, where it reproduces the
symmetry observed within that interval. In addition, the same phase-multistability mechanism can arise in configurations with multiple pump modes, provided that adjacent pumps are separated by the same number of resonator modes.
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All authors B. N. Nougmanov, V. L. Gorshenin, N. S. Tatarinova, D. A. Chermoshentsev, I. A. Bilenko, F. Y. Khalili
Materials Science
Water Flow Through Polar and Non-Polar Nanopores: Insights from Multiscale Simulations
Elizane E. de Moraes, João Victor Lemos Valle, Bruno H. S. Mendonça et al. (+3 more)
Global water stress has emerged as a critical challenge, driving the search for advanced membrane materials that enable efficient, selective water filtration and transport. In this context, two-dimensional nanoporous membranes provide an ideal platform to elucidate how atomic-scale structure and electronic polarization govern water flow under extreme confinement. In this study, we employ multiscale simulations to investigate the effect of water flow through nanopores in
graphene and hexagonal boron nitride (hBN) membranes. Our results reveal significantly higher water flow in hBN membranes than in
graphene. This enhanced flow is attributed to the asymmetry of the hBN pores, which induces an electric dipole moment, as confirmed by
quantum-mechanical (QM) calculations. Classical molecular dynamics simulations further demonstrate that water molecules exhibit a random distribution with no preferential orientation near the
graphene pores, whereas hBN induces strong structuring. Furthermore, hybrid
quantum mechanics/molecular mechanics (QM/MM) simulations indicate that the dipole moment of the hBN pore increases in the presence of water, as evidenced by the average charge distribution. Conversely, the symmetric nature of
graphene pores results in non-polar characteristics, as verified by both QM/MM and QM calculations. These findings provide valuable insights into the distinct water-transport properties when flowing through
graphene and hBN nanopores, with potential implications for designing advanced nanofiltration membranes.
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All authors Elizane E. de Moraes, João Victor Lemos Valle, Bruno H. S. Mendonça, Ernane de Freitas Martins, Hélio Chacham, Pablo Ordejón
Space Physics
Plasma frequency waves in Earth's electron foreshock
Daniel B. Graham, Yuri V. Khotyaintsev, Mats André et al. (+2 more)
At Earth's quasi-perpendicular bow shock, electrons can be reflected and accelerated to high velocities, forming beams. These beams excite Langmuir and beam-mode waves, which can then be converted to
radio waves. We aim to understand the properties and
evolution of Langmuir waves excited in the electron foreshock region using the Magnetospheric Multiscale (MMS) mission. We use fields and particle data from the four MMS spacecraft to investigate the properties of Langmuir/Z-mode waves in Earth's electron foreshock. MMS provides extended high-resolution snapshots of the three-dimensional electric field, enabling detailed analysis of wave properties. Probability distributions of the electric field are used to investigate the
evolution of the waves and the role of density fluctuations. Distinct spectral peaks near the electron
plasma frequency are often observed, suggestive of simultaneous observations of beam-mode and Langmuir waves, as well as nonlinear electrostatic decay of Langmuir waves or reflection off density gradients. In addition, the electric fields often have large perpendicular components, consistent with Z-mode waves. The statistical results show that the electric fields are largest near the electron foreshock boundary with the
solar wind. Both the parallel and perpendicular components of the electric field exhibit close to log-normal probability distribution functions, consistent with predictions from
Stochastic Growth Theory. These results suggest that small-scale density perturbations in the ambient
plasma, in addition to nonlinear three-wave decay, are crucial to the
evolution of Langmuir waves and the generation of
radio waves. These results apply to Langmuir waves in the
solar wind, such as in Type II and Type III
solar radio burst source regions, where the same density fluctuations are expected and large-amplitude Langmuir waves with similar properties are observed.
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All authors Daniel B. Graham, Yuri V. Khotyaintsev, Mats André, Andris Vaivads, Iver H. Cairns
Soft Condensed Matter
How alignment controls heat transport in polymer chains with kinks?
Igor V. Parshin, Igor V. Rubtsov and Alexander L. Burin
Thermal transport in
polymer chains is commonly attributed to ballistic propagation of long-wavelength acoustic
phonons, which act as Goldstone modes protected by translational
symmetry, whereas transport by higher-frequency
phonons is suppressed by Anderson localization. Consistent with this picture, highly aligned
polymers exhibit exceptionally high thermal conductivity, while poorly aligned
polymers are orders of magnitude less conductive and serve as efficient thermal
insulators. Here we show that this striking sensitivity to molecular
alignment originates from acoustic-
phonon scattering by molecular kinks. In the long-wavelength limit, longitudinal acoustic (LA)
phonons are completely reflected by a single kink, whereas transverse acoustic (TA)
phonons exhibit a universal transmission coefficient of one half. We show that the strong reflection results from the breaking of translational
symmetry caused by the change in molecular-axis direction at the kink, while the universal TA transmission originates from virtual scattering through an evanescent transverse Bloch mode. The resulting strong suppression of long-wavelength
phonon transport dramatically reduces the thermal conductivity of poorly aligned chains. These findings identify kink engineering as a promising strategy for controlling thermal transport in polymeric materials.
