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Physics

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Wednesday 2 September

High Energy Physics (Phenomenology)

Inelastic Dark Photon Dark Matter for the LUX-ZEPLIN High-Recoil Event and the Galactic Halo Gamma-Ray Excess

Kimiko Yamashita

We show that a dark-photon dark matter framework can simultaneously account for two recently reported anomalies: the halo-like Galactic gamma-ray excess identified by Totani in 15 years of Fermi-LAT data, and the $E_{\rm nr}=248\pm23\,({\rm stat})\pm23\,({\rm sys})$ keV nuclear-recoil event of interest reported by the LUX-ZEPLIN Collaboration. The dark matter is a $U(1)_X$ dark photon $X$ with mass $m_X=420$ GeV, stabilized by a dark parity that forbids kinetic mixing with the Standard Model photon. A light scalar mediator $\phi$, required to explain the Totani excess via Sommerfeld enhancement, is joined by a second light scalar $\phi'$ that couples a nearly degenerate heavier vector partner $V$ to $X$. The resulting inelastic transition $X+N\to V+N$, with mass splitting $\delta\simeq316$ keV close to the kinematic endpoint for $m_X=420$ GeV, naturally reproduces the localized LZ event once the detector energy resolution is included, while leaving the relic abundance and the halo phenomenology of the original Totani-motivated benchmark essentially unchanged.
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High Energy Astrophysical Phenomena

Magnetized accretion onto rapidly spinning binary black holes: mini-disk thermodynamics, magnetic transport, and dual jets

Luciano Combi, Manuela Campanelli, Sean M. Ressler et al. (+2 more)

Supermassive binary black holes embedded in gas-rich environments are promising multi-messenger sources for pulsar timing arrays and future space-borne gravitational-wave interferometers. Their electromagnetic emission is governed by nonlinear plasma dynamics around the binary and is expected to inherit variability associated with the orbital motion thereof. Because active galactic nuclei are intrinsically stochastic, identifying robust binary signatures requires predictive models that connect large-scale circumbinary flows to the black holes. Previous relativistic simulations of accreting binaries have mostly focused on smaller separations and lower spins. We perform three-dimensional general relativistic magnetohydrodynamic simulations of a relaxed, magnetized circumbinary disk accreting onto an equal-mass binary black hole with a separation of $30$ gravitational radii and dimensionless spin $\chi=0.9$. At these separations, the mini-disks around each black hole are persistent mass reservoirs but still show pronounced amplitude modulations governed by the eccentric circumbinary disk and the sloshing gas between the mini-disks. We analyze how the magnetic flux is transported from the circumbinary disk to the horizons, launching powerful dual jets with energy extraction efficiencies reaching $\approx 40\%$. The horizon-threading flux and jet luminosity alternate between the two black holes, producing an on-off dual-jet state. The wide jet funnels interact above the binary and form a persistent current sheet favorable to reconnection. We explore the influence of mini-disk thermodynamics, comparing efficient and inefficient cooling inside the cavity. Hotter mini-disks are less massive, exhibit weaker coherent periodicity, and launch less luminous jets despite comparable horizon-threading magnetic flux.
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All authors Luciano Combi, Manuela Campanelli, Sean M. Ressler, Alexander J. Dittmann, Federico Cattorini

Quantum Physics

A quantum oracle separation between QMA(2) and QMA

John Bostanci, Sabee Grewal, Jonas Haferkamp et al. (+4 more)

We find a quantum oracle relative to which $\mathsf{QMA} \neq \mathsf{QMA}(2)$. As a consequence, we resolve the no-disentanglers conjecture of Watrous: for every $\epsilon+\delta<1$, any $(\epsilon,\delta)$-disentangler requires input size exponential in the number of output qubits. Our proof combines the unitarily invariant polynomial method of She and Yuen (ITCS '23) with a new construction based on the symmetric and antisymmetric subspace projectors, reducing the $\mathsf{QMA}$ lower bound to the approximate degree of $\mathrm{OR}$.
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All authors John Bostanci, Sabee Grewal, Jonas Haferkamp, Andrew Huang, Yeongwoo Hwang, Anand Natarajan, Chinmay Nirkhe

High Energy Astrophysical Phenomena

Vortex pinning and the elastic response of neutron-star crusts II. Non-axisymmetric loading and Magnus mountains

Elia Giliberti

Pinned superfluid vortices transmit a Magnus force to the neutron-star crust. A non-axisymmetric component of the superfluid-lattice lag can therefore support a persistent mass quadrupole. We calculate the l=m=2 response of self-gravitating, radially stratified spherical stars with SLy4 and BSk21 backgrounds, using a local microscopic pinning cap and a density-dependent Coulomb-lattice shear modulus. For a 1.4 M_sun star at 100 Hz, the equilibrium-compression maxima are epsilon=2.67x10^-9 (SLy4) and 2.44x10^-9 (BSk21). The global quadrupole is strikingly insensitive to the shear prescription: replacing mu=0.01P by the Coulomb profile and strongly varying uncertain edge layers changes the result only at the percent level. The dominant internal sensitivity is instead compressional. A density-resolved compressional kernel increases through the inner crust and steepens close to the crust-core interface, particularly for BSk21, showing that the deep inner crust controls the EoS dependence of the mountain. A fixed-composition calculation is used only as a non-relaxed sensitivity diagnostic, not as the secular prediction. At a common true local velocity benchmark, our fiducial ellipticities remain more than an order of magnitude below the complementary two-component cylindrical calculation of Gangwar & Jones (2026). We argue that the comparison points to the relative superfluid-lattice degree of freedom as the natural next ingredient for a common spherical model. The main result is therefore physical rather than numerical: the Magnus-mountain scale is robust to shear microphysics, while the deep-crust compressional response sets the leading uncertainty of the one-displacement model.
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Instrumentation and Methods for Astrophysics

High performance Stingray

Eleonora Veronica Lai, Matteo Bachetti, Maura Pilia et al. (+4 more)

X-ray astrophysical objects show variability on a wide range of timescales, i.e. from fractions of second to years. The open-source Python library stingray is able to perform time series analyses with a focus on high-energy astrophysics. Comprising the most commonly used Fourier analyses techniques, it also supports a range of additional extensions able to analyse pulsar data, simulate data sets and perform statistical modelling. With the latest release of the code, new Fourier methods and support for additional missions have been implemented, making Stingray more easily adaptable and extendable to other use cases. In this paper we focus on testing the performance and robustness of the latest version of stingray . We consider the possible different behaviour of the code when dealing with data sets smaller or larger than the RAM. We address the problem of dealing with large data sets and implemented parallel versions of the slowest methods in this regime. For small data sets, we investigate the possibility of a porting in GPU of key functions of the code.
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All authors Eleonora Veronica Lai, Matteo Bachetti, Maura Pilia, Daniela Huppenkothen, Matteo Lucchini, Guglielmo Mastroserio, Hamza El Byad

Earth and Planetary Astrophysics

The Ultraviolet Spectrograph on ESA's Jupiter Icy Moons Explorer Mission (JUICE-UVS)

