High Energy Physics (Phenomenology)
Chan-Gyung Park, Dahee Lee, Hyerim Noh et al. (+1 more)
A pronounced pyramid-shaped enhancement in the
axion density power spectrum induced by the QCD phase transition is identified. The enhancement occurs near the horizon scale at the transition, with a characteristic comoving length scale comparable to the size of the
Solar System, and amplifies the
axion density perturbation by factors exceeding $3.5 \times 10^{13}$ relative to the CDM case. Under the hilltop initial condition, coupling to radiation triggers this enhancement. The initial condition is related to the
axion mass, suggesting that observation of the
axion pyramid in cosmology may constrain the QCD
axion mass.
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All authors Chan-Gyung Park, Dahee Lee, Hyerim Noh, Jai-chan Hwang
Earth and Planetary Astrophysics
HD 715 b, a Warm Jupiter Orbiting a Massive Subgiant Discovered from a Single TESS Transit
Alexander Venner, Robert A. Wittenmyer, Andrew Vanderburg et al. (+23 more)
Transiting Warm Jupiters orbiting bright
stars are scarcely known, but a substantial number of these
planets have been uncovered by the TESS mission. In this work we report the discovery and confirmation of a transiting Warm Jupiter orbiting the bright ($V$ = 8.70) subgiant
star HD 715 (TOI-6893). HD 715 b was originally identified from a single transit event in TESS Sector 70. We acquired two seasons of radial velocity follow-up using the PFS, TRES, and MINERVA-Australis spectrographs, which clearly detect the planetary orbit. At $M_*=1.60\pm0.04 M_\odot$, HD 715 thus becomes one of the most massive
stars known to host a transiting Warm Jupiter. From a joint fit to the TESS transit and our RVs, we find that HD 715 b has a $56.40^{+0.19}_{-0.23}$ day orbital period and measure a precise mass and radius of $0.635\pm0.056 M_J$ and $1.07\pm0.04 R_J$, rendering it a relatively typical member of the Warm Jupiter population. The moderate orbital eccentricity of $0.21^{+0.07}_{-0.08}$ contrasts with the higher eccentricities of other similar Warm Jupiters orbiting evolved
stars, indicating a greater diversity in orbital eccentricities than previously known. The absence of additional transits in preceding TESS observations in Sectors 42 and 43 allows us to further refine the range of possible orbital periods to $[56.01, 56.35]$ days. Though the ephemeris uncertainty remains substantial, future photometric observations may nonetheless allow for recovery of the transit of HD 715 b.
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All authors Alexander Venner, Robert A. Wittenmyer, Andrew Vanderburg, Karen A. Collins, David W. Latham, Allyson Bieryla, Tyler R. Fairnington, Chelsea X. Huang, Timothy R. Bedding, Samuel Grunblatt, Sydney Jenkins, R. Paul Butler, Jeffrey D. Crane, Jhon Yana Galarza, Jonathan Horner, Steve B. Howell, Marc Huten, Stephen R. Kane, David Osip, Marcelo Said Tala Pinto, Samuel N. Quinn, Johanna Teske, Steve Shectman, Shreyas Vissapragada, Duncan Wright, George Zhou
Quantum Physics
Total Ordering of Resources: A Quantum-Classical Separation
Jingsong Ao, Julio I. de Vicente and Alexander Streltsov
A central goal in
quantum information science is understanding which physical states can be converted into others. The ideal scenario would be a totally ordered system, where every state can be ranked by a single value, and a higher-ranked state can always be converted into a lower-ranked one. Such an ordering would provide a complete description of state convertibility, making the resource structure maximally simple to characterize and compare. We prove that such a simple ordering is fundamentally impossible for any
quantum system with dimension larger than 2. The underlying properties of
quantum mechanics guarantee that some states will always be incomparable. Furthermore, we show this is a uniquely
quantum phenomenon by constructing classical systems of any size that can be perfectly ranked. This establishes a rigorous and striking divide between
quantum and classical state transformations.
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Medical Physics
Gold nanorod radioenhancement: interpreting Monte Carlo dose enhancement across geometry, composition, coating, and localization
Ali Taheri, Hans Rabus, Mayeen Uddin Khandaker et al. (+2 more)
Nanoparticle radiosensitization depends on interconnected NP properties, yet geometry, elemental composition, surface coating, and localization are typically studied separately, with their combined biological impact rarely assessed in one framework. Drawing on TOPAS Monte Carlo simulations from PhD research, we consolidated four investigations of metallic nanorods, mainly gold nanorods (AuNRs), examining these parameters across closely linked studies. The findings reveal that each parameter can influence over a distinct spatial range. Nanorod geometry primarily alters the spectrum and distribution of low-energy Auger-Meitner electrons emitted within tens of nanometers. Elemental composition induces significant near-field dose enhancement that rapidly attenuates and becomes negligible beyond roughly 1 um. Surface coatings reduce the fluence of secondary electrons below 3.5 keV, absorbed within about 150 nm of the surface, lowering physical dose contribution by 1-7%. Since coatings predominantly remove low-energy electrons, radiolytic yield changes through a shift in the electron energy spectrum, not directly following dose response. At the vascular scale, the enhanced dose region extends to approximately 10 um from the vessel wall, meaning NP localization determines where the biological target sits relative to radiation sources. Collectively, no single design parameter serves as a universal predictor of radiosensitization. Translating physical radioenhancement into biological effect depends on whether the target lies within each parameter's effective range. Furthermore, charged-particle
equilibrium (CPE) correction, applied where beam confinement necessitated it, substantially alters calculated dose enhancement ratios. Consequently, scoring distance and CPE-corrected values should be explicitly reported to ensure comparability across studies.