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Mesoscale and Nanoscale Physics
Nonmonotonic temperature dependence of the thermopower of atomic-size gold contacts
Thomas B. Möller, Marcel Strohmeier, Johannes Boneberg et al. (+3 more)
We report measurements of the thermopower of atomic-size gold contacts realized by the mechanically controllable break junction (MCBJ) technique over a temperature range from 18 K to 295 K. A thermometer included in the lithographic structure close to the constriction provides a direct measurement of the temperature increase generated by heating one side of the contact with a focused
laser beam. While the conductance histograms confirm the
quantum nature of the transport, we observe a nonmonotonic temperature dependence of the ensemble-averaged thermopower with a minimum of $-2\,\mu$VK$^{-1}$ at about 150 K. The values for the thermopower obtained at the lowest and the high temperature are compatible with values reported in the literature, but the nonmonotonic behavior in between disagrees with the expected linear dependence for
quantum coherent conductors described by the Landauer formula. We develop a theoretical model based on an energy dependent transmission function that qualitatively reproduces the nonmonotonic behavior, but fails quantitatively. We therefore interpret our data as a result of
phonon contributions to the thermopower beyond the Landauer model and with opposite sign than the classical
phonon drag known from bulk systems. Our findings show that, firstly, the thermopower gives important insight into the transport properties of atomic-size structures and second that the linear approximation of the Landauer model has to be used with caution when studying more complex transport properties even for atomic contacts from free-electron metals.
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All authors Thomas B. Möller, Marcel Strohmeier, Johannes Boneberg, Paul Leiderer, Wolfgang Belzig, Elke Scheer
Solar and Stellar Astrophysics
X-ray Emission and Stellar Ages of Sun-Like Stars
Breanna A. Binder, Edward W. Schwieterman, Alison Farrish et al. (+4 more)
We present an analysis of XMM-Newton and Chandra observations of 85 nearby main-sequence FGK
stars with age estimates ranging from 0.2-12 Gyr. We measure quiescent 0.3-10 keV luminosities, variability metrics, and multi-temperature thermal
plasma spectral parameters. Quiescent spectra are typically described by three characteristic
plasma components ($kT\approx0.1$, 0.4, 0.8 keV); the fraction of flux from $T\ge7$ MK rises with X-ray surface flux, reaching $\sim$50% for $F_X\gtrsim10^6$ erg cm$^{-2}$ s$^{-1}$. We derive relations between emission measure-weighted coronal temperature and both $L_X$ and $F_X$, enabling temperature-informed count-rate conversions for faint sources. We quantify how bandpass conversions (ROSAT 0.1-2.4 keV vs. XMM-Newton 0.3-10 keV) depend on temperature, and show that inferred ROSAT-band $L_X$ broadly follows the canonical $t^{-1.5}$ decay, while the harder band exhibits increased scatter at $>$4 Gyr. Several
stars show excess activity suggestive of age errors, inclination effects, or unresolved companions. Some of these "outlier"
stars are potential direct imaging targets for the Habitable Worlds Observatory, and detailed characterization of these
stars is needed to inform their likely influence on the atmospheric
evolution of orbiting
planets.
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All authors Breanna A. Binder, Edward W. Schwieterman, Alison Farrish, Sarah Peacock, Margaret C. Turnbull, Stephen R. Kane, Katherine Garcia-Sage
Materials Science
Extending the La Solubility Limit in Sr$_3$Ir$_2$O$_7$ through High-Pressure High-Temperature Synthesis
Cheng Peng and Weiwei Xie
La-doped
bilayer iridates provide an important platform for studying the
evolution of the
spin-orbit-assisted Mott state under electron doping, but the La solubility achieved by conventional ambient-pressure synthesis is limited. Here, we report the synthesis and physical properties of nominally La-doped (Sr$_{1-x}$La$_x$)$_3$Ir$_2$O$_7$ (x = 0.05, 0.10, 0.15, and 0.20) prepared using high-pressure high-temperature techniques. Single-
crystal X-ray diffraction refinements, supported by scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX), reveal significantly enhanced La incorporation, with nominal x = 0.05 and 0.15 corresponding to actual compositions of approximately (Sr$_{0.89}$La$_{0.11}$)$_3$Ir$_2$O$_7$ and (Sr$_{0.77}$La$_{0.23}$)$_3$Ir$_2$O$_7$, respectively. At nominal x = 0.20, the
bilayer phase is no longer stabilized and instead transforms into cubic perovskite Sr$_{1-x}$La$_x$IrO$_3$. (Sr$_{0.89}$La$_{0.11}$)$_3$Ir$_2$O$_7$ exhibits a
ferromagnetic-like transition near 186 K accompanied by
magnetic hysteresis and subtle
lattice anomalies indicative of
spin-
lattice coupling. Despite its high electron-doping level, the compound remains strongly insulating, consistent with a heavily doped localized
magnetic insulating state distinct from both parent Sr$_3$Ir$_2$O$_7$ and ambient-pressure La-doped samples. In contrast, (Sr$_{0.77}$La$_{0.23}$)$_3$Ir$_2$O$_7$ displays metal-like electronic behavior, weakened
magnetic order, and enhanced carrier delocalization, although disorder-driven localization persists at low temperatures. These results demonstrate that high-pressure synthesis substantially extends the accessible doping range of
bilayer iridates and reveals electronic and
magnetic states inaccessible through conventional synthesis routes.