Kurt D. Retherford, Philippa M. Molyneux, Thomas K. Greathouse et al. (+51 more)

The Jupiter Icy Moons Explorer (JUICE) mission, led by ESA, has an Ultraviolet Spectrograph (JUICE-UVS) contributed by NASA and built at Southwest Research Institute. JUICE-UVS is designed to provide a diversity of measurements to further our understanding of the potential habitability of icy ocean worlds at Jupiter and to study Jupiter and the Jovian system as an archetype for gas giants. JUICE-UVS observes photons in the 50-204 nm wavelength range at moderate spectral and spatial resolution along a 7.5 deg slit composed of 7.3 deg x 0.1 deg and 0.2 deg x 0.2 deg contiguous sections. JUICE-UVS performs a comprehensive study of icy satellite atmospheres, plumes, surfaces, and local space environments; Jupiter's atmosphere and aurora; Io and its Io Plasma Torus; and other Jupiter system targets (rings, small moons, etc.) as available. The variety of observational techniques employed include: nadir push-broom imaging, disk scans, limb stares, stellar and solar occultations, Jupiter transit observations, and neutral cloud/plasma torus stares and scans. This paper describes the UVS investigation's science plans, instrument details, concept of operations, and data formats in the context of the JUICE mission's habitability and Jupiter system goals.
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All authors Kurt D. Retherford, Philippa M. Molyneux, Thomas K. Greathouse, Michael W. Davis, G. Randall Gladstone, Steven C. Persyn, Maarten H. Versteeg, Mary F. Araujo, Fran Bagenal, Tracy M. Becker, Arnaud Beth, Ronald K. Black, Bertrand Bonfond, Shawn M. Brooks, Emma J. Bunce, Alain Carapelle, Steven Cortinas, Gregory J. Dirks, Bryan Esquivel, Paul D. Feldman, Sue Ferrell, Mark Ferris, Leigh N. Fletcher, Matthew A. Freeman, Marina Galand, Rohini S. Giles, Denis Grodent, Vincent Hue, Erica Johnson, Joshua A. Kammer, Cynthia Kempe, Laurent Lamy, Adrian Martin, Melissa A. McGrath, Edward G. Nerney, Carlos Nuñez, Zachary Olsen, Norman Pelletier, Brandon Perez, Kristian B. Persson, Eric Quémerais, Rick Raffanti, Ujjwal Raut, Ryan Rickerson, Lorenz Roth, Oswald H. W. Siegmund, John R. Spencer, Andrew J. Steffl, Bradley J. Trantham, John V. Vallerga, Todd J. Veach, Michael A. Velez, Brandon C. Walther, the JUICE-UVS Team

High Energy Astrophysical Phenomena

LHAASO-WCDA observed a $\sim$ 5 days TeV-delayed flaring event in blazar 1ES 1959+650

Zhen Cao, F. Aharonian, Y.X. Bai et al. (+342 more)

We report a day-scale hard lag between GeV and TeV $\gamma$-ray emission from the HBL 1ES~1959+650 in early 2024. Since the LHAASO-WCDA real-time monitoring system began operation in late 2023, multiple TeV flares from this source have been triggered, including the 1st trigger flare on 2024 February 9. A Bayesian-block analysis of the WCDA light curve identifies three TeV flares in 2024. For the second triggered flare, a discrete cross-correlation analysis reveals a $>3\,\sigma$ correlation (relative to uncorrelated red-noise simulations) at a time delay of $\Delta t = 5.0_{-2.1}^{+2.1}$ days, with the TeV emission lagging the GeV. Time-resolved spectroscopy shows that this flare has the softest TeV spectrum among these flares (intrinsic spectral index $\Gamma=3.16\pm0.18$), while the 1st trigger flare is harder ($\Gamma=2.48\pm0.21$). The observed five-day hard lag is difficult to reconcile with a purely cooling-driven temporal ordering and is consistent with scenarios in which particle energization and/or transport may contribute to the evolution. However, the current data do not uniquely identify the underlying mechanism.
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All authors Zhen Cao, F. Aharonian, Y.X. Bai, Y.W. Bao, D. Bastieri, X.J. Bi, Y.J. Bi, W. Bian, J. Blunier, A.V. Bukevich, C.M. Cai, W.Y. Cao, Zhe Cao, J. Chang, J.F. Chang, E.S. Chen, G.H. Chen, H.K. Chen, L.F. Chen, Liang Chen, Long Chen, M.J. Chen, M.L. Chen, Q.H. Chen, S. Chen, S.H. Chen, S.Z. Chen, T.L. Chen, X.B. Chen, X.J. Chen, X.P. Chen, Yang Chen, Yong Chen, N. Cheng, Q.Y. Cheng, Y.D. Cheng, Y.H. Chi, M.Y. Cui, S.W. Cui, X.H. Cui, Y.D. Cui, B.Z. Dai, H.L. Dai, L.X. Dai, Z.G. Dai, Danzengluobu, Y.X. Diao, A.J. Dong, X.D. Duan, J.H. Fan, Y.Z. Fan, J. Fang, J.H. Fang, K. Fang, C.F. Feng, H. Feng, L. Feng, S.H. Feng, X.T. Feng, Y. Feng, Y.L. Feng, S. Gabici, B. Gao, Q. Gao, W. Gao, C. Ge, M.M. Ge, T.T. Ge, L.S. Geng, G. Giacinti, G.H. Gong, Q.B. Gou, M.H. Gu, W.M. Gu, F.L. Guo, J. Guo, K.J. Guo, X.L. Guo, Y.Q. Guo, R.P. Han, O.A. Hannuksela, M. Hasan, H.H. He, H.N. He, J.Y. He, X.Y. He, Y. He, S. Hernández-Cadena, C. Hou, X. Hou, H.B. Hu, S.C. Hu, D.H. Huang, F. Huang, J.J. Huang, X.L. Huang, X.T. Huang, X.Y. Huang, Y. Huang, Z.J. Huang, A. Inventar, X.L. Ji, H.Y. Jia, K. Jia, S.M. Jia, H.B. Jiang, K. Jiang, X.W. Jiang, Z.J. Jiang, C.C. Jin, M. Jin, S. Kaci, M.M. Kang, I. Karpikov, D. Khangulyan, D. Kuleshov, K. Kurinov, W.H. Lei, Cheng Li, C.K. Li, Cong Li, D. Li, F. Li, H.B. Li, H.C. Li, Jian Li, Jie Li, K. Li, L. Li, R.L. Li, T.Y. Li, W.L. Li, X.R. Li, X.Y. Li, Y. Li, Zhe Li, Zhuo Li, E.W. Liang, Y.F. Liang, S.J. Lin, B. Liu, C. Liu, D. Liu, D.B. Liu, H. Liu, J. Liu, J.L. Liu, J.R. Liu, M.Y. Liu, Q. Liu, R.Y. Liu, S.M. Liu, T. Liu, W. Liu, Y. Liu, Y. Liu, Yuan Liu, Y.N. Liu, Y.Q. Lou, Q. Luo, Y. Luo, H.K. Lv, B.Q. Ma, L.L. Ma, X.H. Ma, I.O. Maliy, J.R. Mao, Z. Min, W. Mitthumsiri, Y. Mizuno, G.B. Mou, A. Neronov, C.-Y. Ng, K.C.Y. Ng, M.Y. Ni, L. Nie, L.J. Ou, Z.W. Ou, H.W. Pan, P. Pattarakijwanich, Z.Y. Pei, D.Y. Peng, J.C. Qi, M.Y. Qi, J.J. Qin, H. Qu, A. Raza, C.Y. Ren, M.Q. Ruan, D. Ruffolo, A. Sáiz, D. Savchenko, D. Semikoz, L. Shao, O. Shchegolev, Y.Z. Shen, X.D. Sheng, F.W. Shu, H.C. Song, Yu.V. Stenkin, Y. Su, C.Y. Sun, D.X. Sun, H. Sun, J.X. Sun, M. Sun, Q.N. Sun, X.N. Sun, Z.B. Sun, N.H. Tabasam, J. Takata, P.H.T. Tam, H.B. Tan, Q.W. Tang, R. Tang, Z.B. Tang, L. Tao, W.W. Tian, C.N. Tong, L.H. Wan, C. Wang, D.H. Wang, G.W. Wang, H.G. Wang, J.C. Wang, J.F. Wang, J.S. Wang, K. Wang, Kai Wang, Kai Wang, L.P. Wang, L.Y. Wang, W. Wang, X.G. Wang, X.J. Wang, X.Y. Wang, Y. Wang, Y.D. Wang, Z.H. Wang, Z.X. Wang, Zheng Wang, D.M. Wei, J.J. Wei, Y.J. Wei, T. Wen, S.S. Weng, C.Y. Wu, H.R. Wu, Q.W. Wu, S. Wu, X.F. Wu, Y.S. Wu, S.Q. Xi, J. Xia, G.M. Xiang, D.X. Xiao, G. Xiao, Y.F. Xiao, B.H. Xie, F. Xie, Y.L. Xin, H.D. Xing, Y. Xing, D.R. Xiong, B.N. Xu, C.Y. Xu, D.L. Xu, R.X. Xu, S.S. Xu, L. Xue, D.H. Yan, T. Yan, C. Yang, C.Y. Yang, F.F. Yang, L.L. Yang, M.J. Yang, R.Z. Yang, W.X. Yang, Z.H. Yang, Z.G. Yao, X.A. Ye, L.Q. Yin, N. Yin, X.H. You, Z.Y. You, Y.H. Yu, Q. Yuan, W.M. Yuan, H. Yue, H.D. Zeng, T.X. Zeng, W. Zeng, X.T. Zeng, M. Zha, B. Zhang, B.B. Zhang, B.T. Zhang, C. Zhang, H. Zhang, H.M. Zhang, H.Y. Zhang, J. Zhang, J.L. Zhang, J.Y. Zhang, L.Y. Zhang, Li Zhang, P.F. Zhang, R. Zhang, R.Y. Zhang, S.R. Zhang, S.S. Zhang, S.Y. Zhang, W. Zhang, X. Zhang, X.L. Zhang, X.P. Zhang, Yi Zhang, Yong Zhang, Z.P. Zhang, H.S. Zhao, J. Zhao, L. Zhao, L.Z. Zhao, X.H. Zhao, F. Zheng, T.C. Zheng, B. Zhou, H. Zhou, J.N. Zhou, L. Zhou, M. Zhou, P. Zhou, R. Zhou, X.X. Zhou, X.X. Zhou, B.Y. Zhu, C.G. Zhu, F.R. Zhu, H. Zhu, K.J. Zhu, Y.F. Zhu, Z.F. Zhu, Y.C. Zou, X. Zuo

