High Energy Physics (Phenomenology)
Papers
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Thursday 27 August
We investigate a $\mathbb{Z}_3$-symmetric extension of the Standard Model consisting of a right-handed neutrino ($N_R$), a dark fermion ($\chi$) that dominates the relic density and a dark complex scalar ($S$) that facilitates a strong first-order electroweak phase transition (SFOEWPT). The observed relic abundance, is achieved through the combined effects of annihilation, semi-annihilation, and dark-sector conversion processes over a broad region of parameter space consistent with a SFOEWPT. We further investigate the resulting multi-messenger signatures, including loop-induced direct detection, indirect detection through gamma-ray observations, and gravitational wave signals, with the latter lying within the projected sensitivities of future space-based detectors such as LISA, BBO, and DECIGO.
High Energy Astrophysical Phenomena
ANRe-M1: a GPU-accelerated numerical relativity code with multi-energy M1 neutrino transport
We present ANRe-M1 (Accelerated Numerical Relativity code with multi-energy M1 neutrino transport), a performance-portable, GPU-accelerated code for multidimensional core-collapse supernova simulations in full general relativity. ANRe-M1 builds on our original CPU-based Fortran framework and is implemented in C++ using Kokkos. It retains the underlying general-relativistic neutrino-radiation-hydrodynamics algorithms while redesigning the data layout, parallel decomposition, and memory-access patterns for accelerator-resident execution. The spacetime sector employs the BSSN–Z4c formulation and is coupled to relativistic hydrodynamics and energy-dependent M1 neutrino transport. We validate the implementation through a suite of hydrodynamic, radiation-transport, and dynamical-spacetime tests, together with comparisons to results from an earlier code-comparison study. We further demonstrate its applicability with a representative three-dimensional stellar-collapse computation including multi-energy neutrino transport. For the benchmark and computing systems considered here, ANRe-M1 runs approximately an order of magnitude faster on a cluster of AMD MI300A accelerated processing units than the Fortran version on a CPU cluster. When the allocation is increased from 2 to 128 MI300A APUs, the aggregate throughput rises by a factor of 39.7, corresponding to a weak-scaling efficiency of 62 per cent relative to the two-APU case. These results establish ANRe-M1 as an efficient and portable framework for long-term, multidimensional supernova simulations on current and forthcoming accelerator-based supercomputers.
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Optics
Visible Dielectric Metastructure for Generating Ultranarrow-band Perfect Absorption and Bound States in the Continuum
The ability to generate ultranarrow-band perfect absorption and bound states in the continuum (BICs) in the visible spectrum is highly useful and desired for many advanced optical and nanophotonic applications. However, achieving perfect absorption and BICs with a high quality-factor in the visible region remains challenging due to the material background absorption, radiative losses, and fabrication constraints. Here, we propose and demonstrate a dielectric nanophotonic platform that simultaneously achieves perfect absorption (99.0% at 603 nm) and multiple symmetry-protected BICs in the visible by integrating a dielectric metasurface with a distributed Bragg reflector (DBR). The coupling between the metasurface's localized dielectric resonances and the DBR-assisted photonic mode suppresses radiative leakage and enables ultranarrow-band resonances (full-width at half-maximum ~ 0.65 nm) with strong electromagnetic field (|E|) enhancement (up to 16.4 folds) within the DBR stopband. In addition, the metasurface's asymmetric design enables a magnetic multipole-assisted quasi-BIC resonance with polarization-dependent mode degeneracies, and the periodic structure enables Mie resonance-assisted multiple BICs. Furthermore, the tunability of design parameters provides additional degrees of freedom to control the resonances and their spectral positions. The coexistence of perfect narrowband absorption and BICs within a compact dielectric nanophotonic platform in the visible establishes a promising route toward next-generation low-loss, high-performance meta-optical devices and technologies.
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Materials Science
A solid-solution approach for room-temperature bulk plasticity in KTa1-xNbxO3
Dislocations are being engineered into perovskite oxides to harvest versatile functional properties. One major bottleneck, however, persists: perovskite oxides that can be engineered with dislocations, particularly via mechanical deformation at room temperature in bulk scale, have so far been limited to only three materials: SrTiO3 (2001, Brunner et al.), KNbO3 (2016, Mark et al.), and KTaO3 (2024, Fang & Zhang et al.). Here, we propose a simple and effective approach by using solid solution to significantly extend the range of materials. We showcase KTa1-xNbxO3 (0<x<1) perovskite oxides for their bulk plasticity at room temperature by constructing a closed-loop validation workflow that includes crystal growth, Brinell indentation, bulk compression, and transmission electron microscopy characterization. Our findings are expected to unlock the materials toolbox for dislocation-tuned functionality of perovskite oxides.