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Quantum Physics
Stable, bidirectional electro-optic transduction in thin film lithium tantalate
Christopher J. Axline, Stephan Gamper, Phoebe M. Tengdin et al. (+6 more)
Efficient and stable microwave-optical transduction is a key enabling technology for distributed superconducting
quantum computing and heterogeneous
quantum networks. Electro-optic transducers based on thin-film lithium niobate (TFLN) have shown strong promise, but demonstrations to date have been limited by various factors such as low frequency bias drift, low efficiency, fabrication complexity, and scalability. Here we demonstrate the first integrated electro-optic microwave-optical transducers realized in thin-film lithium tantalate (TFLT), a material platform offering Pockels nonlinearity comparable to TFLN together with improved bias stability and high-power handling. We fabricate superconducting microwave resonators coupled to tunable photonic-molecule optical resonators using wafer-scale deep ultraviolet lithography, offering high-throughput production of hundreds of devices per wafer. Across six devices we observe coherent bidirectional conversion between C-band optical
photons and 4.9-5.5 GHz microwave
photons, with measured on-chip efficiencies and inferred single-
photon coupling rates g_0/2{\pi} ~ 1 kHz consistent with theory. Continuous operation over multiple days is achieved using a static bias field with minimal feedback, demonstrating a major operational advantage. We further characterize optical loss statistics, microwave resonator performance, and optically induced added noise under pulsed pumping, finding less than one added
photon for 100 microsecond pulses at the highest measured efficiencies. These results establish TFLT as a scalable and robust electro-optic platform for future
quantum interconnects and modular
quantum processors.
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All authors Christopher J. Axline, Stephan Gamper, Phoebe M. Tengdin, Moritz Businger, Guilhem Alma, Marina A. Roquet, Nicola Brusadin, Robin Giroud, Luis G. Villanueva
Quantum Physics
Rui Chao
Morphing
circuits are a new paradigm for
quantum error correction that relaxes hardware requirements. We present four constructions for CNOT-based CSS morphing
circuits with explicit
qubit connectivity degrees. All four constructions are specified in block
algebra notation, with entries in
algebras generated by permutation
matrices. The first three are obtained by rewriting existing surface- and color-code morphing
circuits; the fourth is a new three-round construction modeled on the 6.6.6 color code. The surface-code construction recovers the morphing
circuit of Ref. [ST25] for two-block group
algebra codes. Numerical search then instantiates these permutation
matrices using regular representations of finite groups. [ST25] M. H. Shaw and B. M. Terhal, Phys. Rev. Lett. 134(9), 090602 (2025).
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High Energy Astrophysical Phenomena
Spectroscopic modeling of ionic structure in stellar winds of high-mass X-ray binaries
G. Sanjurjo-Ferrín, V. Grinberg, I. El Mellah et al. (+6 more)
High-mass X-ray binaries (HMXBs) provide a natural laboratory to study radiatively driven
stellar winds under strong external X-ray irradiation. As the compact object moves along its orbit, the wind density and ionization structure vary with orbital phase, leaving characteristic signatures in X-ray emission and absorption features. The amplitude and morphology of this variability depend on the system geometry, including the orbital inclination (via line-of-sight and occultation effects) and the orbital eccentricity (via phase-dependent changes in the orbital separation). We present a computational framework that connects phase-resolved spectroscopic variability to the three-dimensional structure of irradiated winds, and that enables inference of physically meaningful wind–irradiation parameters within a
Bayesian setting. We combine photoionization calculations with a parametric wind description and orbital geometry to construct three-dimensional maps of density and ionization. From these maps we compute orbital-phase-dependent diagnostics, accounting for
geometric occultation and wind inhomogeneity through a clumping prescription. We then use
Bayesian inference to compare model predictions with phase-resolved observables and to quantify parameter constraints and degeneracies. The framework reproduces the main orbital-phase-dependent trends expected for irradiated winds and yields robust constraints on the system ionization balance. While combinations of wind and luminosity parameters are well constrained, individual parameters can remain partially degenerate depending on the orbital configuration and data quality. This modular and computationally efficient approach provides a route to interpret HMXB phase variability in physical terms, and offers a foundation for future extensions toward forward spectral modeling and population-level applications.