Exactly Solvable and Integrable Systems

Inverse scattering method for nonlinear negative first order coupled Klein-Gordon equation

Cihan Sabaz, Ilmar Gahramanov and Mansur I. Ismailov

The exact N-soliton solutions are derived for the coupled negative first order Klein-Gordon (CNKG) equation subject to vanishing boundary conditions by using the inverse scattering method via Gelfand-Levitan-Marchenko equation. Based on the zero-curvature representation, the conservation laws, integrals of motion, and Hamiltonian structure of the aforementioned coupled nonlinear equations are constructed. The Jost functions and their analyticity properties for the Manakov spectral problem are recalled. The integral equations for the eigenfunctions are then used to formulate the Gel'fand-Levitan-Marchenko equations. Solving these equations establishes a direct correspondence between the kernel functions and the potential, yielding the general N-soliton expressions.
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Quantum Physics

Exponential speedup of polarization stabilization for long distance DWDM quantum networks

Jinyi Du, En Teng Lim, Xingjian Zhang et al. (+4 more)

Fibre-based quantum networks distributing polarization entanglement require a stable and uninterrupted transmission basis for reliable operation. Bright classical reference light enables rapid polarization feedback but can introduce noise into quantum channels. Entangled-photon-based feedback avoids this noise, but typically interrupts the target entanglement channel during calibration and becomes prohibitively slow over long distances due to the product loss of fibre links. Here, we overcome both limitations by combining wavelength-bracketed probing with switch-enabled path decomposition. Spectrally adjacent entangled-photon sidebands track the polarization response of the central distribution channel without interrupting its transmission, while optical switches and local reference fibres independently determine the signal and idler network transformations. Transferring the resulting compensation settings to the central channel eliminates calibration-induced downtime and changes the acquisition-time scaling from the product of the link losses to the sum of losses. We demonstrate the method on a 133 km fibre testbed and achieve continuous closed-loop stabilization for more than 24 hours without classical reference light. The decomposition of multi-link quantum feedback into single-link measurements provides a scalable stabilization strategy for wavelength-multiplexed quantum networks.
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All authors Jinyi Du, En Teng Lim, Xingjian Zhang, Hongwei Gao, George F.R. Chen, Dawn T. H. Tan, Alexander Ling

Lattice Field Theory

On the equivalence of left-hand-cut and three-body formalisms

André Baião-Raposo, Raul Briceño and Sebastian M. Dawid

The "left-hand cut problem" in lattice QCD arises when exchange singularities invalidate standard relations used to extract scattering amplitudes from the finite-volume spectrum. In recent years, several approaches were proposed to resolve this problem. We establish analytically and verify numerically the equivalence between the three-body approach proposed in [JHEP 06 (2024) 051] and the two-body left-hand cut formalism developed in [JHEP 08 (2024) 075]. We test the equivalence in a scalar model describing a particle scattering from an $S$-wave two-particle bound state through one-particle exchange. Both approaches reproduce the same infinite-volume particle–bound-state amplitude and correctly encode the associated left-hand cut in the finite-volume spectrum. Crucially, we identify that the exponentially suppressed finite-volume effects neglected in both formalisms can be numerically large, compromising amplitude extraction at small lattice volumes.
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Computational Physics

Learning Spectrally Optimised Mesh-Free Discretisations

Lucas Gerken Starepravo, Henry Broadley, Steven Lind et al. (+1 more)

