Wed·Jan 21, 2026Wednesday·January 21, 2026

1. 01*

   An upper limit on cosmological chiral gravitational wave background

   Mohammad Ali Gorji🇰🇷 · Ashu Kushwaha🇯🇵 · Teruaki Suyama🇯🇵

   Within the standard framework in which electroweak sphaleron processes relate lepton and baryon number, we derive an upper limit on the amplitude of a chiral gravitational wave background produced prior to the electroweak epoch. This bound is independent of the production time of chiral GWs for superhorizon modes, while it becomes sensitive to the production time for subhorizon modes. For sufficiently high reheating temperatures, the bound becomes significantly more stringent than the conventional big bang nucleosynthesis constraints at frequencies above the MHz scale, thereby providing a powerful and \emph{model-independent} probe of parity-violating physics in the early Universe.

   hep-phastro-ph.COgr-qchep-thPRD(2026)·1 citation
2. 02*

   On the real part of elastic scattering amplitude

   S.M. Troshin🇷🇺 · N.E. Tyurin🇷🇺

   We discuss dominance of imaginary part of the elastic scattering amplitude and argue in favor of approximation based on this dominance.

   hep-phhep-exModern Physics Letters A (2026) 2650172 (…·1 citation
3. 03*

   Non-perturbative flavor asymmetry in the nucleon and deuteron: The light-front Hamiltonian effective field theory approach

   Xianghui Cao🇨🇳 · Shan Cheng🇨🇳 · Yihan Duan🇨🇳 · Yang Li🇨🇳 · Siqi Xu🇨🇳 · Xingbo Zhao🇨🇳

   We investigate non-perturbative multi-pion contributions to nucleon flavor asymmetry within the framework of Light-Front Hamiltonian Effective Field Theory (LFHEFT). Utilizing a Fock sector expansion, we systematically incorporate pionic degrees of freedom, with the nucleon-pion interactions governed by a scalar variant of chiral effective field theory. Our results demonstrate that the non-perturbatively calculated longitudinal momentum distributions exhibit significant deviations from leading-order perturbative predictions, emphasizing the importance of higher-order Fock components in describing the proton's sea quark structure. Furthermore, we demonstrate the feasibility of extending this framework to investigate nuclear effects in light nuclei, such as the deuteron. This unified approach provides a consistent basis for analyzing the interplay between intrinsic nucleon structure and nuclear modifications, potentially offering new insights into the flavor asymmetry observed in fixed-target and collider experiments.

   hep-phnucl-thJ.Subatomic Part.Cosmol.(2026)·0 citations
4. 04*

   Enhanced sensitivity to the $H\to Z\gamma \to {\ell }^{+}{\ell }^{-}\gamma$ decay at the LHC using machine learning and novel kinematic observables

   Manisha Kumari🇮🇳 · Amal Sarkar🇮🇳

   At LHC energies, the Drell--Yan ($Z/{\gamma }^{\ast }$) processes have a substantially large cross section. Their di-lepton (${\ell }^{+}{\ell }^{-}$) final state contributes significantly to many resonant signal regions, making them one of the dominant backgrounds in numerous physics analyses. The study focuses on improving the discrimination and suppression of the $Z/{\gamma }^{\ast }\to {\ell }^{+}{\ell }^{-}$ background from the $H\to Z\gamma \to {\ell }^{+}{\ell }^{-}\gamma$ signal at $\sqrt{s}=13\text{TeV}$ by leveraging Monte Carlo simulated data. The analysis introduces physics-motivated correlated observables derived from the two-dimensional $(P_{\mathrm{Higgs}},{\theta }_{Z\gamma })$ plane. These observables encode differences in angular and momentum information to enhance signal--background separation while maintaining high signal efficiency. We present a multivariate analysis (MVA) employing a Boosted Decision Tree (XGBoost) classifier. By incorporating additional physics-motivated correlated observables, the classifier achieves measurable improvements in performance. A significant increase in the area under the ROC curve (AUC) is observed in both the electron and muon channels, demonstrating the effectiveness of the expanded feature set. Further, optimised background rejection using $(P_{\mathrm{Higgs}},{\theta }_{Z\gamma })$ plane increases the signal-to-background ratio to 2.1\% and 3.4\% for the electron and muon channel respectively near the Higgs mass. This work demonstrates that combining kinematic correlations with interpretable multivariate techniques leads to improved sensitivity and robust background rejection. The approach is flexible and can be readily applied to a wide range of analyses, including rare Higgs decays, resonant searches, and studies beyond the Standard Model.