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All authors G. Sanjurjo-Ferrín, V. Grinberg, I. El Mellah, J. M. Torrejón, R. Ballhausen, J. Planelles-Villalba, S. Reyero-Serrantes, J. J. Rodes-Roca, M. Martínez-Chicharro
Mesoscale and Nanoscale Physics
Tudor Gabriel Dumitru, Anna Sitek, Gunnar Thorgilsson et al. (+3 more)
This work is motivated by the experimentally observed coherence of the supercurrent in
semiconductor nanowires covered by a half-shell metallic
superconductor, which leads to flux dependent supercurrent oscillations with period h/2e, as expected for a tubular
superconductor, i.e. Little-Parks oscillations. We perform microscopic model calculations and compare the results for full and half metallic shells. We use an effective
Hamiltonian derived from the Green's function of the proximitized
semiconductor nanowire, where the presence of the
superconductor is represented by a self energy. Furthermore, we incorporate the electrostatic band-bending at the metal-
semiconductor interface as a rectangular narrow
quantum well on the
semiconductor side. The properties of the eigenstates of the effective
Hamiltonian are determined by the spatial profile of the corresponding transverse modes in the normal state. For half-shell wires, transverse modes with high-enough energy expand outside the interface
quantum well and generate eigenstates with mixed electron-hole character that surround the entire circumference of the nanowire, similar to eigenstates of the full-shell system. We identify these states as being responsible for the observed Little-Parks effect.
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All authors Tudor Gabriel Dumitru, Anna Sitek, Gunnar Thorgilsson, Sigurdur I. Erlingsson, Tudor Dan Stanescu, Andrei Manolescu
Applied Physics · Cross-listed from math.NA
The three-dimensional Neumann Green's function for general surfaces: singular asymptotics and boundary integral methods
Alan E. Lindsay, Andrew J. Bernoff, Tristan Goodwill et al. (+1 more)
We present an asymptotic analysis and high-order boundary integral method for the three-dimensional Neumann Green's function in general closed and smooth geometries. The Neumann Green's function is a fundamental quantity which arises in numerous fields of science and engineering. In the application of singular perturbation methods to strongly localized reactions and diffusive transport, the Green's function plays the key role in mediating global dynamics. However, this essential quantity can only be determined in closed-form for a limited set of geometries. The Green's function for the
Laplacian is an
elliptic problem with a Dirac forcing term. Accurate resolution of the solution requires a careful decomposition into a singular and a regular part. The bulk scenario is where the source is placed off surface and the singularity is given by the free-space function. In the surface case, where the source is placed at a curved point on the boundary, we use asymptotic analysis to determine a three-term singularity structure. With explicit knowledge of these singularities, we develop a high-order boundary integral method for the determination of the remaining regular part. To resolve the singular boundary data, our integral method uses a custom discretization with Duffy patches near the source. We validate our method using several test cases in which closed-form solutions can be developed, including spheres, prolate spheroids and constructed domains. We demonstrate the applicability of our method to address some open problems in narrow capture theory.
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All authors Alan E. Lindsay, Andrew J. Bernoff, Tristan Goodwill, Jeremy G. Hoskins
Materials Science
Site Preferences and "Coloring Problem" in Cu-doped BiMn$_7$O$_{12}$ Quadruple Perovskite
Cheng Peng, Mingyu Xu, Yang Zhang et al. (+3 more)
Lightly Cu-doped BiMn$_7$O$_{12}$ (x = 0.05, 0.10, and 0.15) was investigated using high-pressure synthesis, single-
crystal X-ray diffraction, pair distribution function (PDF) analysis, STEM,
magnetic measurements, and first-principles calculations. All compositions retain an average monoclinic $I$2/$m$ structure, while Cu substitution progressively suppresses the monoclinic distortion and drives the
lattice toward a pseudo-cubic metric
symmetry. PDF analysis reveals increasing local structural disorder and reduced medium-range coherence with increasing Cu concentration, despite preservation of the overall quadruple-perovskite framework. Single-
crystal refinements indicate enhanced electron density at the octahedral Mn B sites, suggesting preferential Cu occupation within the MnO$_6$ network rather than the conventional square-planar sites expected for Cu$^{2+}$.
Magnetic measurements reveal two characteristic anomalies near $T_1$ ~ 100-120 K and $T_2$ ~ 50-60 K, together with pronounced
magnetic irreversibility, field-dependent hysteresis, and unsaturated magnetization. Increasing Cu concentration progressively suppresses the low-temperature
magnetic state and weakens the field-induced moment. First-principles calculations favor Cu occupation at the square-planar sites, contrasting with the experimental refinements and highlighting strong competitions among local bonding, short-range disorder, and metastability in this highly frustrated quadruple perovskite system.
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All authors Cheng Peng, Mingyu Xu, Yang Zhang, Ismail El Baggari, Jie Li, Weiwei Xie
Chemical Physics
Fine-tuning MLIP foundation models: strategies for accuracy and transferability
Tamás Lajos Tompa, Eszter Varga-Umbrich, Ilyes Batatia et al. (+3 more)
Adapting machine-learned interatomic potential (MLIP) foundation models to specialised tasks through fine-tuning is an increasingly important practice, yet systematic guidance on when and how to fine-tune is currently limited. We evaluate seven fine-tuning strategies – naive full-parameter updates, two layer-freezing variants, Low-Rank Adaptation (LoRA), multihead replay, pseudolabelled replay, and replay combined with LoRA – across five chemically diverse
benchmarks (aqueous NaCl, ice polymorphs, S$_\mathrm{N}$2 reactions, SPICE biomolecules, and lithium electrolytes), three generations of foundation models, and training sets spanning five orders of magnitude. To support this evaluation we implement three capabilities in the MACE codebase: LoRA adapted for equivariant message-passing architectures, including both scalar and equivariant linear layers; pseudolabelled replay, which decouples the replay data source from the original pretraining corpus; and model-aware atomic reference energy (E0) reestimation for fine-tuning workflows. We find that foundation model quality, correct E0 initialisation, and well-chosen hyperparameters are prerequisites whose impact routinely exceeds that of the fine-tuning strategy itself. Once these prerequisites are met, most strategies achieve strong target-task accuracy, consistently surpassing models trained from scratch. The practical distinction depends on deployment scope: naive fine-tuning offers the best convergence for single-system applications, while multihead replay – with either original or pseudolabelled data – is the only approach tested that consistently preserves out-of-distribution robustness, maintaining both pretraining-distribution accuracy for broader deployment and many-body short-range repulsion.