Numerical methods for partial differential equations (PDEs) discretise differential operators, ideally reproducing the action of the continuous operators across all wavenumbers permitted by a given discretisation. Spectral-type methods approach this ideal, but rely on structured grids or high-order meshes that are hard to generate for complex geometries. In contrast, mesh-free methods are geometrically flexible, yet how faithfully they reproduce the operator across resolved scales is strongly influenced by a heuristically chosen kernel, which selects one of many weight sets satisfying the same consistency conditions without regard to the resulting spectral response. To address this, we introduce Spectrally optimised Neural Discretisations (SpeND), a framework that learns the map from local stencil geometry to discretisation weights on unstructured point clouds. A projection layer constrains every predicted stencil to the affine set defined by the discrete moment conditions, so polynomial consistency, and hence formal order of accuracy, holds exactly. Since consistency is enforced by the architecture, the weights can additionally be optimised for accuracy on a prescribed function space. Herein, we use Fourier modes and target the exact differentiation response over a chosen wavenumber band, so training is unsupervised. The loss function is a design interface: changing how it weights wavenumbers yields operators with distinct accuracy profiles. The trained discrete differential operators are PDE-agnostic and are applied without retraining to the Poisson, Burgers and Navier–Stokes equations, to near-boundary stencils, and across resolutions. At the same order and resolution, SpeND matches or improves on established mesh-free discretisations, and has been shown to reduce the wall-clock time between $3-20\times$ to achieve equivalent error as the baselines.
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All authors Lucas Gerken Starepravo, Henry Broadley, Steven Lind, Jack R. C. King

High Energy Physics (Experiment)

Effective Sub-Quantum Readout for Non-Monochromatic Axion Signals in High-$Q$ Haloscopes

Junu Jeong and Max Silva-Feaver

The search for wave-like dark matter using microwave cavity haloscopes is constrained by the Standard Quantum Limit, which dictates that phase-preserving linear amplification results in a minimum of one quantum of total system noise for a narrow-band signal. We demonstrate that this limit is effectively halved for a non-monochromatic axion signal coupled to a high-$Q$ cavity. By operating a Josephson Parametric Amplifier such that the cavity resonance is centered exactly at the half-pump frequency, the axion signal symmetrically populates both the signal and idler bands. Through quadrature analysis of the homodyne readout, we show that the incoherent sum of these mirrored spectral components doubles the measured signal power while the vacuum noise remains constant. This operation yields an effective noise limit of 0.5 quanta per frequency bin, translating to an overall effective limit of $1/\sqrt{2}$ quanta after optimal matched filtering.
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Quantum Physics

Model-level synthetic-flux control of hyperchaos order and matched-resource sensing in dissipative optomechanics

Stella Rolande Mbokop Tchounda, Carolle Tchodimou, Philippe Djorwe et al. (+2 more)

Within a normalized six-dimensional model of dissipative optomechanics (one cavity + two mechanical resonators), a synthetic-flux phase $\Phi_{\rm syn}$ acts as a reproducible control coordinate that selects the order of a drive- and coupling-gated hyperchaos transition—up to four simultaneously positive Lyapunov exponents, beyond any reported single-mode benchmark. A phase-consistent Floquet–Lyapunov protocol (cross-checked by monodromy multipliers, dissipative volume balance $\sum\lambda_i=\operatorname{Tr}(J)=-1.04$ and a 180-run three-seed audit) localizes the onset to a Neimark–Sacker bifurcation at $E^{*}=\num{1.060}$ ($\theta=0$). As a secondary, model-level geometric clarification, the identical matched-resource force-sensing protocol returns a null gain on the chaotic attractor ($\mathcal{G}_{A/B}=\num{1.039}\pm\num{0.014}$), consistent with the matched-Fisher lemma: noise projected onto an unstable manifold is stretched by the same factor $e^{\lambda t}$ as the deterministic signal. Truncated-Fock and truncated-Wigner checks support the mean-field description at selected points. All results remain strictly model-level: the strong-coupling sector lies $\num{2542}\times$ beyond anchored silicon optomechanical couplings. Closing that gap requires ultrasonic characterization of the mechanical degeneracy $\omega_2$, a measured inter-resonator hopping $J_m$, and the emergence of a genuine gigahertz platform.
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All authors Stella Rolande Mbokop Tchounda, Carolle Tchodimou, Philippe Djorwe, Sifeu Takougang Kingni, Serge Guy Nana Engo

2609.02827 · 2 Sep · Main manuscript: 20 pages, 9 figures, 1 table. SI: 16 pages, 1 figure. Total: 36 pages, 10 figures, 1 table. Title updated to emphasize the primary result: synthetic-flux control of hyperchaos order, Neimark-Sacker bifurcation and full Lyapunov spectrum up to four positive exponents. The matched-resource sensing analysis is retained as a secondary geometric bound, matched-Fisher lemma

Abstract PDF $BNCH ×1$GEOM ×1$MNFD ×1

General Relativity and Quantum Cosmology

Charged black-hole binary radiation at second post-Newtonian order

Andrea Placidi, Elisa Grilli, Matteo Pegorin et al. (+1 more)

In this work, we build on Ref.~[Phys.~Rev.~D 112, 124060 (2025)], where we derived the dynamics of an electrically charged binary system at second post-Newtonian (2PN) order, by extending the analysis, at the same PN accuracy, to the associated emission of electromagnetic and gravitational radiation. We focus on non-spinning binaries that evolve quasi-adiabatically along a sequence of circular orbits, and compute the 2PN expression for the corresponding total energy flux at infinity. With respect to the well-known case of a neutral binary, the presence of charge induces both a new leading-order electromagnetic contribution of dipolar nature and additional charge-dependent corrections in the gravitational sector. To account for this richer phenomenology, we extend both the PN-matched multipolar post-Minkowskian and the effective field theory approaches to the radiation sector of charged binaries, with exact agreement for the contributions computed independently in both formalisms. We derive the radiative symmetric-trace-free multipole moments of the vector and gravitational fields at 2PN order. In doing so, we also compute 2PN-accurate charge-dependent corrections to the spherical multipoles of the waveform emitted by the binary, including a new memory contribution sourced by the stress-energy tensor of the electromagnetic radiation. These results lay the foundation for developing accurate waveform models capable of assessing the observational signatures of electric charge in gravitational-wave signals.
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All authors Andrea Placidi, Elisa Grilli, Matteo Pegorin, Marta Orselli

Chemical Physics

Low-Temperature Transport in Li-Ion Battery EC/EMC/FEC Electrolytes: Molecular Dynamics and Machine-Learning Modeling

İpek Yenda Ç{\i}nar, Oguzhan Orhan, M. Oluş Özbek et al. (+1 more)