   hep-phJHEP(2026)·0 citations
5. 05*

   The dynamically generated $N(1535)$ state in the ${\Lambda }_c^{+}\to p{\bar{K}}^0{\pi }^0$ decay

   Ying Li🇨🇳 · En Wang🇨🇳 · Li-Sheng Geng🇨🇳 · Ju-Jun Xie🇨🇳

   We present a theoretical analysis of the process ${\Lambda }_c^{+}\to p{\bar{K}}^0{\pi }^0$ within the chiral unitary approach, with particular emphasis on the dynamically generated $N(1535)$ resonance. In addition to $N(1535)$, our model incorporates contributions from other intermediate resonances including $N(1650)$, $K^{\ast }(892)$, $K_0^{\ast }(1430)$, $N(1440)$, and $\Sigma (1750)$. The calculated invariant mass distributions and Dalitz plot are in good agreement with the recent Belle measurements. Our analysis highlights the crucial role of $N(1535)$ state in this decay channel and supports its interpretation as a dynamically generated state arising from coupled-channel meson-baryon interactions.

   hep-phPRD(2026)·5 citations
6. 06*

   Quantum Encoding Framework for Leptophilic Gauge Theories

   S. O. Kara🇹🇷

   We present a systematic quantum encoding framework for leptophilic extensions of the Standard Model, tailored to quantum simulation applications on near term and future quantum devices. Focusing on anomaly free $U(1{)}_{\ell }^{\prime }$ gauge theories, we show that the leptonic charge structure admits a natural and scalable representation on qubit registers, where gauge symmetries and anomaly cancellation conditions are enforced directly at the level of quantum states. Within this framework, gauge invariant operators are mapped to unitary quantum circuits, ensuring the preservation of gauge symmetry under quantum evolution. As a proof of principle, we construct explicit circuits that encode scattering processes mediated by a leptophilic gauge boson $Z_{\ell }^{\prime }$. Our results establish a reusable bridge between beyond the Standard Model gauge theories and quantum information science, providing a concrete pathway for simulating leptophilic gauge sectors within emerging quantum computing architectures.

   hep-ph0 citations
7. 07*

   Structure of Bound States with Coulomb plus Short-range Interaction

   Chisato Uno🇯🇵 · Tetsuo Hyodo🇯🇵

   We study the structure of bound states appearing in systems governed by the Coulomb and short-range interactions. We analyze the binding energies and wave functions of the bound states generated by the Coulomb plus short-range potential. We demonstrate that Coulomb-induced shifts of the binding energy are closely correlated with the spatial distribution of the wave function. Furthermore, we show that the asymptotic behavior of wave functions of weakly bound states is qualitatively altered by Coulomb repulsion, leading to a modification of the near-threshold mass scaling that is otherwise universal for short-range interactions.

   hep-phnucl-th0 citations
8. 08*

   The dynamically generated $h_1$ state by the $K^{\ast }{\bar{K}}^{\ast }$ interaction and its $K_1(1270)\bar{K}$ and $b_1(1235)\pi$ decays