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All authors Ali Taheri, Hans Rabus, Mayeen Uddin Khandaker, Farhad Moradi, David Andrew Bradley
High Energy Physics (Experiment)
HybridMC: a fast detailed simulation framework for optical calorimeter technologies at the LHCb ECAL Upgrade II
Marco Pizzichemi, Liupan An, Federico Betti et al. (+5 more)
The detailed Monte Carlo simulation of optical calorimeters is dominated by the generation and tracking of scintillation and Cherenkov
photons, which in standard Geant4 ray-tracing increases the CPU time per electromagnetic shower by up to three orders of magnitude compared to simulating only the energy deposition. At the luminosity and granularity foreseen for the LHCb ECAL Upgrade II, this cost becomes prohibitive for both detector R&D and large-scale sample production. The optical
photons cannot simply be discarded, because the time resolution of a few tens of picoseconds targeted by the upgrade to mitigate pile-up is driven by their arrival-time distribution at the photo-detectors. This paper presents HybridMC, a fast and detailed simulation framework for optical calorimeters that decouples shower development from optical transport. Energy deposition is handled by a standard Geant4 simulation without optical
photon propagation, while light transport is reproduced by a parametrised summary Monte Carlo step based on probability density functions extracted from a one-time full ray-tracing optical calibration. A Monte Carlo-to-Monte Carlo validation shows good statistical agreement with full ray-tracing for all module types of the upgraded LHCb ECAL, from individual
photon arrival times up to the reconstructed energy and time resolutions. The CPU time is reduced by more than two orders of magnitude, with module-dependent acceleration factors from 150 to 480. A comparison to test-beam data from DESY II and the CERN SPS shows that the framework reproduces the momentum dependence of the measured energy and time resolutions of a real prototype, up to a small residual constant term. HybridMC retains the microscopic optical detail not accessible to flash simulators based on generative models, at a CPU cost compatible with large-scale production on standard computing infrastructure.
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All authors Marco Pizzichemi, Liupan An, Federico Betti, Aleksandar Bordelius, Loris Martinazzoli, Philipp Roloff, Matteo Salomoni, Yanxi Zhang
High Energy Physics (Phenomenology)
Formation of Supermassive Black Hole Seeds from Vacuum-Dependent Thermal Dark Matter
Masahiro Kawasaki, Jie Sheng and Tsutomu T. Yanagida
The origin of supermassive black holes, especially those already present at high
redshift, remains an open problem. We propose that their seeds are
primordial black holes formed from rare overdense regions of conventional thermal DM. A spectator scalar with two degenerate
vacua gives the DM different masses, and hence different freeze-out abundances, in the two
vacua. Inflationary fluctuations populate the
vacuum containing the heavier relic only in exponentially rare patches. As the Universe cools, the density contrast of these patches grows sufficiently large for the patches to collapse into PBHs after horizon re-entry. We derive the resulting PBH mass function and show that it is sharply concentrated near a lower cutoff while reproducing the mass scale and abundance required for SMBH seeds. Since the overdensities originate from a rare, non-Gaussian population rather than from an enhancement of nearly Gaussian
primordial curvature perturbations, the usual CMB spectral-distortion constraint does not directly apply. The construction also correlates the seed population with the dark-sector spectrum and the inflation scale, providing complementary avenues for testing the scenario.
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Optics
Beyond Group Delay: Fundamental Limits of Achromatic Metasurfaces
Roman Buisine, Nicolas Kossowski, Adelin Patoux et al. (+3 more)
Achromaticity is one of the most demanding functionalities achievable with a metasurface because it requires reproducing the same optical response over a finite spectral bandwidth rather than at a single wavelength. Although previous studies established aperture-bandwidth limits based on temporal-delay considerations, the role of optical performance on these limits has remained unresolved. Here, we develop a rigorous theoretical framework that explicitly highlights how the optical performance sets the true aperture-bandwidth limit of single interface achromatic metasurfaces, quantifying the fundamental limits through the Strehl ratio. We identified two distinct operating regimes. In the first, the achromaticity conditions are exactly satisfied, guaranteeing diffraction-limited performance across the entire bandwidth. Surprisingly, the maximum achievable aperture in this regime is essentially independent of bandwidth and is instead governed by the ability of practical meta-atoms to simultaneously realize the required phase and dispersion. In the second regime, relaxing the required optical performance allows larger apertures at the cost of a fundamental trade-off between aperture, bandwidth, and optical performance. Numerical validation using a large library of high-transmission GaN meta-atoms confirms the theory and reveals the transition between these regimes. Our framework establishes the fundamental limits of achromatic metasurfaces, providing practical design rules for balancing aperture, bandwidth, and optical performance of achromatic metasurfaces.