Low-temperature operation imposes severe limitations on lithium-ion transport in battery electrolytes, yet the coupled effects of solvent composition and fluorinated additives in the cold-temperature regime remain insufficiently resolved. Here, we combine classical molecular dynamics (MD) and machine learning (ML) to investigate 1 M LiPF$_6$ electrolytes containing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and EC/EMC (3:7), with 0-10 mol% fluoroethylene carbonate (FEC), from 298 to 233 K. MD simulations quantify Li$^+$ self-diffusion, Nernst-Einstein (NE) and Green-Kubo (GK) conductivities and local coordination, while Gaussian-process surrogates model conductivity across composition and temperature. Cooling produces a pronounced transport penalty, particularly in EMC-containing electrolytes, whose GK conductivity decreases by more than 98% at 233 K, compared with approximately 90% in EC-rich systems. Li$^+$ self-diffusion activation energies are 0.49-0.54 eV for EMC-containing systems and 0.27-0.29 eV for EC-based systems. Within the EC family, 0-2 mol% FEC gives comparable cold-temperature transport, whereas 5-10 mol% FEC shows lower conductivity retention at the coldest simulated temperature. The analyzed coordination channels remain solvent dominated, while direct Li$^+$-FEC coordination is not quantified in the present RDF set.The Gaussian-process surrogates achieve composition-disjoint cross-validated RMSE values of 0.56 and 0.57 mS cm$^{-1}$ for NE and GK conductivity. Within the simulated liquid-state trajectories, temperature and host-solvent composition dominate the bulk-transport response, with FEC acting as a secondary modifier.
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All authors İpek Yenda Ç{\i}nar, Oguzhan Orhan, M. Oluş Özbek, Şener Özönder

High Energy Physics (Experiment)

Search for dark matter particle interactions in an extended nuclear recoil energy window with the LUX-ZEPLIN (LZ) experiment

D.S. Akerib, A.K. Al Musalhi, B.J. Almquist et al. (+214 more)

We report on a search for dark matter particles interacting with xenon nuclei in an exposure of 2.84 tonne-years with the LUX-ZEPLIN (LZ) experiment. An extended nuclear recoil energy window up to approximately 270 keV enables searches for effective field theory and inelastic models of dark matter where high-energy recoils account for a larger fraction of the predicted recoil spectrum compared to the nominal spin independent interaction. We observe one event with characteristics consistent with a nuclear recoil of $248\pm23\,\mathrm{(stat)}\pm23\,\mathrm{(sys)}$ keV, in a region where the known background expectation is low. A profile likelihood ratio test finds tension with the background-only hypothesis at a global significance of 2.6$\sigma$ when accounting for look-elsewhere effects, with a maximum local significance of 3.4$\sigma$ across the models tested. We describe the analysis and event of interest, the background model used in the statistical inference, and detail several of the rare background topologies considered.
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All authors D.S. Akerib, A.K. Al Musalhi, B.J. Almquist, C.S. Amarasinghe, A. Ames, T. Anderson, N. Angelides, H.M. Araújo, J.E. Armstrong, M. Arthurs, A. Baker, S. Balashov, J. Bang, J.W. Bargemann, E.E. Barillier, D. Bauer, K. Beattie, A. Beauchene, T.L. Benson, A. Bhatti, T.P. Biesiadzinski, H.J. Birch, E. Bishop, G.M. Blockinger, B. Boxer, C.A.J. Brew, P. Brás, S. Burdin, M.C. Carmona-Benitez, M. Carter, A. Chawla, J.J. Cherwinka, Y.T. Chin, S. Contreras, M.V. Converse, R. Coronel, A. Cottle, C. Coulson, G. Cox, C.E. Dahl, I. Darlington, S. Dave, J. Delgaudio, S. Desai, S. Dey, L. de Viveiros, L. Di Felice, C. Ding, J.E.Y. Dobson, E. Druszkiewicz, S. Dubey, C.L. Dunbar, S.R. Eriksen, S. Fayer, N. Fieldhouse, S. Fiorucci, H. Flaecher, E.D. Fraser, T.M.A. Fruth, P.W. Gaemers, R.J. Gaitskell, A. Geffre, J. Genovesi, C. Ghag, J. Ghamsari, A. Ghosh, S. Ghosh, R. Gibbons, S. Gokhale, J. Green, M.G.D.van der Grinten, J.J. Haiston, C.R. Hall, T. Hall, R.N. Hampp, S.J. Haselschwardt, M.A. Hernandez, S.A. Hertel, G.J. Homenides, M. Horn, T. Horoho, D.Q. Huang, W. Hulse, D. Hunt, E. Jacquet, R.S. James, K.R. Jenkins, A.C. Kaboth, A.C. Kamaha, D. Khaitan, A. Khazov, J. Kim, Y.D. Kim, D. Kodroff, Q.C. Kong, E.V. Korolkova, H. Kraus, S. Kravitz, L. Kreczko, V.A. Kudryavtsev, C. Lawes, E.B. Leon, D.S. Leonard, K.T. Lesko, C. Levy, Z. Li, J. Lin, A. Lindote, W.H. Lippincott, J. Long, M.I. Lopes, W. Lorenzon, C. Lu, S. Luitz, W. Ma, V. Mahajan, P.A. Majewski, A. Manalaysay, R.L. Mannino, R.J. Matheson, C. Maupin, M.E. McCarthy, D.N. McKinsey, J. McLaughlin, J.B. McLaughlin, B. Mitra, E. Mizrachi, M.E. Monzani, K. Morå, E. Morrison, B.J. Mount, J. Munski, M. Murdy, A.St.J. Murphy, H.N. Nelson, F. Neves, A. Nguyen, C.L. O'Brien, F.H. O'Shea, I. Olcina, K.C. Oliver-Mallory, J. Orpwood, K.Y Oyulmaz, K.J. Palladino, N.J. Pannifer, S.J. Patton, B. Penning, G. Pereira, R. Peres, E. Perry, T. Pershing, A. Piepke, S.S. Poudel, Y. Qie, J. Reichenbacher, G.R.C. Rischbieter, E. Ritchey, H.S. Riyat, R. Rosero, N.J. Rowe, T. Rushton, D. Rynders, S. Saltão, I. Sargeant, A.B.M.R. Sazzad, R.W. Schnee, G. Sehr, M. Severson B. Shafer, S. Shaw, L. Sherman, K. Shi, T. Shutt, C. Silva, G. Sinev, J. Siniscalco, A.M. Softley-Brown, V.N. Solovov, P. Sorensen, J. Soria, T.J. Sumner, M. Szydagis, C.F. Tang, K. Thieme, D.R. Tiedt, D.R. Tovey, J. Tranter, M. Trask, K. Trengove, B. Twigg, A. Usón, A.C. Vaitkus, O. Valentino, A. Wang, J.J. Wang, Y. Wang, L. Weeldreyer, T.J. Whitis, K. Wild, M. Williams, J. Winnicki, M.S. Witherell, L. Wolf, F.L.H. Wolfs, S. Woodford, D. Woodward, C.J. Wright, Q. Xia, J. Xu, Y. Xu, M. Yeh, D. Yeum, J. Young, H.D. Zenger, W. Zha, H. Zhang, T. Zhang, Y. Zhou

High Energy Physics (Theory)

Zero-damped modes of near-extremal Reissner–Nordström black holes from exact WKB

Prisco Lo Chiatto, Sebastian Schenk, Nils Wagner et al. (+1 more)