   Qing-Hua Shen🇨🇳 · Li-Sheng Geng🇨🇳 · Xiang Liu🇨🇳 · Ju-Jun Xie🇨🇳

   We investigate the dynamically generated $h_1$ state with spin-parity $J^P=1^{+}$ and a mass around 1790~MeV, arising from the $K^{\ast }{\bar{K}}^{\ast }$ interaction within the chiral unitary approach. The partial decay widths into the $K_1(1270)\bar{K}$ and $b_1(1235)\pi$ channels are calculated via a triangular loop mechanism. In this mechanism, the $h_1$ state couples to $K^{\ast }{\bar{K}}^{\ast }$, and final-state interactions between $K^{\ast }$ and ${\bar{K}}^{\ast }$ proceed through pseudoscalar-meson exchange, leading to the final states $\bar{K}$ (or $\pi$) and $K_1(1270)$ [or $b_1(1235)$]. We also present the invariant mass distributions of a vector meson and a pseudoscalar meson originating from the decays of $K_1(1270)$ or $b_1(1235)$, along with the corresponding decay widths. Our results show that these decay widths are all of the order of a few MeV. We hope that future experiments can test the predictions presented here, thereby helping to identify this $h_1$ state.

   hep-phPRD(2026)·0 citations
9. 09*

   $\gamma \mathbf{Z}$ Box at Low Energy

   Balma Duch🇪🇸 · Pere Masjuan🇪🇸 · Hubert Spiesberger🇩🇪

   We calculate the 1-loop $\gamma Z$ box-graph correction to electron-quark scattering at low energy and low momentum transfer. Both electron and quark masses are kept non-zero. From our result, we extract coupling constants for the low-energy effective Lagrangian with parity-violating 4-fermion interaction terms. We study the zero-mass limits and show that a non-zero electron mass is sufficient to obtain finite, well-defined couplings which are insensitive to a hadronic mass cutoff. We finally discuss the impact of our results on the determination of the weak charge of the proton from polarized electron-proton scattering.

   hep-phhep-latnucl-th1 citation
10. 10*

    The Dead Cone Effect in Heavy-Quark Jets: A Unified Study from Charm and Bottom to Top

    Redamy Perez-Ramos🇫🇷 · Stefan Kluth🇩🇪 · Wolfgang Ochs🇩🇪

    We present a unified overview of recent progress in the study of QCD radiation in heavy-quark jets, focusing on the dead-cone effect. Using precision data from LEP at $\sqrt{s}=91.2$~GeV, we demonstrate strong momentum-space suppression in charm and bottom quark jets, supported by Monte Carlo simulations with \textsc{Pythia}8, and provide a quantitative interpretation within the Modified Leading Logarithmic Approximation (MLLA) of perturbative QCD. We then extend the analysis to top-quark jets at $\sqrt{s}=1$~TeV, where finite lifetime effects and decay radiation introduce new conceptual challenges. A new method is presented to isolate the top-quark dead cone by separating production and decay radiation, and it is validated at both parton and hadron level using \textsc{Pythia}8. Together, these results establish a coherent framework for testing QCD radiation dynamics across all three heavy quarks.

    hep-phhep-ex0 citations
11. 11*

    The gradient-flow coupling of three-and four-dimensional QED

    Lars Georg🇩🇪 · Robert V. Harlander🇩🇪 · Robert H. Mason🇩🇪

    We evaluate the QED coupling in the gradient-flow scheme in three and four space-time dimensions. Our general result applies to any theory with a U(1) gauge field coupled to arbitary other fields via arbitrary interactions. As an example, we consider QED with $n_{\text{f}}$ flavors in three and four space-time dimensions and evaluate the corresponding $\beta$ functions. In four dimensions, we find that the perturbative expansion of the $\beta$ function behaves much better than the corresponding expression in QCD. In three dimensions, we recover both the ultraviolet as well as the infrared fixed points of the QED coupling in the large-$n_{\text{f}}$ limit.

    hep-phhep-latPRD(2026)·2 citations
12. 12*

    Mineral Detection of Cosmic-Ray Boosted Dark Matter

    Jin-Wei Wang🇨🇳 · Fei-Fei Li🇨🇳

    We present the first dedicated analysis of cosmic-ray boosted dark matter (CRDM) in paleo detectors. Owing to their large kinetic energies, CRDM particles generate nuclear-recoil tracks that extend to substantially larger lengths than those produced by dominant backgrounds from neutrinos and intrinsic radioactivity. Combined with the ultra-large effective geological exposure of $\mathcal{O}(10^5)\mathrm{t}\mathrm{yr}$, paleo detectors provide a uniquely sensitive probe of sub-GeV DM. Considering both constant and vector-mediator interactions, we find that paleo detectors improve the sensitivity to the DM--proton scattering cross section by one to two orders of magnitude compared with the latest XENONnT limits.