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All authors Tamás Lajos Tompa, Eszter Varga-Umbrich, Ilyes Batatia, Alin M. Elena, Noam Bernstein, Gábor Csányi
Quantum Physics
Measurement Geometry for Quantum Random Access Codes: Beyond Nayak Bound and Toward Optimality
Seiseki Akibue, Rudy Raymond, Suguru Tamaki et al. (+1 more)
Quantum random access codes (QRACs) ask how well N classical bits can be encoded into M
qubits while allowing any single bit to be recovered. Although the Nayak bound remains the standard general upper bound on the decoding probability, numerical evidence suggests a stronger upper bound in the small-
qubit regime. In this work, we formulate the optimal decoding probability in terms of decoding measurements, reformulating QRAC design as a spectral problem for noncommuting measurements. Using this formulation, we give an elementary proof of the Nayak bound by simplifying the Chernoff-bound argument. Moreover, we refine the argument to obtain upper bounds that improve over Nayak's bound in the entire finite-size regime. The equality conditions of our bounds justify defining mutually unbiased projector-valued measurements (MUPVMs), a generalization of mutually unbiased bases. We show that decoding measurement of any two-
qubit QRAC attaining the conjectured bound must form MUPVMs. We also show that any MUPVM, assisted by one ancillary
qubit, yields a QRAC with optimal N-scaling decoding probability. Finally, we propose a new MUPVM-based construction for the (M+2,M)-QRAC family attaining the conjectured bound.
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All authors Seiseki Akibue, Rudy Raymond, Suguru Tamaki, Kosei Teramoto
General Relativity and Quantum Cosmology
Higher Dimensional Loop Quantum Black hole in de Sitter Spacetime: Quasinormal Modes and Shadow Signatures
Sara Saghafi, Kourosh Nozari and Ali Mohammadpour
We investigate the dynamical and optical properties of a higher-dimensional loop-
quantum-corrected black hole in a de Sitter background. We first analyze the horizon structure and identify the admissible nonextremal black-hole domain bounded by the extremal and Nariai configurations, ensuring the existence of distinct inner, event, and cosmological horizons for the parameter sets considered. We then examine the scalar effective potential and show that the loop-
quantum correction deforms the classical scattering barrier primarily in the strong-field region while preserving its characteristic single-barrier structure. The quasinormal modes of massless scalar perturbations are computed using time-domain
evolution with Prony extraction, the
matrix method, and the WKB approximation, showing good agreement among the three approaches. The time-domain waveform and its Prony and
matrix-frequency reconstructions provide an additional direct consistency check of the extracted ringdown spectrum. We find that loop
quantum corrections induce moderate shifts in the quasinormal spectrum, whereas the spacetime dimensionality has a much stronger impact, leading to higher oscillation frequencies and damping rates. The negative imaginary parts of all modes indicate dynamical stability against massless scalar perturbations within the explored parameter range. Comparison with the corresponding classical black-hole backgrounds shows that the
quantum-corrected quasinormal spectrum remains continuously connected to the classical
photon-sphere branch, with the loop correction producing quantitative rather than qualitative changes.
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Mesoscale and Nanoscale Physics
Luis Fernando Cardenas Castillo and Wei Chen
We show that, under a short optical pulse, the
quantum metric of Bloch states in the momentum-time (kx, ky , t) of
graphene becomes dynamic and exhibits a wave-like behavior near Dirac points. This
quantum metric wave reflects the Floquet-band structure caused by the pulse, as revealed by solving the time-dependent Schrödinger equation assuming that correlations and out-of-
equilibrium effects can be ignored. The momentum and temporal components of the metric have very distinct time dependence that persists even after the pulse has passed. In addition, the pulse also generates a Berry
curvature wave that is otherwise absent in static
graphene. The time-dependent electron densities in conduction and valence bands also give arise to a Fisher information wave that constitutes part of the
quantum metric wave, and is readily measurable by pump-probe experiments.
