Direct detections of gravitational waves offer a unique opportunity to test gravity in the highly dynamical and strong field regime. Current tests are typically performed assuming signals from quasicircular binaries. However, the complex waveform morphology induced by orbital eccentricity can enhance our ability to probe gravity with greater precision. A recent analysis of the neutron star–black hole event GW200105 identified strong evidence for orbital eccentricity. We extend an eccentric-precessing waveform model to test alternative models with this signal by incorporating eccentric corrections induced by Brans-Dicke, Einstein-dilaton-Gauss-Bonnet, and dynamical Chern-Simons gravity at leading post-Newtonian order. We show that analyzing this event with a quasicircular model leads to a false deviation from general relativity, while the inclusion of eccentricity improves the bounds on the models. Our analysis of GW200105 places tight constraints on Einstein-dilaton-Gauss-Bonnet gravity, ${\alpha }_{\mathrm{EdGB}}^{1/2}\lesssim 2.38\mathrm{km}$, and Brans-Dicke gravity, ${\omega }_{\mathrm{BD}}\gtrsim 3.5$, while dynamical Chern-Simons gravity remains unconstrained due to the low spin content.

Fermions are coupled to the Einstein-Cartan system in the canonical formulation, including the cosmological, the Barbero-Immirzi, and the nonminimal coupling constants. The resulting ten first-class constraints generate gauge transformations that are on-shell equivalent to spacetime diffeomorphisms and $\mathrm{SL}(2,\mathbb{C})$ transformations. The gravitational second-class constraints receive fermionic contributions, which can be implemented by use of Dirac brackets or by solving them directly. Furthermore, we identify new fermionic (second-class) constraints that are necessary to recover the Dirac-fermion theory by relating the momenta to the configuration variables on dynamical solutions; this fermionic phase-space reduction is accomplished by use of corresponding Dirac brackets. The theory remains well defined off the Dirac-Fermion constraint surface with four additional degrees of freedom. Discrete ($CPT$) symmetries as well as implications for canonical quantization and modified theories of gravity with fermions are discussed.

Mass estimates of white dwarfs via electromagnetic methods, often differ from those obtained through gravitational redshift measurements, in some cases with discrepancies ranging in 5%–15% across independent datasets. Although many of the discrepancies reported in large spectroscopic surveys and confirmed by high-precision techniques such as astrometric microlensing and wide-binary analyses may be attributable to thermal effects, model uncertainties or measurement errors prevent a complete description of some of the observations. Here, we explore an alternative explanation based on the presence of a gravitationally coupled bosonic scalar field that contributes to the stellar mass while remaining electromagnetically invisible. We construct stationary, static mixed configurations consisting of a white dwarf that presents a bosonic scalar field (dark matter) component, forming a composite white dwarf–boson star system. We explore families of solutions showing that a scalar field fraction of $f_{\mathrm{DM}}\sim 5\%–15\%$ to the mass contribution can account for the observed redshift excess. Our models provide a physically motivated explanation for the mass bias, might offer new observational signatures, and allow us to place preliminary constraints on the mass and compactness of the scalar field configuration. Finally, using our theoretical framework in combination with Bayesian model selection we provide plausible bounds for the mass of the constituent (ultralight) bosonic particle.

Astrophysical jets from powerful active galactic nuclei (AGN) have recently been proposed as promising probes of dark matter (DM) in the sub-GeV mass range. AGN launch relativistic jets that accelerate cosmic rays (CRs) to very high energies, which can then interact with their surroundings and produce multiwavelength (MW) emission spanning from radio frequencies to TeV $\gamma$ rays. If DM consists of light particles, their interactions with CRs could lead to an additional cooling mechanism that modifies the expected MW emission. In this work, we analyze the MW spectrum of Markarian 421, a well-studied AGN, using a multizone leptonic jet model that includes the interactions between CR electrons and DM particles. For the first time, we account for the uncertainties in the astrophysical jet dynamics, which have been previously neglected when constraining the CR-DM interactions. By fitting simultaneously jet parameters and DM-electrons interactions, we use the MW data from Markarian 421 to set constraints on the DM-induced CR cooling. We obtain $5\sigma$ upper limit ${\sigma }_{\mathrm{DM}-\mathrm{e}}\lesssim 1\times {10}^{-34}{\mathrm{cm}}^2$ for a DM mass of 1 MeV. We demonstrate that this is about a factor of 2–10 stronger than traditional approaches depending on DM mass. This improvement originates from having indeed considered the full multiwavelength emission from the source, instead if a simplified approach. Properly accounting for degeneracies between jet dynamics and DM interactions is also key to deriving robust constraints on DM interactions.

In a recent paper, “Nonlocal nucleon matrix elements in the rest frame” [1], it was observed that the next-to-leading order calculations of the renormalization factor can describe, to a few percent accuracy, the logarithm of the lattice quantum chromodynamics (QCD) rest frame matrix elements with separations up to distances of 0.6 fm on multiple lattice spacings. We argue that perturbative QCD breaks down at such a distance scale after resumming the associated large logarithms, while the Ansatz used in the analysis there is not justified in perturbation theory. Besides, we explain the observation in Ref. [1] and demonstrate that the Ansatz fails to describe the data for $z>0.3\mathrm{fm}$, showing an opposite trend. Finally, although Ref. [1] proposes multiplying the Ansatz by a Gaussian correction model, which is shown to reduce the discrepancy with the data, this does not legitimize the use of perturbative QCD at such distance scales.