    hep-ph5 citations
13. 13*

    Frame Dependence in Generalized Chiral Kinetic Theory

    Shu-Xiang Ma🇨🇳 · Jian-Hua Gao🇨🇳

    We investigate the frame dependence of distribution functions within the framework of generalized chiral kinetic theory. Based on the derived transformation rules governing the choice of frame, we analytically obtain the global equilibrium solution in the presence of vorticity and electromagnetic fields. Our results show that, under the assumption of a varying electromagnetic field, these equilibrium solutions can be uniquely determined.

    hep-phhep-thnucl-thCPC(2026)·0 citations
14. 14*

    Systematic study of lepton-flavor-violating dark matter interactions via indirect detection in effective field theories

    Sahabub Jahedi🇨🇳 · Jin-Han Liang🇨🇳 · Yi Liao🇨🇳 · Xiao-Dong Ma🇨🇳 · Yoshiki Uchida🇨🇳

    Lepton-flavor-violating (LFV) interactions involving dark matter (DM) particles remain a largely unexplored area. In this study, we systematically investigate LFV DM interactions within the framework of effective field theories by analyzing astrophysical photons and positrons produced from DM annihilation. Employing the astrophysical photon and positron data collected by Fermi-LAT, INTEGRAL, XMM-Newton, and AMS-02, we place meaningful constraints on all leading-order effective operators involving a DM pair and a flavor-violating charged lepton pair. Our analysis covers the three well-known DM candidates: a scalar, a fermion, and a vector particle. For the photon flux, we consider contributions from final-state radiation, radiative decay, and inverse Compton scattering and examine their respective sensitivity regions across different DM masses and photon energies. We find that, for DM masses below $\mathcal{O}(20\mathrm{GeV})$, INTEGRAL provides the most stringent constraints on annihilation cross sections and effective operators in all three LFV channels, whereas AMS-02 offers the strongest constraints above $\mathcal{O}(20\mathrm{GeV})$.

    hep-phPRD(2026)·1 citation
15. 15*

    The Simplest B Decay, Precisely

    Claudia Cornella🇨🇭 · Max Ferré🇩🇪 · Matthias König🇩🇪 · Matthias Neubert🇺🇸

    We derive the QCD$\times$QED factorization theorem governing the leptonic decay $B^{-}\to {\mu }^{-}{\bar{\nu }}_{\mu }(\gamma )$ at all orders in ${\alpha }_s$ and $\alpha$. Electromagnetic corrections to this decay probe multiple scales, which we disentangle through a sequence of effective field theories (EFTs). The resulting state-of-the-art prediction for the photon-vetoed rate includes the complete structure-dependent component and is accurate at the percent level, establishing the theoretical framework required for future high-precision measurements of this channel, which will allow for a clean determination of $|V_{ub}|$ and powerful tests of new physics. Our work presents the first complete study of QED effects to an exclusive $B$-meson decay at next-to-leading power (NLP) in the heavy-quark expansion. Important milestones are (i) the construction of the complete NLP operator basis in soft-collinear effective theory (SCET); (ii) the proposal of a "SCET-friendly" reduction scheme for the Dirac structures of four-fermion operators in dimensional regularization, which avoids power-enhanced evanescent operators; (iii) the consistent refactorization of endpoint-divergent convolution integrals and the first complete resummation of "rapidity logarithms" arising at the boundary between the contributions involving soft and hard-collinear quarks; (iv) the systematic discussion of the EFT below the scale of QCD confinement and the non-perturbative matching of SCET onto this low-energy theory; (v) the decoupling of pseudoscalar mesons in the context of heavy-hadron chiral perturbation theory, so that they can be integrated out for processes in which they do not appear as external particles. We perform a phenomenological analysis of direct and indirect contributions to the decay rate and radiation-energy spectrum, highlighting the importance of the chiral anomaly.