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General Physics
Finite Standard-Model Carrier from Timelike Codazzi Defects
Piotr Ogonowski
The inverse problem of whether protected data carried by a local Lorentzian defect can determine a finite internal gauge-and-matter carrier before microscopic dynamics are chosen is considered. For a codimension-three timelike Codazzi defect, a marking-preserving reconstruction fixes a five-dimensional complex carrier $V=C\oplus W$ with $\dim_{\mathbb C}(C,W)=(3,2)$, the global gauge form $S(U(3)\times U(2))$, a
chiral $16$-dimensional exterior packet with $k_Y=5/3$, and a norm-seven family structure. The
chiral packet has the standard algebraic $SU(5)$-
Spin$(10)$ envelope without assuming grand unification. Within a declared regularized-domain class, one constrained microscopic realization is constructed. Its distinguished branch ends at a single intrinsic terminal where the strict charge minimum and the first simple invariant-sector fixed-charge degeneracy coincide; soft-coupled readouts acquire a rank-one critical-response pole. On the rank-two exact-five moment stratum, four native
matrix moments reconstruct a five-dimensional cyclic operator up to hidden
unitary. The resulting scale-free observables lie on a one-dimensional solution
manifold with a discrete conjugate orientation. With $W/Z$ used to set its longitudinal coordinate, direct CKM and reactor/
solar data are consistent with the same
manifold, while first-row CKM normalization remains a separate transverse structural test. Existence within the stated class is established, not uniqueness. A blind determination of the longitudinal coordinate still requires the unresolved centered-response incidence; physical transport remains an independent microscopic gate.
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Astrophysics of Galaxies
Unprecedented Constraints on Gas Flows at High Redshift Using Deep JWST/NIRSpec Observations from the LyC22, EXCELS, and AURORA Surveys
Emily Kehoe, Alice E. Shapley, Adam C. Carnall et al. (+25 more)
We investigate how low-ionization gas flows in typical
star-forming
galaxies at $z\sim3$ depend on
galaxy intrinsic properties and viewing angle. For this analysis we use JWST/NIRSpec observations of rest-frame near-UV Fe II and Mg II absorption, and rest-frame optical Na D absorption. This study combines
galaxies from the LyC22, EXCELS, and AURORA surveys and contains 176, 197, and 315
galaxies, respectively, with Fe II, Mg II, and Na D coverage. Based on both individual and composite spectra, we find no statistically significant correlations between
outflow velocity and
galaxy properties. However,
galaxies with detected
outflows tend towards higher
stellar masses, SFR, and $\Sigma_{\rm SFR}$ than those without
outflows, suggesting that the two samples are not drawn from the same parent population. Finally, we additionally find that Mg II emission is preferentially detected in
galaxies with lower
stellar mass and $A_V$, and higher sSFR, consistent with conditions that favor the escape of resonantly scattered line and ionizing continuum radiation. We present the first evidence in $z\sim3$
star-forming
galaxies that properties of the absorption lines depend on
galaxy inclination, with more face-on systems showing stronger absorption and higher
outflow velocities, while inflowing gas is more frequently detected in more highly inclined
galaxies. These trends are consistent with observations at $z\lesssim1$ and predictions from cosmological simulations in which
galactic winds are launched perpendicular to the
galactic disks, while
accretion occurs primarily along the disk plane.
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All authors Emily Kehoe, Alice E. Shapley, Adam C. Carnall, Fergus Cullen, Thomas M. Stanton, Daniel Schaerer, Rui Marques-Chaves, Charles C. Steidel, Ryan L. Sanders, Natalie Lam, Karla Z. Arellano-Cordova, Ryan Begley, Sophia R. Flury, Natalia G. Guseva, Timothy Heckman, Alaina Henry, Akio K. Inoue, Yuri I. Izotov, Ho-Hin Leung, Derek J. McLeod, Kate Rowlands, Alberto Saldana-Lopez, Dirk Scholte, Maya Skarbinski, Struan D. Stevenson, Elizabeth Taylor, Bingjie Wang, Naveen A. Reddy
Quantum Physics
Multiple Topological Haldane Phases for Symmetry-Protected Quantum Information Processing
João Pedro Gama D'Elia, Irene D'Amico and Thereza Paiva
Symmetry-protected topological phases have attracted significant interest at the fundamental level and as a potential platform for
quantum information processing, owing to their protected edge states and resilience to perturbations. Applying these features for practical and efficient
quantum computation is highly desirable, but remains an open challenge. Here, we demonstrate the partitioning into multiple independent Haldane phase subsystems of a single
spin-1/2 ladder system and propose this as a scalable architecture for gate-based
quantum computation, which takes advantage of the
symmetry-protected topological order. We encode
qubits in the two topological states of the $S^{z}=0$ sector of each subsystem. Finite-size effects, typically viewed as detrimental, instead provide a controllable energy splitting that enables single-
qubit rotations using only local
magnetic fields. An Ising-type interaction between neighboring subsystem edges generates entangling gates, enabling universal
quantum computation driven by two control parameters that are easily accessible experimentally. Our results demonstrate how
symmetry-protected topological phases can be directly harnessed for
circuit-model
quantum computation in realistic systems.