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Optics
Widely Tunable, Etch-free Multi-dielectric Fano Metasurfaces in the Visible
Fano resonances, characterized by a unique, sharp, and asymmetric spectral line shape arising from the interference between a narrowband discrete resonant state and a broadband continuum state, provide rich opportunities to control and manipulate light-matter interactions at the nanoscale. Here, we propose and demonstrate a nanophotonic architecture that integrates a multi-layered dielectric cavity into a one-dimensional grating to achieve an outstanding range of Fano resonance tunability by design, spanning 194 nm across the visible (from 500 to 694 nm), even with an ultra-thin layer of cavity (80 nm thick), offering the potential of highly compact photonic devices. The precise tailoring of the Fano spectral position through the adjustment of the cavity's structural parameters enables strongly localized field accumulation (at a maximum of 26 folds) within the cavity region. Additionally, the proposed architecture allows for bright and saturated structural colors in the visible, promising a route toward advanced digital display and printing technologies. Importantly, the experimental performance achieved with a simple, etch-free fabrication process results in a significant reduction in fabrication complexity and process-induced optical degradation. Our work showcases a robust platform for possible applications in Fano resonance-based low-loss nanolasers, on-chip photonic devices, optical communication components, and next-generation quantum technologies in the visible range.
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General Relativity and Quantum Cosmology
Relativistic Modeling for Solid Earth Tide Estimation via Space-to-Ground Clock Comparison
With the rapid development of modern atomic clock technology, their unprecedented precision elevates them from timekeeping tools to gravitational potential sensors, thereby fostering the highly interdisciplinary field of Relativistic Geodesy. Given the potential for high-precision clock networks to detect periodic gravitational variations, it is imperative to assess their capability to invert solid Earth tide parameters via space-to-ground links in the presence of complex observational noise. To this end, we incorporate Earth's gravitational potential, direct lunisolar tidal potentials, and solid Earth tide effects into a high-precision relativistic framework for space-to-ground clock comparisons. By employing a three-link Doppler cancellation configuration to isolate the target signal, we perform numerical simulations for an inclined geosynchronous orbit satellite to analyze the effects of clock instability and colored precise orbit determination errors on parameter extraction. Our findings reveal that while high orbital altitudes cause severe collinearity between individual Love numbers, an effective parameter combining the $h_2$ and $k_2$ Love numbers successfully converges to a stable estimate within a 30-day continuous observation window. Furthermore, sensitivity analysis demonstrates that extraction accuracy is currently limited by clock stability rather than radial precise orbit determination errors.
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High Energy Physics (Phenomenology)
Post-sphaleron conversion between baryon and lepton numbers
The conversion between baryon and lepton numbers has a significant impact on the mechanisms for dynamically generating the matter-antimatter asymmetry in the present universe. Under the traditional wisdom, such conversion originates from the so-called electroweak sphaleron processes. In this work we find that in association with a proper scalar and the other TeV new physics, the baryon-lepton conversion can still keep efficient after the electroweak sphalerons are no longer active. Moreover this scenario can provide a solution to the puzzle of neutron lifetime and predict some decay modes of multi-nucleons to multi-leptons.
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Cosmology and Nongalactic Astrophysics
ELUCID-DESI II. Revealing dark matter mass, tidal, and velocity (MTV) fields using galaxy group phase information
We introduce a novel method for reconstructing the cosmic mass, tidal, and velocity (MTV) fields over the redshift range $0 < z < 0.6$ using the phase information of galaxy groups. This approach replaces the explicit theoretical bias correction typically needed to relate galaxy groups to the underlying dark matter density field with a simulation-calibrated statistical mapping, reducing a major source of systematic uncertainty and making the method directly applicable to spectroscopic redshift surveys such as the DESI Bright Galaxy Survey (BGS). We evaluate the performance of our MTV reconstruction pipeline with mock redshift surveys that include a comprehensive set of observational selection effects. The galaxy groups used as tracers are identified with an extended halo-based group finder applied to the DESI mock galaxy catalogue with an apparent magnitude limit of $m_z < 19.65$, yielding a galaxy number comparable to that of the DESI BGS faint sample ($m_r < 20.175$). Our tests show that the reconstructed velocities are accurate and unbiased, with a residual dispersion of $\sim 120\ \mathrm{km\,s^{-1}}$ across the redshift bins. The recovered velocity field allows us to shift galaxy groups to their real-space positions, thereby correcting for the Kaiser effect. By iteratively applying this Kaiser correction to the galaxy groups, we further reconstruct the tidal field and the mass-density distribution. The reconstruction is stable with respect to the grid resolution. Overall, our results demonstrate that this group-based phase-space reconstruction provides a robust pathway to recovering the dark matter MTV fields, with strong prospects for application to DESI BGS data.