    hep-phJHEP(2026)·9 citations
16. 16*

    Gravitational Waves and Primordial Black Holes produced by Dark Meta Stable Vacuum Decay

    Haipeng An🇨🇳 · Tingyu Li🇨🇳 · Chen Yang🇨🇳

    Inspired by string theory and cosmological constant problem, it is plausible that the Universe's vacuum structure is characterized by a landscape of metastable vacua. The existence of dark matter and dark energy further suggests that the dark sector may inhabit its own "dark landscape". If the dark vacuum is metastable, bubbles of lower-energy phases can nucleate at an approximately constant rate. Because the Hubble expansion rate is monotonically non-increasing with cosmic time, such nucleation can eventually lead to percolation and completion of a dark-sector phase transition. In this work, we investigate the phenomenological consequences of this transition, focusing on the resulting stochastic gravitational-wave background and the potential formation of primordial black holes. We find that the gravitational wave spectrum peaks at $k_{\mathrm{peak}}=3.1H_{\mathrm{PT}}$, with an amplitude ${\Omega }_{\mathrm{GW}}^{\mathrm{peak}}\simeq 1.5{\Omega }_{\gamma }(\Delta \rho /{\rho }_{\mathrm{tot}}{)}^2$. Furthermore, the formation of primordial black holes is suppressed due to $\Delta N_{\mathrm{eff}}$ constraint.

    hep-phastro-ph.COJHEP(2026)·6 citations
17. 17*

    Neutrino Masses with Enhanced $B-L$ Symmetry

    Xiyuan Gao🇩🇪 · Amir N. Khan🇩🇪

    Assuming all three known neutrinos are Dirac fermions, $U(1{)}_{B-L}$ can be an exact symmetry. We show that, if the condition of charge quantization is relaxed, the anomaly-free $B-L$ charges of two out of three right-handed neutrinos can be enhanced by arbitrarily large factors, while all other fermions retain their canonical charges. We call this setup as `enhanced $B-L$ symmetry' and promote it to be local. As long as this enhanced $B-L$ gauge symmetry remains unbroken, neutrinos stay chiral and massless at low energies. Nonzero neutrino masses then require sub-eV-scale symmetry breaking order parameters, which we associate with gravity-induced neutrino condensate. If the enhancement is large and the $B-L$ gauge boson $A^{\prime }$ is lighter than the heaviest neutrino, then the neutrino decay into $A^{\prime }$ directly constrains the gauge coupling, which can be significantly stronger than the baryon-based fifth-force tests. Through kinetic mixing with the photon, $A^{\prime }$ can also mediate neutrino-electron and coherent neutrino-nucleus scatterings, leading to possible signatures in neutrino observatories and dark matter detectors.

    hep-phgr-qc1 citation
18. 18*

    Emergent Large Lepton Mixing from Neutrino Refraction in Dark Matter

    Susobhan Chattopadhyay🇮🇳 · Yuber F. Perez-Gonzalez🇪🇸 · Manibrata Sen🇮🇳

    We propose a novel origin for the disparity between quark and lepton flavor mixing based on the refractive nature of neutrino masses. We postulate that the fundamental mixing in both the quark and lepton sectors is CKM-like, together with tiny vacuum neutrino masses, while the observed PMNS mixing matrix emerges dynamically from coherent forward scattering of neutrinos on an ultralight dark matter background. The resulting in-medium Hamiltonian rotates CKM mixing angles into large effective lepton mixings, naturally realizing quark--lepton complementarity without invoking new flavor symmetries. This framework links neutrino mass generation, flavor mixing, and dark matter, and predicts environment-dependent neutrino oscillation effects testable in current and future experiments.