The late-time ringdown dynamics of near-extremal black holes (BHs) are expected to be dominated by zero-damped modes (ZDMs), whose decay rates are parametrically suppressed relative to those of ordinary quasinormal modes. In this paper, we demonstrate that exact WKB methods provide an exceptionally powerful framework for analyzing the ZDM spectrum of near-extremal Reissner–Nordström (RN) BHs. Focusing on massless, neutral scalar modes propagating on an RN background, we present the full Stokes geometry derived from the radial eigenvalue problem and establish the corresponding exact quantization condition (EQC). Our analytic computation of the Voros symbols entering the EQC achieves higher-order accuracy for the ZDM spectrum compared to previous studies and is systematically improvable. Ergo, this work serves as a proof of concept for investigations of ZDM spectra of other systems using exact WKB methods.
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All authors Prisco Lo Chiatto, Sebastian Schenk, Nils Wagner, Felix Yu

Mesoscale and Nanoscale Physics

Relaxation effects on Hartree-Fock ground states in twisted bilayer graphene at even integer fillings

Tianyu Kong, Alexander B. Watson, Lin Lin et al. (+2 more)

A standard approach for studying magic angle twisted bilayer graphene (MATBG)'s correlated electronic phase diagram is to project the Coulomb interaction down to effective models only involving electrons in single-particle flat bands and some nearby remote bands. We provide a novel systematic derivation of a single-particle continuum model of MATBG's single-particle properties which incorporates structural relaxation while remaining in the Lagrangian frame. We project the Coulomb interactions down to electrons occupying the flat bands of this model and compute the Hartree-Fock many-body ground states at fillings $\nu = \pm 2$. We find that incorporating relaxation effects drives the model into a semi-metallic phase at $- 2$ because of particle-hole asymmetry in the relaxed model's single-particle dispersion and because the flat band wavefunctions become more concentrated leading to an enhanced Hartree potential. Our results corroborate recent ab initio density functional theory studies which also found semi-metallic phases at $-2$. We discuss potential explanations for why such phases have not been seen in experiments.
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All authors Tianyu Kong, Alexander B. Watson, Lin Lin, Mitchell Luskin, Kevin D. Stubbs

High Energy Physics (Theory)

Scale-separated AdS$_2$ flux vacua from type II

George Tringas and Timm Wrase

Motivated by the question of whether the internal scales of a compactification can be parametrically decoupled from the external curvature scale, and by the possibility of probing such vacua holographically, we construct the first AdS$_2$ flux vacua with parametric scale separation. We compactify type II string theory on a $G_2$ structure orbifold times a circle in the presence of smeared spacetime-filling O1/O5-planes or O4/O8-planes, together with NSNS and RR fluxes. We derive the two-dimensional dilaton-gravity effective theory and exhibit families of vacua in which unbounded $F_5$ and $H_7$ fluxes provide parametric control in type IIB, while unbounded $F_4$, $F_8$, and $H_7$ fluxes provide parametric control in type IIA. For large flux quanta, the string coupling becomes parametrically weak, all internal bulk radii become parametrically large in string units, and the Kaluza–Klein scale separates from the $\mathrm{AdS}_2$ curvature scale. We analyze the ten-dimensional Killing-spinor equations and identify parametric branches preserving $\mathcal N=(1,1)$ supersymmetry in two dimensions. We explain how our geometrically scale-separated AdS$_2$ vacua are compatible with a recent no-go theorem for scale separation in theories with extended supersymmetry. Finally, we discuss various T-dualities leading to other type IIB and type IIA compactifications on $G_2$ structure spaces times a circle and $SU(3)$ structure spaces times a two-torus.
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High Energy Astrophysical Phenomena

17 Yr of Magnetar Bursts Observed with the Fermi Gamma-ray Burst Monitor

Matt Godwin, Özge Keskin, Mustafa Demirer et al. (+17 more)

The Fermi Gamma-ray Burst Monitor (GBM) has been in operation for over 17 years, during which it has observed more than a thousand bursts from soft gamma repeaters (SGRs), also known as magnetars. Serving as a laboratory for extreme physics, magnetars are a sub-family of neutron stars characterized by extreme magnetic field strength, observed through a combination of persistent and short transient emission across the electromagnetic spectrum. We present the comprehensive GBM catalog of SGR short bursts which supersedes the 5-year catalog of Collazzi et al. 2015. The new catalog contains 1254 SGR short bursts observed over 17 years, providing the longest uninterrupted, high-sensitivity all-sky monitoring of magnetar bursts with unprecedented spectral and temporal resolution. Our catalog contains bursts from 17 unique Galactic sources, with major contributions by bursts from SGR J1935+2154 and SGR J1550-5418. We present overall characteristics of these bursts, such as the durations, spectral parameters for various photon models, fluxes, as well as their comparison with recently published catalogs of other missions and the previous GBM magnetar catalog. The machine readable catalog, as well as burst spectra and response files are made publicly available for the community.
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All authors Matt Godwin, Özge Keskin, Mustafa Demirer, Yi-Jing Yi, Lin Lin, Oliver J. Roberts, Ersin Göğüş, Yuki Kaneko, Michael Briggs, Matthew G. Baring, Eric Burns, David M. Palmer, Boyan A. Hristov, Bagrat Mailyan, Christian Malacaria, Eva Palafox, Chryssa Kouveliotou, Alexander J. van der Horst, Peter Veres, George Younes

High Energy Physics (Phenomenology)

A Peccei-Quinn Origin for Inelastic Electroweak Dark Matter after LUX-ZEPLIN

Luca Visinelli

The LUX-ZEPLIN (LZ) experiment has reported a nuclear recoil event reconstructed at $E_R=248\pm23_{\rm stat}\pm23_{\rm sys}{\rm\,keV}$ in a dedicated high-recoil search. We investigate an inelastic electroweak (EW) doublet interpretation in which spontaneous Peccei-Quinn (PQ) breaking leaves a residual parity that stabilizes the lighter neutral state and generates its Majorana splitting. A PQ-charged singlet fermion acquires a Majorana mass from the PQ-breaking vacuum expectation value and, once integrated out, induces the dimension-five operator that splits a vectorlike EW doublet, while a minimal KSVZ sector supplies the QCD anomaly. For $v_S=4.4\times10^{11}{\rm\,GeV}$ and $M_N\simeq50{\rm\,TeV}$, the LZ-motivated splitting requires $y\simeq0.023$. In a standard thermal history, the EW doublet is subdominant. Three kinematic benchmarks with $M_D=297.0$, $396.4$, and $549.7{\rm\,GeV}$, $\delta_\chi\simeq304$-$343{\rm\,keV}$, and $\xi_\chi\simeq0.073$-$0.250$ each yield about one recoil event, while their accepted spectra peak below the observed recoil energy, so they are interpreted as kinematic rather than spectral best-fit points. The remaining abundance can be supplied by the QCD axion through vacuum misalignment. We recompute solar capture for the subdominant thermal WIMP component and compare the resulting annihilation signal with the IceCube $W^+W^-$ limit, finding the LZ-motivated standard-thermal branch excluded under the assumptions adopted here. The excited state has a millisecond-scale radiative lifetime and kilometer-scale decay length, leaving the LZ topology dominated by a single nuclear recoil while allowing complementary luminous signals after terrestrial upscattering.
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Plasma Physics