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High Energy Astrophysical Phenomena
Optical Discovery of New and Candidate Galactic Supernova Remnants Plus Optical Imaging of the Monogem Supernova Remnant
We report the discovery of new and candidate Galactic supernova remnants made through over 2000 hours of H$\alpha$ and [O III] imaging using amateur class instrumentation. These nebulae range from 0.5 to over 8 degrees in size. Five of these, namely G27.8-17.1, G115.6+9.2, G190.5+25.3, G195.9+2.2 and G239.9+7.0 exhibit low-dispersion optical spectra indicating shock emission by the presence of strong [S II] $\lambda\lambda$6716,6731 and [O I] $\lambda$6300 line emissions relative to H$\alpha$, or exhibit a nonradiative shock generated Balmer dominated spectrum. Their filamentary emission morphology also supports the presence of interstellar shock fronts. Three other optical nebulae, G191.3+11.1, G205.7-1.7, and G305.4-0.7 appear likely to be remnants and are proposed as new SNR candidates. We also present [O III] and H$\alpha$ images of optical filaments associated with the 25 degree diameter Monogem Ring SNR which reveal extensive emission-line filaments around most of the remnant's X-ray boundaries. Deep images of the X-ray suspected remnant G190.4+12.5 and the large and [O III] emission dominated SNR G206.6+6.1 seen toward or near the Monogem SNR are also included. Key findings of this work include: 1) optical surveys can sometimes detect SNRs better than radio and X-ray SNR searches, 2) Balmer nonradiative shocks appear not uncommon in high Galactic latitude SNRs, and 3) faint Ø3 emission dominated SNRs may have been missed in prior H$\alpha$ emission only surveys.
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High Energy Astrophysical Phenomena
Spectro-Polarimetric Properties of CHIME FRB Sources
Fast radio bursts (FRBs) are enigmatic millisecond-duration radio transients whose polarization properties offer crucial insights into their origins and environments. In particular, low-frequency depolarization—quantified by the parameter \(\sigma_{\mathrm{RM}}\)—probes the complex magneto-ionic medium surrounding the progenitor, and has been observed across a population of repeating FRBs. We present a systematic spectro-polarimetric analysis of repeating and non-repeating FRBs using observations from the Canadian Hydrogen Intensity Mapping Experiment (CHIME). For 28 repeating FRBs, we measure \(\sigma_{\mathrm{RM}}\), expanding the known sample from 14 to 36 sources (an increase by a factor of 2.6). The kernel density estimate (KDE) of the repeating population peaks at \(1.3\ \mathrm{rad\,m^{-2}}\), with approximately 70% of the sources showing \(\sigma_{\mathrm{RM}} \gtrsim 1\ \mathrm{rad\,m^{-2}}\), implying that most reside in complex magneto-ionic environments. For 70 non-repeating FRBs, we investigate four spectro-polarimetric models; no source exhibits significant depolarization with \(\sigma_{\mathrm{RM}} \gtrsim 5\ \mathrm{rad\,m^{-2}}\). Roughly half of the non-repeaters are consistent with a constant linear polarization fraction across frequency. We caution, however, that these results may be affected by the limited frequency coverage of CHIME. Future ultra-wideband polarimetry, spanning widely separated frequencies, will overcome current observational biases, enable precise \(\sigma_{\mathrm{RM}}\) measurements, and substantially deepen our understanding of FRB environments.
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Superconductivity
Strain-driven orbital-selective reconstruction and bicollinear-to-stripe evolution in FeTe
FeTe, as a representative parent material among iron-based superconductors, provides an ideal platform for exploring the interplay among orbital-selective correlations, magnetism, and unconventional superconductivity. However, a unified picture of the correlated electronic structure and magnetism of FeTe under strain remains to be fully clarified. Here, combining density functional theory plus dynamical mean-field theory and Heisenberg model analysis, we uncover an orbital-selective reconstruction of the correlated electronic structure and reveal a strain-driven trajectory from bicollinear to stripe antiferromagnetism (AFM) via an intermediate competing staggered $n$-mer AFM regime in FeTe. Moderate strain gives rise to a regime where more coherent quasiparticles coexist with suppressed local moments. Further strain drives FeTe into an incoherent correlated regime with robust local moments and Fe-$3d_{z^2}$-dominated low-energy states. These results establish a strain-driven trajectory across distinct magnetic and correlated electronic states in FeTe.