    hep-phastro-ph.COhep-ex1 citation
19. 19*

    Constraints on Loryons in a Two Higgs Doublet Model

    Can Kilic🇺🇸 · Sanjay Mathai🇺🇸 · Taewook Youn🇺🇸

    We consider Loryons, particles beyond the Standard Model that receive a significant fraction of their masses from electroweak symmetry breaking, in the context of a two Higgs doublet model. Using scalar Loryons in the $[1,1]$, $[1,3]$ (as well as the equivalent $[3,1]$) and the $[2,2]$ representations of the custodial $SU(2{)}_L\times SU(2{)}_R$ global symmetry as benchmarks, we study the constraints on the Loryon parameter space, focusing on unitarity, Higgs decay observables, and the absence of Loryon vacuum expectation values. We find that while neutral singlet Loryons remain viable for masses up to 700 GeV, representations containing charged scalars are severely constrained by LHC data, particularly as the fraction of mass generated by symmetry breaking increases.

    hep-phJHEP(2026)·2 citations
20. 20*

    Trace Anomaly of Cold Dense Matter Constrained by Collective Flow

    Bao-An Li🇺🇸

    The trace anomaly of dense matter, $\Delta \equiv 1/3-P/\epsilon$, defined through the ratio $w\equiv P/\epsilon$ of pressure $P$ to energy density $\epsilon$, quantifies deviations from conformal symmetry and provides a dimensionless measure of the stiffness of the equation of state (EOS) relevant for both neutron stars and heavy-ion collisions. While $\Delta (\epsilon )$ has recently been inferred from neutron star observations, we report the first Bayesian extraction of the trace anomaly from collective flow observables in intermediate-energy heavy-ion collisions. By employing transport-model simulations that explicitly decouple the cold matter mean-field potential from thermal effects, we directly constrain the EOS of cold dense matter. Remarkably, the trace anomaly inferred from laboratory flow data agrees quantitatively, within $68\%$ credible intervals, with independent astrophysical posterior bands. This nontrivial agreement demonstrates that heavy-ion collisions and neutron star observations probe the same macroscopic properties in a mutually consistent way, establishing the dense-matter trace anomaly as a composition-insensitive macroscopic bridge observable across widely different physical environments.

    ↳ nucl-thastro-ph.HEhep-phnucl-exPRL(2026)·8 citations
21. 21*

    Quantum Qualifiers for Neural Network Model Selection in Hadronic Physics

    Brandon B. Le🇺🇸 · D. Keller🇺🇸

    As quantum machine-learning architectures mature, a central challenge is no longer their construction, but identifying the regimes in which they offer practical advantages over classical approaches. In this work, we introduce a framework for addressing this question in data-driven hadronic physics problems by developing diagnostic tools - centered on a quantitative quantum qualifier - that guide model selection between classical and quantum deep neural networks based on intrinsic properties of the data. Using controlled classification and regression studies, we show how relative model performance follows systematic trends in complexity, noise, and dimensionality, and how these trends can be distilled into a predictive criterion. We then demonstrate the utility of this approach through an application to Compton form factor extraction from deeply virtual Compton scattering, where the quantum qualifier identifies kinematic regimes favorable to quantum models. Together, these results establish a principled framework for deploying quantum machine-learning tools in precision hadronic physics.

    ↳ cs.LGhep-phnucl-thquant-ph1 citation
22. 22*

    Joint constraints on cosmic birefringence and early dark energy from ACT, Planck, DESI, and PantheonPlus