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Quantum Physics
Supersymmetry of dissipative Bose-Fermi systems with application to Jaynes-Cummings and Dicke models
Colin V. Coane and Francesco Iachello
We demonstrate how supersymmetries of
Hamiltonians for coupled Bose-
Fermi systems can be used to place the
Hamiltonians of the Jaynes-Cummings model and Dicke model under the rotating wave approximation in
matrix form and provide explicit analytic solutions for their
eigenvalues. We then use this supersymmetry to place the Liouvillians of the associated Markovian open systems in
matrix form and provide explicit solutions for their
eigenvalues. These results are a consequence of the fact that the
Hamiltonian of the Jaynes-Cummings model commutes with the linear Casimir invariant of the superalgebra $u(1|1)$ and that the
Hamiltonian of the Dicke model commutes both with the linear invariant of $\sum_{i} u_{i}(1|1)$ and with the invariant of an additional $su(2)$
algebra. Our methods apply to various coupled Bose-
Fermi systems with $u(1|1)$ and more generally with $u(n|m)$ dynamical superalgebras, and may provide efficient tools for studying more complicated examples.
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Nuclear Theory
Analytic calculator for determination of $\gamma$-ray angular distribution coefficients and tensors in aligned and partially-aligned nuclei
A.M. Hurst, D.A. Matters and T. Kawano
A program has been developed to calculate a complete set of $\gamma$-ray angular distribution coefficients and statistical tensors in maximally- and partially-aligned
nuclei. For practical
nuclear structure and reaction purposes, there is no imposed constraint on any arguments that are likely to arise in the determination of these quantities. The program can also be used as a stand-alone vector-coupling calculator for the exact evaluation of Clebsch-Gordan and Racah coefficients, the closely-related Wigner 3-$j$, 6-$j$, and 9-$j$ symbols, as well as Gaunt coefficients. These quantities, which frequently arise in
quantum mechanical applications involving angular momentum coupling and recoupling schemes, provide the underlying machinery in angular distribution calculations.
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Mathematical Physics · Cross-listed from math.PR
Hindy Drillick and Levi Haunschmid-Sibitz
We introduce a censored version of the
stochastic six-vertex model. We show that for parameters $b_1 < b_2$, this model started from the initial condition ${1}_{x>0}$ is stochastically dominated at any time by the blocking measure. This is a partial analog of the censoring inequality for monotone
spin systems. In particular, this result allows us to control the behavior of second-class particles. The proof uses
parabolic Kazhdan–Lusztig $R$-
polynomials, whose appearance is explained using a connection between the
stochastic six-vertex model and the Iwahori–Hecke
algebras of symmetric groups. Furthermore, we find an intertwining relation for this process using normalized
parabolic Kazhdan–Lusztig $R$-
polynomials as an intertwining kernel.
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Astrophysics of Galaxies
The $M_{\rm BH}$$-$$R_{\rm b}$ relation and the high-mass end of the $M_{\rm BH}$$-$$\sigma$ relation
Bililign Dullo
Using a sample of 151
galaxies with dynamically measured black hole (BH) masses ($M_{\rm BH}$), we investigate the scaling relations between $M_{\rm BH}$ and the
stellar velocity dispersion, $\sigma$, and, for a subsample of 30 core-Sérsic
galaxies, between $M_{\rm BH}$ and the size of the partially depleted core, $R_{\rm b}$. Core-Sérsic
galaxies, identified using high-resolution $Hubble ~ Space ~ Telescope$ imaging and spanning both the normal-core $(R_{\rm b}<0.5$ kpc) and large-core ($R_{\rm b}>0.5$ kpc) regimes, define an updated $M_{\rm BH}$$-$$R_{\rm b}$ relation of the form $M_{\rm BH} \propto R_{\rm b}^{1.16 \pm 0.10}$, with an rms scatter of $\Delta_{\rm rms} \simeq 0.28$ dex in $\log M_{\rm BH}$. We find that Sérsic and normal-core
galaxies together follow a common log-linear $M_{\rm BH}$-$\sigma$ relation with a slope of $4.95 \pm 0.29$ and a scatter $\Delta_{\rm rms} \simeq 0.46$ dex. Deviations from this relation arise at the highest BH masses, where large-core
galaxies, including six with direct $M_{\rm BH}$ measurements, drive a significant upturn. We find that these
galaxies typically host ultramassive black holes whose masses scale more strongly with $R_{\rm b}$ than $\sigma$, and lie $\sim (1-4$) $~\times$ the intrinsic scatter (0.39 dex) above the relation defined by Sérsic and normal-core
galaxies. The $M_{\rm BH}$$-$$R_{\rm b}$ relation shows $\sim 30$-$47\%$ less scatter in $\log M_{\rm BH}$ than the corresponding $M_{\rm BH}$$-$$\sigma$ relation for the same sample. We interpret the high-mass upturn in the $M_{\rm BH}$$-$$\sigma$ diagram as a consequence of successive major, dry mergers, a scenario that naturally explains the observed flattening of the $\sigma-L_V$ relation at $M_V < -23.5$ mag.