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Quantum Physics
A thermometric quantum Brownian model for low-temperature electronics
Quantum mechanical models of resistors in quantum electronics are often based on the quantum optical master equation (QOME). The QOME overlooks several fundamental properties, limiting its ability to model certain superconducting phenomena. Here we present a thermometric model of resistors, adapted from the quantum Brownian motion equation (QBME), that facilitates practical use of the QBME in modelling dissipative electronics at low temperatures. We compare the thermometric QBME presented here with predictions of the QOME, in the simple example of a transmon shunted by a resistor. We show that both the QBME and QOME yield comparable but physically distinct predictions, and discuss potential experimental tests with which to discriminate their use in modelling practical experiments.
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Quantum Gases
Emptiness formation in the Lieb-Liniger gas: hydrodynamic instantons and a conjectured rate function
We study the emptiness formation probability (EFP) in the ground state of the repulsive one-dimensional Lieb-Liniger Bose gas. For a macroscopic empty interval of length $2R$, its leading asymptotic behavior is described by a rate function $f(\gamma_0)$, defined by $-\log P(R)\sim(\rho_0R)^2f(\gamma_0)$, where $\rho_0$ is the mean density and $\gamma_0$ is the dimensionless interaction strength. We propose a parameter-free integral equation for $f(\gamma_0)$. Starting from the exact dual-field Fredholm-determinant representation of the EFP, we show how the conjectured kernel arises formally and identify the uniform asymptotic statement that remains to be proven for a rigorous derivation. The conjecture reproduces the Tonks-Girardeau and weak-coupling limits, as well as the first correction obtained independently in both limits. It also agrees at the few-percent level with numerical minimization of the Lieb-Liniger hydrodynamic action over more than four orders of magnitude in coupling. The numerical calculation yields the corresponding emptiness instantons and their astroid-like vacuum regions.
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Fluid Dynamics
Z-Fold Wing Aeroelasticity: Compositional Modeling, 1:2 Double-Hopf Dynamics, and Nonlinear Stiffness Effects
Folding changes the linearized aeroelastic spectrum and can switch which mode becomes unstable first, with consequences for local postflutter interactions. This study formulates a three-component Z-fold wing by assigning every aerodynamic station to a structural component and a material coordinate. The same attachment map generates surface motion and returns pressure loads through virtual work. Geometrically exact component dynamics, an explicit-wake unsteady vortex-lattice model, and block-structured descriptor assembly preserve the physical paths of configuration actions. A two-parameter flutter analysis shows that a smooth flutter-speed envelope conceals a high-low-high sequence of controlling neutral branches, expressed as a critical-frequency valley and a redistribution of component deformation. Numerical continuation locates a near-1:2 double-Hopf point. Within a local model retaining quadratic and cubic structural restoring forces with aerodynamic and inertial operators fixed at the scheduling point, the cubic normal form captures selected 26-state observations and admits high-frequency-dominant and mixed phase-locked periodic solutions. The formulation links configuration-dependent flutter-mode identity to local resonant dynamics and supports blockwise sensitivity and design reasoning.
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Quantum Physics
Quantum estimation theory with quantum noise control
Quantum estimation theory serves as one of fundamental backbones of quantum Shannon information theory and was mathematically systematized by pioneers of quantum information science. Although its applied research saw limited progress for a long period, the 21st century has witnessed active discussions and numerous fruitful proposals regarding its applications. Notably, the contributions of Monras and Paris represent one of the most remarkable achievements addressing the realization problem of estimation bounds. This paper aims to demonstrate a practical direction for extending their original ideas. Next-generation quantum information mechanisms urgently demand guarantees of quantum advantage unattainable by classical theory, alongside strict real-time processing without delays. By leveraging the concept of generalized heterodyne detection proposed nearly half a century ago, we demonstrate that a scheme based on their results can effectively meet the stringent requirements of near-future information technologies.
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Optics
Lower bound on the thickness of broadband dielectric mirrors
We present a lower bound on the total physical thickness of a lossless, non-dispersive dielectric mirror for a given minimum reflectance across a wavelength band. The bound is based on a causality-based sum rule translated from a known result in acoustics, that expresses the wavelength integral of the logarithmic transmission of any lossless one-dimensional refractive-index profile as a function of the total thickness of each material comprising the profile, independent of how the layers are arranged. Calculating the thickness bound for a dielectric mirror, given some incident medium and substrate, requires only the lowest and highest refractive indices used in the thin-film stack and the minimum desired reflectance for a given wavelength span. We find that (1) the bound is set by the wavelength span so, for example, a 400-700 nm and an 800-1100 nm mirror have the same bound; (2) the figure of merit for materials minimizing the necessary thickness is $(n_H-n_L)^2/(n_H+n_L)$, where $n_H$ and $n_L$ are the indices of the high- and low-index materials; and (3) each additional "nine" of reflectance (e.g., from 99% to 99.9%) requirement adds a fixed amount of additional thickness to the bound. Non-exhaustive numerical calculations show that the readily achievable thickness is about twice our bound.