    Lu Yin🇨🇳 · Guo-Hong Du🇺🇸 · Tian-Nuo Li🇺🇸 · Xin Zhang🇺🇸

    With the increasing number of high-precision astronomical observations, physical quantities that were previously inaccessible to accurate calculations, such as cosmic birefringence, have once again become a focal point of interest. Such phenomena induce a nonvanishing cross-correlation between the $E$- and $B$-mode polarizations of the cosmic microwave background (CMB), thereby providing a direct observational signature of parity violation. The Chern-Simons coupling between the scalar field in early dark energy (EDE) models and CMB photons is regarded as a plausible mechanism for generating cosmic birefringence. Recent data from the Atacama Cosmology Telescope (ACT) deliver $EB$ measurements at higher multipole moments than those previously achieved by {Planck}, while DESI and PantheonPlus datasets provide new and stringent constraints on the late-time expansion history. Using a joint analysis of {Planck}, DESI DR1, Pantheon+, and ACT data, we perform a full-parameter constraint on the cosmic birefringence effects induced by the EDE-CMB photon coupling. Our results favor a higher Hubble constant, $H_0=76.9_{-2.5}^{+2.9}\mathrm{km}{\mathrm{s}}^{-1}\mathrm{Mp}{\mathrm{c}}^{-1}$, and a relatively large EDE fraction, $f_{\mathrm{EDE}}=0.232_{-0.047}^{+0.074}$. By comparing the cosmological evolution of this model across different data combinations, we find that the ACT-$EB$ data combined with {Planck} + DESI + PantheonPlus provide good constraints to both early- and late-Universe observations.

    ↳ astro-ph.COgr-qchep-phhep-th12 citations
23. 23*

    Rotational enhancement and stability of protoquark stars during thermal evolution

    Adamu Issifu🇧🇷 · Andreas Konstantinou🇨🇾 · Prashant Thakur🇰🇷 · Tobias Frederico🇧🇷

    We present the first systematic study of rigidly rotating protoquark stars based on isentropic equations of state (EOS) within the density-dependent quark mass (DDQM) framework. Using a quasi-static equilibrium approach, we follow the Kelvin--Helmholtz evolution from hot, lepton-rich matter to a cold, catalyzed quark star (QS). Rotation substantially enhances the maximum stable mass (by up to $\sim 40\%$), equatorial radius, and key rotational observables, with the ratio of rotational kinetic to gravitational potential energy, $T_{\mathrm{kin}}/|W|$, reaching $0.18$--$0.19$ near the Keplerian limit, indicating a heightened susceptibility to gravitational-wave--emitting instabilities. Thermal evolution introduces a clear ordering: all stellar properties peak during the lepton-rich stages and decrease monotonically as the star cools. Compared to hadronic stars, rotating proto-QSs exhibit larger radii, higher moments of inertia, and stronger quadrupolar deformation, producing a distinct signature in the mass--radius--spin plane. The EOS parameters are constrained using current astrophysical observations, including mass--radius measurements from HESS~J1731--347 and PSR~J0030+0451, the high-mass constraint from PSR~J0740+6620, and mass-radius constraints inferred from GW170817. The results demonstrate that future multimessenger observations must account for both thermal history and rotation to identify quark matter (QM) in compact stars robustly.

    ↳ astro-ph.HEhep-phnucl-thPRD(2026)·0 citations
24. 24*

    Angular-resolved nonlinear optical response as a probe of Lorentz violation in noncentrosymmetric materials

    Guilherme J. Inacio🇧🇷 · Nathanael N. Batista🇧🇷 · Wesley Spalenza🇧🇷 · Humberto Belich🇧🇷 · Juan José Palacios🇪🇸 · Wendel S. Paz🇧🇷

    We propose a methodology to detect weak Lorentz-violating (LV) backgrounds through the nonlinear shift photocurrent in noncentrosymmetric crystals. Using a spinful Rice--Mele model, we show that a LV background induces a momentum-odd correction to the Bloch Hamiltonian that reshapes the phase of the interband dipole matrix elements. As a result, the shift conductivity develops a robust $\pi$-periodic modulation as a function of the angle of a perpendicularly applied static electric field, in contrast to a weakly $2\pi$-periodic response of the Lorentz-symmetric case. This change in angular periodicity provides a signature of LV effects which can be directly identified through a photocurrent measurement. For realistic optical intensities, the predicted signal lies in the picoampere range, which can be enhanced in a matrix of weakly interacting chains, allowing sensitivity to LV coupling strengths of the order of $\xi \sim 10^{-24}\mathrm{C}\mathrm{m}$. These results establish nonlinear optical transport as a viable probe of emergent LV effects in solid-state systems.