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Astrophysics of Galaxies
The X-ray photon index Eddington ratio relation in radio-quiet quasars from XMM-Newton and SDSS
SH. M. Shehata, Baraa Hany and Reham Mostafa
This study presents a comprehensive X-ray spectroscopic analysis of 642
quasars, obtained by cross-matching the XMM-Newton Serendipitous Source Catalog (DR11) with the Sloan Digital Sky Survey (DR16)
quasar catalog. After stringent quality filtering and automated spectral reduction, we derived reliable
photon indices ($\Gamma$) and intrinsic 2–10 keV X-ray luminosities. Using multiwavelength data, sources were classified into 561
radio-quiet (RQ) and 81
radio-loud (RL)
quasars. We estimate the bolometric luminosity and Eddington ratio ($\lambda_{\mathrm{Edd}}$) from absorption-corrected X-ray measurements and virial black hole masses. Our primary objective is to establish and characterize the fundamental relationship between the
photon index and Eddington ratio for RQ population. We find that RQ
quasars exhibit systematically higher Eddington ratios, peaking at $\log \lambda_{\mathrm{Edd}} \approx -1.2$, and softer spectra with $\Gamma \approx 2.0$. A statistically significant positive correlation between $\Gamma$ and $\lambda_{\mathrm{Edd}}$ is detected in RQ
quasars, supporting disk–corona coupling models. To validate our results within the broader context of AGN
evolution, we further examine the dependence of $\lambda_{\mathrm{Edd}}$ on
redshift ($z$) and black hole mass ($M_{\mathrm{BH}}$). For RQ
quasars, $\lambda_{\mathrm{Edd}}$ increases with
redshift and decreases with $M_{\mathrm{BH}}$, in strong agreement with recent results \cite{aggarwal2024evidence}, highlighting the universal nature of these
accretion trends. By correlating spectral slope with
accretion rate, this work provides new insights into the interplay between
accretion physics, jet activity, and the
cosmic evolution of
quasars.
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Strongly Correlated Electrons
Hall conductivity reveals the nature of quantum coherence in strongly correlated metals
Emily Z. Zhang and Thomas P. Devereaux
Linear-in-temperature resistivity is a hallmark for strange metallic transport, and appears universally in many strongly correlated electron systems. However, the focus on the longitudinal channel often overshadows the profound microscopic insights contained within the transverse response. Here, we utilize numerically exact determinantal
quantum Monte Carlo simulations of the doped Hubbard model in a
magnetic field to calculate longitudinal and transverse transport. We demonstrate that while the resistivity is robustly $T$-linear across parameter sets, the
Hall response is highly sensitive to particle-hole asymmetry,
Fermi surface
topology, and many-body correlation effects. Specifically, the combination of these effects determine a crossover scale in which the system becomes
quantum-coherent, and is reflected in the
Hall conductivity. Our results demonstrate that while the $T$-linearity in resistivity appears universal, the
Hall response reveals a crossover from semi-classical to
quantum-coherent transport otherwise masked in the longitudinal channel.
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Solar and Stellar Astrophysics
Finding Novel Precursors for Solar Wind Stream Interaction Regions with Interpretable Deep Learning
Prateek Mayank, Yogesh, Enrico Camporeale et al. (+4 more)
Solar wind stream interaction regions (SIRs) drive recurrent geomagnetic storms, yet most existing catalogs rely on expert inspection and simple thresholds that are subjective and can miss events with complex morphologies. We present SIREN (SIR Encoder Network), a lightweight
Transformer based model for per timestep SIR detection from in situ
solar wind observations. The model ingests sequences of 11
solar wind parameters, spanning
magnetic field, velocity, and thermodynamic properties. With approximately 100,000 trainable parameters in a two layer encoder architecture, SIREN is trained using weighted binary cross
entropy loss and a cosine annealing learning rate. Platt scaling is applied to produce well-calibrated detection probabilities. On a held-out test set of 102 events, the calibrated model achieves a ROC-AUC of 0.93, F1 score of 0.78, and true skill statistic of 0.67. Analysis of the self-
attention weights confirms that the model concentrates on the SIR, grounding its decisions in the physically relevant portion of each sequence. Integrated Gradients attribution reveals a quantifiable feature hierarchy:
proton density (24.3%) and
magnetic field magnitude (21.6%) dominate, followed by temperature (13.9%) and bulk speed (12.1%). Notably, the transverse velocity component Vy and east-west flow angle together contribute 13-17%, identifying flow deflection as a consistent but previously under-quantified SIR signature. By producing continuous probabilities rather than binary labels, SIREN enables flexible threshold tuning for operational use and provides a template for compact, interpretable deep-learning systems in space weather.
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All authors Prateek Mayank, Yogesh, Enrico Camporeale, D. Chakrabarty, Lan K Jian, Gregory G. Howes, Thomas E. Berger
Instrumentation and Methods for Astrophysics
What I Wish I had Known When I Began Building Astronomical Instruments
Daniel Fabricant
This paper describes lessons learned over a long career building astronomical instruments. Although these lessons are based on one person's experiences, they were learned while working on major and minor instrument projects with many scientific and engineering colleagues. When I interact with colleagues entering the field, I am reminded that the "obvious" approaches were in fact learned over many years by observing others develop instruments, by receiving good advice, and by making mistakes. I hope to help others avoid making all of the same mistakes.
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