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Quantum Physics
Quantum-enhanced single and multiparameter metrology in qutrit ensembles by generalized twisting dynamics
Quantum-enhanced sensing with atomic ensembles has predominantly focused on qubit-based protocols, despite the growing ability of many experimental platforms to coherently control and entangle multi-level systems. Here, we investigate quantum-enhanced sensing with qutrit ensembles by introducing three experimentally feasible qutrit generalisations of the one-axis twisting (OAT) model that involve entangling operations only between two levels, while the third level primarily acts as a spectator. We characterize the metrological utility of the dynamically generated states using the quantum Fisher information toolbox. We find numerically that all three models offer considerable freedom in encoding direction for quantum-enhanced sensing, with up to 6 out of 8 possible directions exhibit near-Heisenberg scaling after a short evolution time. We discuss experimental access to this enhanced metrological precision via effective time-reversal protocols. Furthermore, we examine the practical issues of estimation ambiguity and local dissipation, and show that they can be largely overcome by optimizing the sensor operating point. Finally, we show that the measurement incompatibility in estimating multiple parameters simultaneously encoded in different directions with near-Heisenberg scaling of precision is suppressed at the zero operating point as the system size increases. In the process, we find that one of the models enables near-Heisenberg scaling metrology with a pair of commuting generators, a possibility that arises from the $su(3)$ algebra and is thus absent in qubit-ensemble based sensors of collective $SU(2)$ rotations.
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Solar and Stellar Astrophysics
Bifrost spectral inversions: Fast non-LTE solar chromospheric diagnostics from 3D simulations
Modern solar observatories produce vast amounts of detailed spectral data. To infer atmospheric parameters from these data, in particular for the solar chromosphere, requires immense computational resources. This problem is becoming more acute as spatial resolution improves, and faster methods are much needed to make sense of the data. Archive-based inversions provide a cost-effective way to infer atmospheric parameters from solar spectra; they involve building databases of synthetic spectra and atmospheric models. We extended this idea to a k-nearest neighbour inversion with non-LTE chromospheric spectra from a 3D radiative-magnetohydrodynamic simulation. Our database consists of 150 million Ca II 8542 Å line profiles from a magnetically quiet simulation. We validated our method on a different simulation and then applied the database inversion to high-cadence observations taken with the Swedish 1-m Solar Telescope. We find excellent agreement between the observed and fitted spectra for almost the entire field of view. We recovered the chromospheric temperature and line-of-sight velocity and calculated the uncertainty in their inversions. The gas temperature has small uncertainties over a broad range of optical depths, and we recover a physically consistent solution, even beyond the line sensitivity region. Compared with the traditional inversion method, our approach is four orders of magnitude faster. Limitations and future improvements of the method are discussed.
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High Energy Astrophysical Phenomena
Investigating the disappearance of a type-C QPO in black hole X-ray binary Swift J151857-572147 with AstroSat
We present a timing and broadband spectral study of the AstroSat observation of the black hole low mass X-ray binary Swift J151857.0–572147, focusing on its evolution across two temporal segments, S1 and S2. During the first segment S1 lasting $\sim$ 50.6 ks, the source shows a clear type-C QPO at $\sim8.02$ Hz and a low-frequency bump (LFB) in the power density spectrum. By the later segment S2, the strength of the QPO feature decreases significantly and is no longer consistent with a coherent QPO, along with the simultaneous disappearance of the LFB. An energy-dependent analysis reveals that both the RMS amplitude and the time lag of the QPO in S1 increase monotonically with energy, suggesting a low inclination nature of the source. The QPO and LFB centroid frequencies show a strong positive correlation across orbital segments, with a Pearson coefficient of 0.98. Our variability analysis and hardness-intensity diagram reveal a spectral state transition of the source coincident with the turn-off of the QPO and the LFB, a conclusion supported by the evolution of broadband spectral parameters. Notably, the orbit-resolved spectral analysis reveals that the non-thermal parameters, photon index, and electron temperature of the corona exhibit significant deviation as the source traverses from S1 to S2, whereas the thermal parameters scatter without any systematic variation between the two segments. The simultaneous turn-off of the type-C QPO and the low-frequency broadband noise component, both originating from the hot inner flow, indicates a rapid reorganization of the inner accretion geometry. Our results strongly suggest a coronal origin for the QPO and demonstrate that the disappearance of both features reflects a substantial transformation of the Comptonizing region across the spectral transition.