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All authors Roman Buisine, Nicolas Kossowski, Adelin Patoux, Patrice Genevet, Rémi Colom, Samira Khadir
Cosmology and Nongalactic Astrophysics
Third-order scalar induced gravitational waves during a matter-dominated era: secular growth and implications for primordial black hole domination
Jing-Zhi Zhou
We investigate scalar induced gravitational waves (SIGWs) at third-order during a matter-dominated (MD) era. We classify the sources into four parts—built from three first-order scalars, and from a first-order scalar times the second-order tensor, vector, and scalar perturbations—and obtain all four kernel functions analytically in closed form. Unlike their radiation-dominated counterparts, the MD kernel functions grow secularly, translating into a rapid growth of the spectrum, $\Omega^{(3)}_{\mathrm{GW}}\propto x^{6}$ versus $\Omega^{(2)}_{\mathrm{GW}}\propto x^{2}$ at $x\equiv k\eta\gg1$. We derive the third-order power spectrum as a five-fold integral for a general
primordial spectrum, and evaluate it numerically for a monochromatic one, where all contributions from the second-order vector source vanish identically. As an application, we consider the early MD era driven by
primordial black holes (PBHs) before their evaporation. Requiring that the induced gravitational waves do not backreact on the cosmological perturbations, $\int\mathrm{d}\ln k\, \Omega^{\mathrm{tot}}_{\mathrm{GW}}<1$ then bounds the initial PBH abundance as $\Omega_{\mathrm{PBH},f}\lesssim4.6\times10^{-7}\, (m_{\mathrm{PBH}}/10^{7}\,\mathrm{g})^{-0.48}$, about three orders of magnitude stronger than the second-order-only bound. Our results indicate that higher-order SIGWs inevitably become nonperturbative during a sufficiently long MD era, with important implications for scenarios involving an early matter domination.
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High Energy Physics (Theory)
On connection between associators and 6j-symbols
Elena Lanina, Artem Novokhatnii, Alexey Sleptsov et al. (+1 more)
We propose a new formula relating the rationalized Drinfeld associators obtained from the Knizhnik–Zamolodchikov equation to the
quantum $6j$-symbols of the
algebra $\mathcal{U}_q(\mathfrak{g})$: $ U_{q} = U \cdot \Phi^{KZ}_{\mathbb{Q}} $. We prove this relation in the case of the $\mathfrak{sl}_N$ Lie
algebra for the tensor cube of the fundamental and the first symmetric representation. We also check it perturbatively for the $\mathfrak{sl}_N$
algebra for representations $[2]\otimes [1] \otimes [1]$, $[2]\otimes [2] \otimes [1]$, the non-trivial cases with multiplicities — $[2,1]^{\otimes 3}$, $[2,2]^{\otimes 3}$, and in the case of the $\mathfrak{so}_5$ Lie
algebra for the tensor cube of the fundamental representation.
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All authors Elena Lanina, Artem Novokhatnii, Alexey Sleptsov, Radomir Stepanov
Materials Science
Dynamic Kinetic Evaluation Favors Compositionally Diverse Multicomponent Alloy Nanoparticles for Hydrogen Evolution
Koki Otsuka, Anh Khoa Augustin Lu, Koji Shimizu et al. (+1 more)
High-
entropy alloy (HEA) nanoparticles offer chemically diverse catalytic sites, but identifying optimal compositions across their large design space remains challenging. We developed a framework combining machine-learning energy prediction, thermodynamic Monte Carlo sampling,
Bayesian optimization, and kinetic Monte Carlo (kMC) simulations to screen 85-atom nanoparticle models across a nine-element composition space for the hydrogen
evolution reaction. Static optimization based on adsorption energies selected Pt-rich, low-component compositions, whereas kMC-based optimization ranked the multielement composition Au$_{33}$Co$_{20}$Cu$_{6}$Pd$_{26}$ highest among the evaluated candidates. Cycle-resolved analysis further showed hydrogen adsorption at Co/Pd-rich environments, migration through intermediate-binding sites, and frequent Heyrovsky desorption at weaker-binding, Au-containing environments. This pathway-level evidence supports a multisite reaction picture and illustrates how incorporating kinetics can complement static adsorption-energy screening.
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All authors Koki Otsuka, Anh Khoa Augustin Lu, Koji Shimizu, Satoshi Watanabe
Quantum Physics
Memory Separations from a Collective-Spin Quantum Register
Jamal Slim
A
spin one-half driven only by total-
spin operators generates a renewal process in which one interevent time $n^\ast$ is forbidden while all others occur. No classical hidden Markov model reproduces it with fewer than $1+\sqrt{n^\ast}$ states, an unbounded separation whose only resource is one relative phase of $\pi$. With $K$ amplitudes the same interference yields $K(K{+}1)/2$ decay channels, and for positive weights and generic rates the classical cost is exactly $K(K{+}1)/2$ states. Both are realized by a depth-three
circuit whose parameter count does not grow with the register.