    ↳ cond-mat.mes-hallhep-ph0 citations
25. 25*

    Decoupling of large-scale, adiabatic inflationary perturbations from enhanced small-scale modes at one-loop

    Laura Iacconi🇬🇧 · David Mulryne🇬🇧 · David Seery🇬🇧

    We reconsider back-reaction from large amplitude, short-scale perturbations onto a long wavelength adiabatic mode. In a loop expansion of the long-mode power spectrum, this back-reaction appears first at 1-loop. Due to the separation between the long and short scales, the separate universe method provides a simple and efficient framework for this computation. In this paper, building on our earlier work, we employ a $\delta N$ formula for the long mode, which captures the effect of short scales. We show that back-reaction at 1-loop is due to either (i) non-linearity of the $\delta N$ formula, or (ii) 1-loop corrections to the initial conditions. We argue that contributions of type (ii) cannot themselves be described within the separate universe framework, but their properties can be constrained using soft theorems and a ''multi-point propagator'' expansion. When applied to a band of enhanced short-scale perturbations that crossed the horizon during inflation, our result shows that the loop correction decouples from their detailed properties. Furthermore, the back-reaction we obtain is scale-invariant. Its magnitude is model-dependent, but is degenerate with effects from modes that were still sub-horizon at the end of inflation. In this scenario (but not necessarily in all scenarios), we conclude that the effect is not observable.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2026)·6 citations
26. 26*

    Neutron star cooling implications and magnetic field of the Vela Junior central compact object from all XMM-Newton and Chandra spectra

    Wynn C. G. Ho (Haverford)🇺🇸 · Esther Simkhayeva (Haverford)🇺🇸 · Alexander Y. Potekhin (Ioffe Institute)🇷🇺

    The central compact object (CCO) in the Vela Junior supernova remnant is a young neutron star whose relatively low X-ray flux and small distance suggest it has a mass high enough to activate fast neutrino cooling processes. Here we analyse all XMM-Newton MOS and pn and Chandra ACIS-S spectra of the Vela Junior CCO, with observations taking place over the 9 years from 2001 to 2010. We find that the best-fit flux and spectral model parameters do not vary significantly when treating each observation independently, and therefore we fit all the spectra simultaneously using various spectral models to characterize the predominantly thermal emission from the neutron star surface. Our results indicate the Vela Junior CCO has an atmosphere composed of hydrogen, a hot spot temperature (unredshifted) of 3.5x10^6 K, and a colder surface temperature of (6.6-8.8)x10^5 K. Possible absorption lines at ~0.6 keV and 0.9 keV provide evidence for the first-time of an average surface magnetic field B~3x10^10 G for this CCO, which is similar to the magnetic field of other CCOs. At the accurate new Vela Junior distance of 1.4 kpc, the observed luminosity that is dominated by the hot spot is ~5x10^32 erg s^-1. The luminosity from the rest of the colder surface is (1.3-4.0)x10^32 erg s^-1. The cool luminosity and temperature imply the Vela Junior CCO is indeed colder than many other young neutron stars and probably has a high mass that triggered fast neutrino cooling.

    ↳ astro-ph.HEastro-ph.SRhep-phnucl-thMNRAS(2026)·0 citations
27. 27*

    Entanglement scaling and dynamics in the Sauter-Schwinger effect

    S. Mahesh Chandran🇰🇷 · Karthik Rajeev🇬🇧

    In quantum field theory, entanglement entropy under spatial bipartitioning serves as a powerful information-theoretic probe of quantum correlations. In this work, we present the first comprehensive numerical study of the dynamical evolution and geometric scaling of entanglement entropy in a nonperturbative, strong-field QED setting -- specifically, in the context of the Sauter-Schwinger effect. While the weak-field regime is dominated by area-law states, we show that the entanglement entropy undergoes a transition from area-law to a volume-law scaling for certain strong-field regimes in the pulse-profile parameter space -- signaling a fundamental shift in the underlying correlation structure induced by nonperturbative pair production. For intermediate regimes, the scaling is a power-law that interpolates between area- and volume-law behavior. Finally, we provide interpretations based on the behavior of the low-energy pair-creation spectrum and discuss how these insights could inform future investigations of related phenomena.

    ↳ hep-thgr-qchep-phquant-ph1 citation

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.