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Statistical Mechanics
When dissipative steady states admit thermodynamic occupation laws
Non-equilibrium steady states (NESSs) generally lack thermodynamic occupation laws because finite stationary circulation and a globally exact rate-ratio field cannot coexist for the same Markov generator. Here we construct a sector-separated geometry that overcomes this incompatibility without arresting dissipation. Entropy-production exposure-and-separation excludes the entropy-producing state~$0$ from the conditional occupation manifold while retaining it in the dissipative full graph; physical returns $i\to0\to0^\ast$ become effectively Markovian in the strong-bias/rapid-reset (SR) limit. For a thermodynamically complete conditional manifold, autonomous redistribution (AR) eliminates residual futile circulation, making the rate-ratio one-form exact. Thermodynamic calibration gives $X_i=\beta(\Delta\mu- \mathcal F_i^{\mathrm{cost}})$ and $p_i=e^{X_i}/Z_\mathcal{C}$, with $Z_\mathcal{C}=1+\sum_i e^{X_i}$. Full-graph probabilities factorize exactly as $P_\alpha=(1-P_0)p_\alpha$. In the SR limit, the kinetic factor tends to unity while $p_\alpha\to e^{X_\alpha}/Z_\mathcal C$, yielding $P_\alpha\to p_\alpha$ while finite dissipation persists. Near AR, integrability is lost linearly in residual cycle current whereas dissipation begins quadratically. In the binary zero-cycle-rank limit, occupation redistributes autonomously under maintained $\Delta\mu$ bias, yielding the inverted Fermi–Dirac law, which is applied to thermal smearing in quantum-dot lasers. The framework provides constructive acquisition conditions and failure diagnostics for thermodynamic occupation laws in dissipative NESSs.
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Soft Condensed Matter
Influence of twist direction and large deformation on soft material torsional contact
Shear-induced contact area reduction is widely observed in soft contacts, yet recent torsional experiments have revealed a more complex non-monotonic evolution in which the contact area first increases and then decreases with twist angle. The mechanism responsible for this initial area increase and the role of large deformation in the overall area evolution remain unclear. In this study, we experimentally investigate the torsional contact response of soft Polydimethylsiloxane (PDMS) spheres by combining forward-backward twist tests with a systematic variation of the curing-agent-to-base ratio to tune material softness and deformation level. The loading-unloading tests show that the torsional interface is strongly irreversible: during unloading, the contact area follows a decrease-increase-decrease path rather than retracing the loading branch, and repeatable petal-like edges appear, indicating a wrinkle-induced surface instability. By decreasing the mixing ratio, we find that larger deformation strengthens the area-reduction contribution and eventually suppresses the initial area increase, leading to a monotonic area decrease during loading for sufficiently soft PDMS. Softer PDMS also exhibits lower shear strength, weaker torque oscillations, and improved repeatability. The results provide experimental evidence that large deformation can drive shear-induced contact area reduction, while the origin of the initial area increase remains unresolved. These findings narrow the possible mechanisms (e.g., triboelectrification) responsible for the initial area increase and provide a stringent benchmark for frictional contact models of soft interfaces.
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Fluid Dynamics
Resolvent analysis to inform viscoelastic coatings for turbulent drag reduction
Viscoelastic compliant coatings offer a passive route to modify wall-bounded turbulence; however, their effectiveness for drag reduction remains unresolved. We perform resolvent analysis of turbulent boundary layers over linear viscoelastic continuum, and apply it to incompressible hydrodynamic and compressible aerodynamic zero-pressure-gradient turbulent boundary layers, using both standard and eddy viscosity resolvent formulations. Across a wide range of storage modulus E and coating thickness H, viscoelastic surfaces amplify near-wall-cycle-type modes while also attenuating the resolvent gain of very large scale motions (VLSMs) by up to 50%, which together result in a reduction of Reynolds stress. For density-matched coatings representative of aqueous incompressible flows, however, these favorable bands lie entirely within the regime where the effective coatings are linearly unstable to traveling wave flutter, rendering them practically unrealizable. Optimizing material damping does not eliminate this but provides a pathway to use weaker sub-optimal interactions. In supersonic flow, the large solid-to-fluid density ratio (O(1000)) shifts the favorable interaction to substantially higher moduli, weakening the achievable reduction in turbulence production to a few percent. However, the strongest interaction band occurs in the linearly stable regime. These results suggest that compliant wall drag reduction via coupling with high gain modes is fundamentally constrained by flow-induced structural instabilities in incompressible applications, whereas the high density ratios of supersonic flow offer a much narrower but stable window for practical coatings.