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Geophysics
Ground roll suppression based on the synchrosqueezed wavelet transform and local adaptive subtraction filtering
Zifei Li, Zhengyu Tan and Shaohuan Zu
Ground roll suppression remains a challenge in land seismic data processing, particularly when strong surface wave energy exhibits significant overlap with effective reflection events in the low frequency band. Conventional approaches, such as frequency-wavenumber (F-K) filtering, Radon transform-based methods, and other spatial filtering techniques, often fail to achieve satisfactory results under such conditions due to limited resolution and poor amplitude preservation. To address this problem, a time-frequency domain ground roll suppression method that integrates the synchrosqueezed wavelet transform (SSWT) with local adaptive subtraction filtering is proposed. First, seismic traces are transformed from the time-space domain into the time-frequency domain using SSWT, which provides a highly concentrated time-frequency representation. Based on the distinct distribution characteristics of ground roll noise and effective reflection signals in the time-frequency domain, a ground roll model is extracted. Subsequently, a local adaptive subtraction filter is applied to adjust the amplitude and phase of the extracted ground roll model, and the corrected model is subtracted from the original seismic data to obtain the final suppressed result. Applications to both synthetic and field seismic data demonstrate that the proposed method effectively attenuates ground roll energy while maximally preserving the amplitude and waveform characteristics of reflection signals. Compared with conventional time-frequency-based ground roll suppression approaches, the proposed method exhibits superior amplitude fidelity and improved noise attenuation performance.
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Solar and Stellar Astrophysics
Does Diffusive Shock Acceleration Reach Steady State? Insights from a Near-Sun Shock Observed by Parker Solar Probe
Immanuel Christopher Jebaraj, Mikhail Malkov, Nicolas Wijsen et al. (+7 more)
Collisionless shocks accelerate particles at a rate set by the
diffusion coefficient of those particles in waves they themselves generate. Theory fixes that coefficient only in steady state, and no measurement has tested whether an evolving shock ever reaches that state. We report Parker
Solar Probe observations of a fast, near-parallel interplanetary shock at 0.24 au, encountered four hours after eruption, with the upstream waves and the
protons they scatter recorded on the same
magnetic field line. From the wave spectra alone we derive the parallel mean free path of 0.05-30 MeV
protons, resolved in energy and in distance from the shock. The mirror force of the measured compressive fluctuations supplies the scattering through the pitch angles that gyroresonance cannot reach. The mean free path grows with distance nearly as the steady self-generated solution requires, yet the steady balance holds at one energy only, near 1.3 MeV. The intensity profiles are a factor of two shallower than the measured coefficient predicts, because the waves are still growing. Confinement fails between 2.3 and 6 MeV, beginning a factor of two below what the age of the shock allows. The growth of the waves its own particles drive, rather than its age or its size, limits the energy an evolving shock confines.
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All authors Immanuel Christopher Jebaraj, Mikhail Malkov, Nicolas Wijsen, Oleksiy Agapitov, Athanasios Kouloumvakos, Alexandr Afanasiev, Federico Fraschetti, Edin Husidic, Christina Cohen, Rami Vainio
Atomic Physics
Total-field atomic magnetometry using an elliptically-polarized frequency-modulated light beam for geomagnetic-field applications
D.V. Brazhnikov, A.O. Makarov, K.S. Kozlova et al. (+10 more)
We investigate an all-optical scheme for high-sensitivity measurements of the Earth's scale
magnetic field ($B$). The scheme is based on the Bell-Bloom technique with frequency-modulated light. A single elliptically polarized light beam is used both for pumping the alkali-metal atoms and probing Larmor precession of their
spins under the external
magnetic field. In contrast to many other high-sensitivity magnetometry schemes based on nonlinear polarization rotation of the light, the proposed approach enables the observation of
magnetic resonance via changes in the light-beam ellipticity parameter. The approach has been validated in experiments with a vertical-cavity surface-emitting
laser, irradiating a $0.125$ cm$^3$ cesium vapor
cell filled with a buffer gas. In the current experimental conditions, the achieved sensitivity is estimated at $220$ fT/$\surd$Hz under $B$$\,\approx\,$$50$ $\mu$T, while the shot-noise floor corresponds to $\approx\,$$20$ fT/$\surd$Hz. The bandwidth is estimated at $\approx\,$$1$ kHz. The proposed simple and robust single-beam scheme is well suited for miniaturization and is therefore particularly promising for the development of compact, highly sensitive, low-power-consumption atomic magnetometers for a wide range of applications in the geomagnetic field.