Global Gyrokinetic Simulations of Electromagnetic Turbulence in STEP

Daniel Kennedy, Facundo Sheffield, Tobias Görler et al. (+6 more)

This paper presents gradient-driven global electromagnetic gyrokinetic simulations for a conceptual burning flat-top operating point of STEP [1], STEP-EC-HD, and investigates how non-local effects influence the nonlinear saturation and transport of the electromagnetic turbulence at finite ${\beta}$. Local gyrokinetic simulations have shown that including ${\delta}B_{\parallel}$ is essential for the dominant hybrid kinetic ballooning modes, or hKBMs, to be unstable in STEP [2]. Using the long-wavelength ${\delta}B_{\parallel}$ solver [3] implemented in GENE [4], this work demonstrates that the linear mode spectrum can be accurately captured in global geometry, which results in good agreement with an ensemble of local flux-tube simulations. The global framework reproduces the hKBMs identified in [5], while microtearing modes remain challenging to resolve due to their shorter radial scales. Nonlinear simulations reveal clear evidence of an electromagnetic transition to states with extremely large heat fluxes, consistent with local simulations and with the predicted loss of zonal-flow regulation for this proposed operating point [6]. These findings establish the capability of global gyrokinetics to capture finite-${\beta}$ dynamics in STEP-like plasmas and motivate future work to identify the conditions governing this transition.
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All authors Daniel Kennedy, Facundo Sheffield, Tobias Görler, Colin Roach, Maurizio Giacomin, Arka Bokshi, David Dickinson, Harry Dudding, Bhavin Patel

Instrumentation and Methods for Astrophysics

GRINTA: a new Probe of the Dynamic Universe

Lorenzo Natalucci, Philippe Laurent, Marica Branchesi et al. (+48 more)

Recent observations of the transient sky at all wavelengths are increasingly revealing the importance of the multi-messenger and multi-wavelength approach. The GRINTA (Gamma-Ray INternational Transient Array Observatory) mission, proposed for launch around the middle of the next decade, is conceived as a small mission with good sensitivity, excellent angular resolution and fast follow-up capability for studying transient sources at timescales from ms to hours, at the same time ensuring optimal integration with multi-messenger networks. The GRINTA mission will carry two complementary payloads to cover in total the 5 keV-10 MeV band, that will detect and localise gamma-ray bursts covering $\sim$ half of the sky and will be able to perform imaging surveys with sub-arcmin resolution. GRINTA will operate in synergy with the most powerful electromagnetic, gravitational wave and neutrino observatories foreseen to be operational after 2035.
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All authors Lorenzo Natalucci, Philippe Laurent, Marica Branchesi, Mariateresa Fiocchi, Lorraine Hanlon, J. Miguel Mas-Hesse, Aline Meuris, Paul 'O Brien, James C. Rodi, Simone Scaringi, Konrad Skup, Norbert Werner, Silvia Zane, Julia Alfonso-Garzon, Biswajit Banerjee, Patrizia Barria, Anthony J.Bird, Soren Brandt, Gabriele Bruni, Floriane Cangemi, Gianluca Castignani, Eric Chassande-Mottin, Sylvain Chaty, Jerome Chenevez, Alexis Coleiro, Francesco Dazzi, Alessio L. De Santis, Phil Evans, Olivier Godet, Diego Gotz, Rene Hudec, Lucien Kuiper, Angela Malizia, Sheila McBreen, Sandro Mereghetti, Manuela Molina, Filip Munz, David Murphy, Gor Oganesyan, Francesca Panessa, Elena Pian, Jakub R{\i}pa, Oliver J. Roberts, Samuele Ronchini, Fabian Schussler, Vojtech Simon, Nial Tanvir, Alexey Uliyanov, Nello Vertolli, Stanislav V{\i}tek, Ugo Zannoni

Materials Science

First Principle Analysis of the Magnetism and Electronic Structure of Fe2XSi (X=Ti, V)

Hanieh Kachooee, Cindy Kim, Jason Carbajal et al. (+2 more)

The electronic, magnetic, and mechanical properties of Fe2XSi, where X is titanium (Ti) and vanadium (V), are investigated using computational methods. Volume optimization reveals that the ground state of Fe2TiSi is a nonmagnetic narrow-band gap semiconductor, and that of Fe2VSi is a ferrimagnetic metal. The negative formation energies of both materials confirm the stability of their crystal structures. Mechanical properties confirm the static stability of the crystal structure and suggest that the titanium compound is ductile; however, the vanadium material is brittle. Density of states and band structure studies confirm the nonmagnetic semiconducting nature with an indirect band gap at {\Gamma} and X for the titanium material and the ferrimagnetic-metallic nature of the vanadium material. Electronic and magnetic properties of the materials were investigated with applied tension (negative pressure) and compression (positive pressure) to the crystal structure. The pressure study on Fe2TiSi shows a tunable band gap and a possible semiconductor-metal transition, and Fe2VSi shows a tunable magnetic moment and a possible low-spin/high-spin magnetic transition.
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All authors Hanieh Kachooee, Cindy Kim, Jason Carbajal, K. Hettiarachchilage, N. Haldolaarachchige

Mathematical Physics · Cross-listed from math.OA

Noncommutative majorization

Matthew Kennedy and Paul Skoufranis

We introduce a theory of noncommutative majorization that extends the classical majorization theory introduced by Hardy, Littlewood and Pólya to tuples of self-adjoint matrices that do not necessarily commute. We define and characterize a noncommutative majorization order that extends the classical majorization order. The definition is in terms of convex noncommutative functions, and we utilize the noncommutative convexity theory and noncommutative Choquet theory recently introduced by Davidson and the first author. As an application, we obtain a new necessary and sufficient condition for the existence of a trace-preserving completely positive map, i.e. a quantum channel, that interpolates between two finite sets of matrices. We give examples demonstrating that it is not always possible for this map to be chosen mixed unitary, even locally. We also address the computational difficulty of verifying the noncommutative majorization order. Our results further apply beyond the tracial case, and we obtain more general results characterizing the existence of unital completely positive maps that preserve an arbitrary faithful state or even unital completely positive map.
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High Energy Physics (Phenomenology)

MadSpin2: automated spin-entangled decays of heavy resonances via the spin-density matrix formalism

Spyros Argyropoulos, Valentin Durupt and Olivier Mattelaer

The simulation of processes that contain multiple particles from the decay of unstable resonances becomes computationally challenging both at leading order and beyond. This paper presents MADSPIN2, a new version of MADSPIN, a dedicated tool tackling this problem, primarily for events generated with the MG5AMC event generator. While still based on the Frixione-Laenen-Motylinski-Webber formalism, the new version leverages spin-density matrices to lift most of the limitations of the previous implementation. It supports loop-induced processes, N -body decays and samples defined by amplitude-level interference between distinct hard-process amplitudes. It also introduces the multiple-pole approximation and a resonance-helicity decomposition, including off-diagonal helicity-interference contributions. These developments substantially broaden the phenomenological scope of MADSPIN, enabling applications that were previously inaccessible within the framework, several of which are demonstrated in this work.
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Quantum Physics