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Strongly Correlated Electrons
Thermally quenched metastability in metal-insulator transitions via elemental substitution
Thermal quenching inhibits equilibration toward the thermodynamic ground state during phase transitions, revealing metastable phases such as structural glasses and quenched alloys. Whether such thermally quenched metastability can be realized in metal-insulator transitions has remained an open question because these transformations are governed by collective electronic reorganization rather than atomic diffusion. We demonstrate that rapid cooling exceeding 10$^9$ K s$^{-1}$ kinetically avoids the metal-insulator transition, stabilizing a long-lived metastable metallic phase in tungsten-substituted VO$_2$. Temperature-dependent relaxation reveals nucleation-dominated kinetics with a thermal activation barrier introduced by tungsten substitution. Our results establish elemental substitution as a route to thermally quenched metastability in metal-insulator transitions, expanding metastable phase control to electronic phases.
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High Energy Physics (Phenomenology)
Fermi gas of domain-wall Skyrmions in QCD in a strong magnetic field
Fermionic domain-wall Skyrmions arise in the chiral soliton lattice of two flavor chiral perturbation theory in a magnetic field as the ground state and are associated with baryons of the underlying theory of quantum chromodynamics. We analyze the electromagnetic screening characteristics of domain-wall Skyrmions that give insight into baryon density on the magnetic field and chemical potential phase diagram. At zero temperature, using the moduli effective theory, it is found Skyrmion density is saturated up to the Fermi momenta on the disk of the chiral soliton lattice orthogonal to the magnetic field. We further study chiral perturbation theory coupled to quantum electrodynamics leading to finite temperature screening, wherein a static fermionic domain-wall Skyrmion screening is predicted through a combined Debye mass/length.
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Quantum Physics
Auditing Structured Randomness for Quantum Error Correction under a Bounded Cloud Fault Model
Cloud quantum processors compile submitted quantum error correction circuits and may colocate them with untrusted workloads. A fixed public encoder gives a fault-injection adversary a reusable target. Per-run reseeding changes the physical-to-logical fault map. Exact Haar-random encoders have exponential circuit cost. Efficient random ensembles provide average-moment guarantees and leave worst-case accepted corruption uncharacterized. We define accepted logical disturbance, an acceptance-weighted measure of harmful logical action in accepted results, and derive its exact Haar expectation. We evaluate a polynomial-cost seeded Clifford encoder family using dense linear algebra and gate-level stabilizer simulation against faults chosen before or after the encoder is known. Reseeding reduces mean accepted logical disturbance from 0.150 for faults chosen after learning each encoder to 0.020 for one fault chosen before it is known. The 86.7% reduction results from rejection. The fixed distance-three \([[5,1,3]]\) code corrects every tested weight-one Pauli, while 18.5% of sampled encoders in the selected ensemble satisfy exact quantum error correction. The measured reduction quantifies the integrity gain from reseeding and separates postselected detection from exact correction under explicit fault and attacker-knowledge models.
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Mathematical Physics
The Sharp Spectral Transition for Almost Mathieu Operators via Alternating Resonances
We prove that for any given frequency resonance exponent and phase resonance exponent, there exist a frequency and a phase exactly realizing these values such that the Almost Mathieu operator exhibits Anderson localization for $\ln|\lambda|>\max\{\beta(\alpha),\delta(\alpha,\theta)\}$. This resolves the conjecture in \cite{MR4686650}.
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Materials Science
Atomic investigations on the mechanical properties of CoCrNi medium-entropy alloy nanowires
This work investigated the mechanical properties of CoCrNi medium-entropy alloy (MEA) nanowires under uniaxial tensile loading along three crystallographic orientations [100], [110] and [111]. The face-centered cubic (FCC) single-crystal CoCrNi nanowires exhibit pronounced anisotropy Molecular dynamics simulations were employed to provide atomic-level insights into the plastic deformation mechanism. The surface effect causes dislocations to nucleate at the free surface and slip inward. The temperature effect was also considered. Under identical geometric configurations, crystal orientations, and temperatures, interatomic interactions govern key mechanical properties such as Young's modulus and yield strength. Simulation results reveal a strong linear correlation between the average atomic force and mechanical performance across eight representative FCC metallic nanowires (Al, Au, Ag, Cu, Ni, Al19Mg alloy, FeCoCrCuNi high-entropy alloy (HEA), and CoCrNi MEA). This study delivers novel insights into the mechanical behavior of metallic nanowires and offers guidance for the rational design of alloy nanowires.