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All authors D.V. Brazhnikov, A.O. Makarov, K.S. Kozlova, M.A. Rusina, A.M. Mikhailov, V.A. Vasiliev, E.V. Tanakov, A.N. Goncharov, M.A. Bobrov, Ya.N. Kovach, A.A. Blokhin, N.A. Maleev, S.A. Blokhin
Materials Science
Finite-Momentum Antiferromagnetic Magnon Dynamics across the Morin Transition in Hematite
Jiaqi Gong, Yuanzhe Tian, Jun Cui et al. (+6 more)
Hematite ($\alpha$-Fe$_2$O$_3$) is a prototypical
antiferromagnetic platform for high-speed spintronics and magnonics, yet its finite-momentum
magnon dynamics and
spin-reorientation mechanism remain incompletely understood. Here we use low-wavenumber magneto-Raman spectroscopy to resolve both $k=0$ and finite-$k$ sub-terahertz
magnons in $\alpha$-Fe$_2$O$_3$ across the Morin transition. We find that the limiting group velocity $v_0$ remains nearly field independent, whereas the finite-$k$ group velocity $v_{\mathrm g}$ is strongly modified near the Morin and
spin-flop transitions. By combining parallel- and transverse-field measurements with
spin-wave modeling, we further extract the temperature-dependent Dzyaloshinskii–Moriya field $H_{\mathrm D}$ and uniaxial anisotropy fields $H_{\mathrm{K1}}$ and $H_{\mathrm{K2}}$. We find that $H_{\mathrm D}$ is weakly temperature dependent at approximately 2.0–2.3~T, while $H_{\mathrm{K1}}$ decreases rapidly and $H_{\mathrm{K2}}$ changes only weakly. This contrast drives the sign reversal of the effective anisotropy field and quantitatively accounts for the Morin transition. Our results establish low-wavenumber Raman spectroscopy as a quantitative probe of finite-momentum
antiferromagnetic magnons and provide key material parameters for hematite-based magnonics.
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All authors Jiaqi Gong, Yuanzhe Tian, Jun Cui, Meiye Hou, Yuxuan Mu, Di Wang, Xiangang Wan, Di Wu, Qi Zhang
Statistical Mechanics
Spatial density, first passage times, and entropy of run and tumble particles in a bistable potential
R. K. Singh and Erez Aghion
We study the dynamics of a run and tumble particle (RTP) in a bistable potential, in contact with a heat bath. We find the exact form of the steady state position distribution as well as its time-dependent form in Laplace space. We use this result to study relaxation properties of the spatial probability density and find that it converges to the steady state from the center outwards, with the relaxation front moving ballistically in time. Physically this ballistic behavior arises when observing relaxation properties at the tails of the density, where the distance of the particle from the origin is larger than the length-scale describing the steady state of the RTP. We also find the exact form of the mean first passage time, and the long-time behavior of the first passage time distribution. This allows us to coarse-grain the dynamics as a dichotomous Markov process, a paradigm for a wide class of bistable processes. Coarse-graining, however, comes at the cost of a loss of information: while the RTP possesses a finite
entropy production even at steady state, it identically vanishes for its coarse-grained description.
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Quantum Physics
Broadband Telecom Entanglement from an All-Fiber Type-0 Sagnac Source
Alessandro Cestelli, Spyridon Grountas, Scott Mc Haffie et al. (+3 more)
We demonstrate a compact, practical all-fiber source of non-degenerate telecom-band polarization-entangled
photon pairs assembled from off-the-shelf components. The compact fiber-integrated architecture is designed to be affordable, straightforward to assemble and align, and compatible with existing optical-fiber infrastructure.
Photon pairs are generated through type-0 spontaneous parametric down-conversion in a pigtailed periodically poled lithium-niobate waveguide embedded in a Sagnac interferometer. At 0.5 mW pump power,
quantum-state
tomography yields a Bell-state fidelity $F_{\Phi^-}=0.850$, purity $P=0.836$, and concurrence $C=0.782$. A separate CHSH measurement gives $S=2.3301\pm0.0075$. The measured Bell-state fidelity is sufficient for the reconstructed polarization state to support
qubit teleportation above the classical fidelity limit under ideal protocol operations. Analysis of the density
matrix shows that approximately 96.7% of the population remains in the desired $|HH\rangle$-$|VV\rangle$ subspace, with a normalized coherence of approximately 0.86. A residual relative-phase offset indicates that local phase compensation could increase the Bell-state fidelity to approximately 0.8865. We further characterize the brightness–quality trade-off and obtain a corrected pair-rate slope of $(0.918\pm0.040)$ Mcps mW$^{-1}$. The broadband emission and fiber interfaces offer a route to multiuser
entanglement distribution through off-the-shelf multichannel wavelength-division multiplexers with passbands matched to the signal and idler wavelengths.
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All authors Alessandro Cestelli, Spyridon Grountas, Scott Mc Haffie, Jun Gao, Val Zwiller, Ali Elshaari
Fluid Dynamics
A Lagrangian analysis of coherent structures in 2D annular Rayleigh-Bénard convection
Luis Álamo, Jezabel Curbelo and Kathrin Padberg-Gehle
Convective instabilities are studied from a Lagrangian perspective in order to gain new insights into how the resulting global, long-lived coherent flow structures organize themselves. We consider a 2D annular fluid layer uniformly heated from the inside and subject to radial
gravity and propose several new Lagrangian diagnostics for characterizing its convective instabilities. In particular, we perform a comprehensive Lagrangian analysis of the flow field across a wide range of dimensionless parameters, establishing a heuristic correspondence between convective plumes and curves of local maxima of Finite-Time Lyapunov Exponent (FTLE) fields. Moreover, we characterize coherent swirling motions inside convective rolls, which are associated to the non-zero
curvature of the flow. By introducing a sliding window method for our finite-time kinematic measures, we demonstrate a direct relationship with radial heat flux quantified by means of the Nusselt number and identify relevant dynamical transitions that leave a trace on both. Finally, we propose a formal criterion for determining viscous boundary layer (UBL) thickness by virtue of radial FTLE profiles and validated against a classical Eulerian method.