Variational preparation of thermofield double states for SYK models via multi-angle QAOA: sequential angle pruning for circuit reduction

Haji Muhammad Husnain Ashfaq, Moongul Byun and Keun-Young Kim

Variational preparation of thermofield double (TFD) states can require deep quantum circuits, particularly for interacting many-body systems. Reducing these circuits while retaining high fidelity is therefore crucial for TFD-state preparation on noisy quantum processors. We study this problem by applying the multi-angle quantum approximate optimization algorithm (ma-QAOA) to TFD-state preparation and introducing two top-down sequential angle-pruning algorithms. Starting from the optimized initial ma-QAOA circuit, both algorithms sequentially remove Pauli-string evolutions with small optimized angles and reoptimize the remaining parameters after each removal. We apply these algorithms to Gaussian and binary Sachdev–Ye–Kitaev (SYK) models in both dense and sparse cases. We find that ma-QAOA prepares the target TFD states with high fidelity and that sequential small-angle pruning retains high fidelity while reducing the circuit depth, particularly at low temperature. Moreover, using the post-reoptimization cost in sequential small-angle pruning further improves the fidelity. For the binary sparse $N=10$ SYK model at $\beta=10$, $88.8\%$–$92.1\%$ of the nonlocal Pauli-string evolutions are removed while retaining an average fidelity of approximately $95\%$. Finally, we propose extensions of the sequential pruning algorithms toward quantum–classical hybrid implementation.
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Quantum Physics

Phonon-limited detection thresholds for genetically encoded fluorescent-protein spin-qubit relaxometry of neural radicals

Parul Raghuvanshi, Sagnik Ganguly, Sharika E et al. (+2 more)

The demonstration that enhanced yellow fluorescent protein hosts an optically addressable spin-1 qubit in its metastable triplet state raises the prospect of genetically encoded quantum sensing at molecular length scales. We develop a detection-limit theory for using this fluorescent-protein spin qubit (FPSQ) to sense paramagnetic neural signaling radicals by spin relaxometry. We derive the transition-resolved Redfield relaxation matrix of the zero-field-split triplet coupled to a diffusing radical bath, establish the regime in which it collapses to a single exponential, and validate it against Lindblad simulations and nitrogen-vacancy benchmarks. Propagating the effects of photon shot noise, photobleaching-grounded photon budget, and finite measurement bandwidth, we find that the native room-temperature sensor falls short of physiological sensitivity by six to eight orders of magnitude with the bottleneck being the phonon-limited intrinsic $\Tone$. Analyzing the underlying direct and two-phonon Raman processes, we show that room-temperature relaxation is Raman-dominated by $\sim\!720\!:\!1$ and that, because the Raman coefficient scales as $v^{-10}$ with sound velocity, a $\sim\!2\times$ stiffening of the chromophore environment recovers $\Tone\sim\SI{100}{\micro\second}$, sufficient for micromolar sensing. Nanomolar sensing is obstructed by a direct-process ceiling of \SI{79}{\micro\second} that vibronic decoupling alone cannot breach. We obtain quantitative design rules, identify photon yield as a co-equal bottleneck, and propose a frequency-resolved protocol for chemical specificity.
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All authors Parul Raghuvanshi, Sagnik Ganguly, Sharika E, Mohana Priya T., Vishvendra S. Poonia

High Energy Physics (Phenomenology)

The $H^*H^*V$ couplings from light-cone sum rules

Chao Wang

We present a determination of the strong charge couplings $g_{H^*H^*V}$ and magnetic couplings $f_{H^*H^*V}$ (with $H \in \{D, B\}$ and $V \in \{\rho, \omega, K^*, \phi\}$) using the framework of light-cone sum rules (LCSR). The theoretical precision is improved by establishing the leading-power hard-collinear factorization formulas with next-to-leading-order (NLO) $\alpha_s$ corrections, alongside the inclusion of power-suppressed contributions up to the next-to-next-to-leading power (NNLP) for both channels. By parameterizing the $\mathcal{O}(1/m_{H^*})$ power corrections, we extract the universal static couplings $\beta = 0.73 \pm 0.13$ and $\hat{\lambda} = 0.23 \pm 0.06 \text{ GeV}^{-1}$, highlighting their distinct heavy-quark scaling behaviors. While our investigation into SU(3) flavor symmetry breaking shows that these effects are currently overwhelmed by uncertainties in the non-perturbative vector meson distribution amplitudes, our determinations of these spin-conserving and spin-flip parameters provide non-perturbative inputs for modeling the S-wave central potentials, as well as the tensor forces and D-wave mixing effects, in exotic heavy tetraquarks.
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Quantum Physics

Information and reference requirements for auditing collider classifiers

Roberto Fernández-Barrios, Iker Pastor-López, Asier González-Santocildes et al. (+1 more)

Assertions about collider classifiers require observable evidence and a specified deployment reference. We distinguish the classification threshold that selects events from the claim threshold that defines acceptable performance. For fixed nominal-weighted ratio claims on a frozen finite population, we apply established assorter reductions and bounded-mean confidence sequences under independent sampling with replacement and a predeclared weight bound. The anytime-valid error control is per claim, not automatically simultaneous across claims, and is not a new statistical guarantee. In 19,680 archived paired audit-stream comparisons, changing unweighted correctness and its source reference to nominal-weighted accuracy and its own reference changed 536 supported verdicts to unresolved and 226 in the reverse direction. Scores, labels, weights and exact ratios were available before these simulated audits; their stopping times demonstrate no operational acquisition saving. A post hoc analysis of 30 finite-shot quantum-kernel realizations, with paired RAW and diagonal-loading treatments, describes sensitivity to operating rules, ideal versus realized references, and fixed versus recomposed margin groups. Verdict differences are not auditor error rates, and no quantum-specific mechanism or quantum advantage is established. A CMS open-data example supports restricted aggregate statements while event-level accuracy remains unidentified. This substantial revision withdraws the previous physical-interval coverage conclusions following numerical-validation problems; the available reevaluation does not reestablish them. The retained contribution is mathematical exposition and descriptive evidence, without methodological-priority or calibrated physical-inference claims.
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All authors Roberto Fernández-Barrios, Iker Pastor-López, Asier González-Santocildes, Pablo García Bringas

2609.02781 · 2 Sep · 14 pages, 0 figures, 2 tables; separate 10-page Supplementary Material (S1–S9, 4 tables) provided as an ancillary PDF. Title changed. Substantial corrective revision: previous physical-interval coverage conclusions withdrawn after numerical-validation problems were identified; methodological attribution and scope revised; descriptive classifier results retained

Abstract PDF $QNTM ×3$CLDR ×2$AUDIT ×1