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Cosmology and Nongalactic Astrophysics
Approximating the peculiar velocity distribution of dark matter halos with Tsallis statistics
Dark matter halos, which host galaxies and galaxy clusters, have peculiar velocities far from thermal equilibrium. Characterizing the nonlinear and non-Gaussian features of this velocity distribution improves our understanding of the gravitational evolution of the cosmic web and supports related cosmological applications. We endeavor to establish a connection between the peculiar velocity distribution of halos and nonequilibrium statistical mechanics, with the objective of obtaining a model that is both concise and accurate for practical applications. We extracted halo samples from large N-body simulations and performed maximum-likelihood fits to the peculiar velocity distributions using a two-parameter Tsallis model, derived from non-extensive statistical mechanics. On the theoretical side, we reformulated the halo distribution in the superstatistics framework by means of a generalized Gram-Charlier expansion based on the gamma distribution. For halo peculiar velocities below 1000 km/s, the Tsallis model achieves 5 percent accuracy over z=0-2, with performance improving toward lower redshifts. Our results show that the halo velocity distribution becomes increasingly non-Gaussian and departs further from equilibrium over time. The best-fit parameters depend only weakly on mass, though low-mass halos exhibit slightly stronger non-Gaussianity. The two parameters, especially the velocity dispersion, offer promising probes of cosmological parameters. Theoretically, we find that in general the halo peculiar velocity distribution function is expressible as a superposition of a series of Tsallis distribution functions, while simulation results demonstrate that the zeroth-order approximation, namely a single Tsallis function, already achieves sufficient accuracy.
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Nuclear Theory
Ancilla-recycled RODEO filtering for nuclear scattering: A cross-platform benchmark on quantum processors
Quantum computation of trapped spectra for nuclear scattering requires resource-efficient circuits and reliable energy inputs. We present a cross-platform benchmark of ancilla-recycled RODEO filtering for a four-dimensional effective Hamiltonian describing a trapped neutron–proton model. Static circuits on IonQ Forte-1 and dynamic circuits on IBM Aachen implement the same ideal ten-cycle all-zero accepted filter using twelve and three active qubits, respectively. Mid-circuit measurement and reset reduce the active qubit count by 75% while retaining all controlled evolutions. The interleaved IBM peak-center offset from the exact level is $-0.017 \pm 0.507~\mathrm{keV}$, compared with $-0.568 \pm 0.694~\mathrm{keV}$ for IonQ (finite-shot bootstrap uncertainties). At \(\omega=3.7~\mathrm{MeV}\), the modified effective range expansion maps both centers to finite-confinement scattering inputs consistent with the exact reference within propagated uncertainties. Three IBM batches exhibit center variations beyond finite-shot uncertainties (\(p=0.015\)), despite comparatively stable postselection amplitudes. Calibration-derived noisy simulations do not consistently reproduce the measured centers. Complete sampled support enables sample-based quantum diagonalization to recover the exact effective-space level, whereas larger-space simulator tests expose substantial errors from omitted configurations. The calculation validates one finite-confinement input, not a free-space phase shift. This benchmark provides a reusable circuit and validation protocol separating spectral precision, hardware repeatability, and sampled-subspace completeness for multilevel nuclear-scattering calculations.
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High Energy Astrophysical Phenomena
FRB 121102: No supernova-like ejecta or magnetar power, hinting at a binary WD merger
We use measurements of the time-dependent dispersion measure of the repeating FRB 121102, together with earlier radio observations of its associated persistent radio source (PRS), to derive stringent constraints on its underlying “engine.” The energy held by the relativistic PRS plasma is $>10^{49.5}$ erg, and its age is $\approx60$ yr, corresponding to an underlying source power exceeding $10^{40}$ erg s$^{-1}$. If the underlying source is a neutron star, this implies a rotational rather than a magnetic energy source, consistent with a $\sim10$ ms, $\sim10^{12.5}$ G neutron star. Alternatively, accretion may also be a viable energy source. The velocity and the kinetic energy of the cold plasma confining the relativistic PRS plasma are inconsistent with it being typical supernova ejecta (unless a significant fraction of the ejecta mass is carried by high-density clumps of $\approx10^{-2.5}$ fractional size)- its expansion speed is limited to a few hundred km/s, which also implies that it was ejected from the source more than $\approx 10^3$ yr preceding the onset of relativistic PRS plasma emission. These constraints may be satisfied by a white dwarf binary merger progenitor system, where a fraction of a solar mass was ejected at a slow speed during and after the merger, and a rapidly rotating neutron star was formed after $\sim10^3$ yr thermal evolution period of the merger remnant.