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Cosmology and Nongalactic Astrophysics
Fast and accurate differentiable code of the galaxy power spectrum based on Eulerian and Lagrangian one-loop perturbation theories
Yosuke Kobayashi and Kazuyuki Akitsu
This paper presents a JAX-Python implementation of the
galaxy power spectrum up to one-loop order in the effective field theory of large-scale structure, based on both the Eulerian and Lagrangian perturbation theories. The code uses JAX to enable automatic differentiation with respect to parameters such as cosmology,
galaxy bias, or counterterm coefficients. This facilitates applications such as parameter inference using the gradient of the posterior, e.g.,
Hamiltonian Monte Carlo sampling. The code can compute both the EPT and LPT power spectra in a few milliseconds on a GPU, after just-in-time compilation. We also identify the various sources of numerical errors associated with discretization, and design the numerical implementation to minimize them, achieving relative errors of order $0.01\%$ at scales $k \lesssim 1\, h\, \mathrm{Mpc}^{-1}$, compared with brute-force numerical integration. Notably, this is the first auto-differentiable implementation of the one-loop
galaxy power spectrum based on LPT. The natural resummation of the long-wavelength displacements in LPT further makes the code well suited for applications involving features in the power spectrum beyond the standard BAO feature, including
primordial features. Our code, elf, is publicly available.
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Statistical Mechanics
Heterogeneous diffusion with recruitment and mortality
Esther D. Gutiérrez, Alexander López, R.K. Singh et al. (+3 more)
We study a heterogeneous
diffusion process with a position-dependent
diffusion coefficient in the presence of independent recruitment and mortality. This framework generalises heterogeneous
diffusion under
stochastic resetting, which is recovered as the special case of equal recruitment and mortality rates. At long times, the system approaches a non-
equilibrium stationary state with a mean squared displacement that saturates to a value independent of the recruitment rate. Crucially, this saturation limit directly encodes the underlying transport regime via an effective exponent applied to the
diffusion coefficient, and we characterise the non-trivial transition to this stationary regime. We further derive the mean first-passage time to a target and show that, for a fixed recruitment-to-mortality ratio, an optimal mortality rate minimises the search time. This "mortality-assisted search" effect is confirmed by numerical evaluation. Reinterpreting recruitment and mortality as infection and removal processes, we apply the model to epidemic spreading and show that a moderate removal rate can counter-intuitively accelerate, rather than delay, the arrival of infection at a new spatial region. Beyond epidemiology, our framework offers broad relevance to systems featuring concurrent particle creation and destruction, such as bacterial growth, tracer
diffusion in reactive fluids, or cellular population dynamics in crowded environments.
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All authors Esther D. Gutiérrez, Alexander López, R.K. Singh, Sébastien Fumeron, Malte Henkel, Trifce Sandev
Chemical Physics
Learning consistent molecular mechanics force fields from first principles
Berkay Günes, Leif Seute, Jigyasa Nigam et al. (+1 more)
Classical force fields (FFs) remain the workhorse for large-scale simulations even as machine-learned interatomic potentials (MLIPs) approach ab initio accuracy. They decompose total configuration energies into simple effective interactions whose parameters are traditionally assigned based on atom or bond types, enabling efficient simulations but also limiting their ability to adapt across configurations. Recent machine learning approaches have improved the accuracy and transferability of bonded parameters in these FFs by inferring them as functions of local atomic environments, but still rely on empirical nonbonded parameters for practical simulations. In this work, we introduce a unified approach, grappa-fullFF, which learns both bonded and nonbonded parameters consistently and simultaneously from ab initio reference data. By incorporating physically inspired regularization via supervision of the electrostatic potential and an architecture that facilitates charge equilibration, our model recovers accurate electric response properties, achieves state-of-the-art accuracy on geometry optimization
benchmarks, and reproduces the conformational sampling of both classical and existing machine-learned FFs, without relying on externally assigned nonbonded parameters.
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All authors Berkay Günes, Leif Seute, Jigyasa Nigam, Frauke Gräter
Materials Science
Defect-limited thermal transport in AlN using pretrained machine-learning interatomic potentials
Minseok Moon, Wonjun Choi, Seungwu Han et al. (+1 more)
Aluminum nitride (AlN) is an important thermal management material whose high
lattice thermal conductivity is strongly suppressed by oxygen
impurities. We investigate
phonon scattering by oxygen-related defects using pretrained universal machine-learning interatomic potentials (MLIPs), molecular dynamics (MD), and
phonon Boltzmann transport calculations. Several pretrained MLIPs are benchmarked against density functional theory for
phonon dispersions and pristine thermal conductivity. To balance accuracy and computational speed, we use a fine-tuned version of the compact SevenNet-Nano model for MD simulations. Monte Carlo annealing supports the formation of bound $V_{\mathrm{Al}}(\mathrm{O_N})_3$ complexes, whose scattering differs from that of their isolated constituents. Defect scattering rates extracted from excess spectral energy density (SED) linewidths agree reasonably with harmonic $T$-
matrix predictions at low oxygen contents, supporting the independent-scatterer approximation. Incorporating these rates into an iterative Boltzmann transport equation with Bose–Einstein statistics yields thermal conductivities comparable to experimental values and captures their observed decrease with oxygen content. At high concentrations, however, the scattering rate deviates from linear scaling with oxygen content, suggesting limitations of independent-defect and pristine-
phonon descriptions. These results demonstrate an efficient approach using pretrained MLIPs to quantify defect-limited thermal transport and provide insights into
impurity effects beyond the dilute-defect approximation.
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All authors Minseok Moon, Wonjun Choi, Seungwu Han, Youngho Kang
Quantum Physics
Cyclic triorthogonal codes in prime dimension
Shiroman Prakash
We study cyclic triorthogonal codes in
prime dimension $p$, on which a transversal third-level diagonal gate acts as a logical non-Clifford gate. For odd $p$, we use a definition of triorthogonality that does not require self-orthogonality. For cyclic codes of length coprime to $p$, triorthogonality reduces to a sumset condition on the spectral support, which makes exhaustive search feasible: for two natural constructions, we enumerate all maximal codes of this kind for $p=3$ up to length $121$ and $p=5,7$ up to length $96$. For
qubits, we prove that a cyclic code of odd length is triply even if and only if it is classically triorthogonal, giving a complete description of triply-even cyclic codes, and we determine all such codes up to length $763$. For qudits, we find codes such as $[[19,1,3]]_3$ and $[[7,1,3]]_7$, which improve on the shortest Reed-Muller and Reed-Solomon codes in both overhead exponent and
distillation threshold. The latter is the first member of an infinite family of $[[p,1,2\lfloor p/6\rfloor+1]]_p$ codes.
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General Relativity and Quantum Cosmology
Continuum Landscape of stable extra-dimensional metrics
Sergey G. Rubin
We investigate modified
gravity with quadratic
curvature terms ($R^2$, $R_{AB}R^{AB}$, and $R_{ABCD}R^{ABCD}$). In this framework, the geometry of the extra dimensions is determined by the higher-dimensional field equations together with auxiliary conditions. For inhomogeneous metrics, we derive new stability conditions under radion excitations. The central result is that stable solutions satisfying these conditions are not isolated: a typical stable regular metric belongs to a continuous family of stable metrics in its immediate neighbourhood. Since the effective four-dimensional physical parameters depend on the extra-dimensional geometry, this geometrical landscape of stable metrics induces a continuous landscape of effective four-dimensional parameters. Transitions between distinct static solutions within the landscape cannot be induced by spatially localized perturbations, whose asymptotic decay ($|x|\to\infty$) preserves the boundary data distinguishing the states. We also note a possible topological transition from a two-brane to a one-brane configuration, associated with a change in the number of regular zeros of the metric function $r(u)$.
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Quantum Physics
Squeezed light from a semiconductor amplifier
Andrey S. Aleksandrov and Anatoly V. Masalov
The possibility of generating light in a squeezed
quantum state during saturated light amplification in a
semiconductor amplifier is theoretically analyzed. Due to four-wave mixing process during amplification, weak components of the spontaneous emission of the medium with symmetric frequency shifts relative to the strong amplified wave acquire the
quantum properties of two-mode squeezed light. The squeezing of quadrature components occurs in the range of frequency shifts of several GHz ($\sim$ the inverse relaxation time of the charge carrier density) and can reach 10 dB or more under optimal conditions. The formation of a two-mode squeezing phase facilitates the observation of the squeezing effect, in which a strong wave, playing the role of a local wave, exhibits quadrature noise suppression without additional homodyne detection.
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High Energy Physics (Phenomenology)
Safety of dynamical SUSY breaking and gaugino condensation in models of spontaneous CP violation
Norimi Yokozaki
Solving the strong CP problem with spontaneous CP violation (SCPV) in SUSY requires that the constant term of the superpotential and the SUSY-breaking F-term be real to high accuracy. When both are generated dynamically, by gaugino condensation and by dynamical SUSY breaking (DSB), their phases need not vanish even if every theta-angle vanishes and every coupling is real; e.g., the multivalued non-perturbative superpotential may sit on a branch with a complex phase. In fact, gaugino condensation, in pure SUSY Yang-Mills theory and in its Affleck-Dine-Seiberg generalization, is safe only for N_c - N_f in {1,2} (N_c = 2 for pure SYM); otherwise the phase of the constant term reaches the gluino mass through anomaly mediation. The SUSY-breaking F-term is the main source of the MSSM soft masses, including the gluino mass, so its phase reaches theta-bar as well. In the framework of global SUSY, the 3-2 model introduces no phase. The ISS model is safe in that sector as long as the
quark-mass splittings exceed the messenger-loop corrections; when they fall below, a complex
vacuum orientation can generate an O(1) phase. The IYIT model can generate a purely imaginary F-term: for half of the real Yukawa parameter space, the
meson VEV is purely imaginary and CP is spontaneously broken. In all three, the
vacuum of the field coupled to the messengers is aligned with the constant term, so a complex constant term generates a strong CP phase through a second route, separate from anomaly mediation.
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Biological Physics
Spatiotemporal Oscillations Driven by Spatial Heterogeneity and Growth
Lewis S. Mosby, Mohit P. Dalwadi and Zena Hadjivasiliou
Temporal oscillations arise naturally in biological systems with feedback loops or explicit delays. When incorporating spatial effects, the travel times of propagating signals can also generate intrinsic delays, and this behaviour is complicated further in the presence of spatial heterogeneity. In this work, we investigate the mechanistic origin and dynamics of spatiotemporal oscillations driven by intrinsic diffusive delays in a representative activator-inhibitor system with spatial heterogeneity using a combination of mathematical modelling, simulations and numerical methods. In contrast to delay-differential equation models where delays are explicitly prescribed, in the partial differential equation system we consider here delays are an intrinsic consequence of signal travel time through space. We demonstrate that undamped oscillations can arise as a result of spatially heterogeneous feedback when the system size increases through a critical length. At this critical length the time for systems to reach steady-state diverges, and the systems first exhibit an
eigenvalue with a positive real part and non-zero imaginary part, corresponding to a
Hopf bifurcation. We infer that this critical length could define a theoretical upper limit for the size of systems where oscillations hinder function. The analysis pipeline derived in this work offers a novel route for understanding the onset of spatiotemporal oscillations and
Hopf bifurcations in a diverse array of biological systems where interactions are mediated by diffusive species.
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Mathematical Physics · Cross-listed from math.QA
A new $SL_2$-action on the rank-two $\beta\gamma$-system
Tomoyuki Arakawa, Xuanzhong Dai and Bailin Song
We construct an explicit rational \(\mathrm{SL}_2(\mathbb C)\)-action on the underlying vector space of the rank-two \(\beta\gamma\)-system. The construction is motivated by Creutzig's branching decomposition with respect to \(L_{-1}(\mathfrak{sl}_2)\) and a rank-one Heisenberg vertex
algebra. We realize the raising and lowering operators as residues of
lattice-type fields, prove that they preserve the original \(\beta\gamma\)-system despite being defined on localizations, and establish their commutation relations and integrability. The resulting action commutes with the affine \(L_{-1}(\mathfrak{sl}_2)\)-action and all nonzero Heisenberg modes, while the Heisenberg zero mode serves as its Cartan operator. Each affine multiplicity space is thereby identified with \(V_n\otimes\mathcal F_{\mathrm{osc}}\), where \(V_n\) is the irreducible \(\mathrm{SL}_2(\mathbb C)\)-module of highest weight \(n\) and \(\mathcal F_{\mathrm{osc}}\) is the Heisenberg oscillator Fock space. Thus the Heisenberg charge decomposition is realized as the weight decomposition of \(V_n\). The infinitesimal action is not by vertex
algebra derivations and does not preserve the symmetric conformal grading.
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Quantum Physics
A Single Conformal Coordinate Decodes Outcome-Resolved Measurement-Induced Entanglement
Reyhaneh Khasseh and M.A. Rajabpour
A local measurement of a critical many-body state produces exponentially many microscopic outcomes, each defining a different conditioned
quantum state. We ask how much information from one such outcome is actually needed to predict the
entanglement that remains between two unmeasured regions. We show that, in critical
quantum chains, the universal outcome-resolved Rényi
entropy is asymptotically determined by a single compact conformal coordinate extracted directly from the measurement record. Compact-
boson theory explains this compression: the universal
entropy is insensitive to all spatially varying components of the boundary profile, retaining only a single relative compact zero mode. At the free-
fermion XX point, exact
lattice identities expose the microscopic structure underlying the decoder, while large-scale outcome-by-outcome calculations confirm its scaling prediction across different subsystem geometries and Rényi indices. Numerical calculations in interacting XXZ chains further show that the same microscopic coordinate continues to decode the conditional
entropy without interaction-dependent retuning. Thus an exponentially large space of measurement outcomes is reduced, for this universal observable, to a single conformal degree of freedom, revealing an emergent Luttinger-
liquid mechanism for outcome-resolved postmeasurement
entanglement.
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Quantum Physics
Entanglement Swapping Scheduling for Quantum Repeater Chains under Decoherence during Classical Communications
Jorge Benito Díaz, Andrés Agustí, Jabier Faba et al. (+3 more)
First-generation
quantum repeaters are essential in distributing
entanglement over long distances since they could mitigate losses in optical fiber. Repeaters split the total distance into shorter, easier to generate links. Then,
entanglement swapping establishes long range
entanglement by performing local measurements at the repeaters and heralding their results. In this work, we develop an analytical model that estimates the impact of decoherence during heralding for a given protocol. Furthermore, we identify a competition between two phenomena: as repeater count increases, so does
entanglement generation, but the additive impact of
memory decoherence on final
entanglement rate increases too. Therefore, we find that an optimal number of repeaters exists. These findings could lead the design of future
quantum networks, both in the inter-repeater distance and swapping timings.
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All authors Jorge Benito Díaz, Andrés Agustí, Jabier Faba, Laura Ortiz, Luis Robledo, Vicente Martín