Solving interacting field theories at finite densities remains a numerically and conceptually challenging task, even with modern computational capabilities. In this paper, we propose a novel approach based on an expansion of the Euclidean path integrals using radial basis function neural networks, which allows the calculation of observables at finite densities and overcomes the sign problem in a numerically very efficient manner. The method is applied to an interacting complex scalar field theory at finite chemical potential in $3+1$ dimensions, which exhibits both the sign problem and the silver blaze phenomenon, similar to QCD. The critical chemical potential at which phase transition occurs is estimated to be ${\mu }_c=1.17\pm 0.018$, and the silver blaze problem is accurately described below ${\mu }_c$.

We analyze identified hadron spectra in pp collisions at $\sqrt{s}=13\mathrm{TeV}$ measured by ALICE within a nonextensive statistical framework. Spectra classified by multiplicity, flattenicity, and spherocity were fitted with the Tsallis-Pareto distribution, and the parameters were studied on the Tsallis thermometer. Multiplicity and flattenicity classes follow a previously observed scaling, while the nonextensivity parameter shows a distinct sensitivity to the spherocity. A data-driven parametrization confirms a proportionality between the Tsallis temperature and mean transverse momentum, offering a simple estimate of the effective temperature. These results highlight the ability of the Tsallis thermometer to capture both multiplicity and event-shape effects, linking soft and hard processes in small systems.

We accurately compute the renormalization group (RG) exponents $Y_q$ of large $q$ fields at the $O(2)$ invariant fixed point in three dimensions. We build on an iterative approach that has been previously proposed and is implemented by using the worm algorithm. We simulate an improved XY model, that has next-to-next-to-nearest couplings in addition to nearest ones. In the worm update we incorporate weights, which allows us to obtain accurate results up to $q=64$. For example we get $Y_q=1.76370(12)$, 0.89167(23), and $-0.11203(34)$ for $q=2$, 3, and 4, respectively. The comparison with the large $q$ effective field theory gives an excellent agreement down to $q=4$ and provides accurate estimates of the parameters of the effective field theory.

Motivated by the recently obtained Hadrons to Atomic nuclei from Lattice QCD potentials for the $N\text{−}\varphi$, $N\text{−}J/\psi$, and $N\text{−}{\eta }_c$ interactions, we investigate the structure of the exotic nuclei ${}_{\varphi }{}^8\mathrm{Be}$, ${}_{J/\psi }{}^8\mathrm{Be}$, and ${}_{{\eta }_c}{}^8\mathrm{Be}$ as $\alpha +\alpha +M$ three-body systems ($M$ denotes the meson). The bound and resonant states are calculated consistently using the Gaussian expansion method, with resonances identified via the complex scaling method. For the $\alpha \varphi$ and $\alpha$-charmonium interactions, a folding potential is constructed based on the Hadrons to Atomic nuclei from Lattice (HAL) QCD potentials and fitted to a Woods-Saxon form. We find that the $\varphi$ meson exhibits a strong “gluelike” effect, binding the $0_1^{+}$, $2_1^{+}$, and $4_1^{+}$ resonant states of ${}^8\mathrm{Be}$ into stable states and significantly reducing the $\alpha \text{−}\alpha$ distance. In contrast, the interactions of $J/\psi$ and ${\eta }_c$ with the nucleus are weaker, forming only shallow bound states with the $0_1^{+}$ state of ${}^8\mathrm{Be}$ and even increasing the $\alpha \text{−}\alpha$ separation. Notably, our analysis predicts weakly bound $\alpha \text{−}J/\psi$ states in the ${{}^{4}S}_{3/2}$ and ${{}^{2}S}_{1/2}$ channels, a result not reported in prior studies, which suggests that ${}_{J/\psi }{}^8\mathrm{Be}$ may not be a Borromean nucleus. The sensitivity of the ${}_{\varphi }{}^8\mathrm{Be}(4_1^{+})$ state—transitioning from bound to resonant depending on the $\alpha$-particle radius—highlights the subtle dynamics at play. These results provide a systematic theoretical comparison of how different vector mesons modify nuclear clustering, offering critical predictions for future experimental searches of such exotic hadron-nucleus systems.

The BESIII Collaboration has recently observed a resonant structure $Y(4500)$ in $e^{+}{e}^{-}\to J/\psi K^{+}{K}^{-}$, whose origin remains unresolved. In this study, we analyze the cross section line shape of $e^{+}{e}^{-}\to J/\psi K^{+}{K}^{-}$ by taking into account the $\psi (4415)$ state and intermediate charmed meson loops. By treating $\psi (4415)$ as both a pure $S$-wave state and $S-D$ mixed states, and introducing the $Z_{cs}^{(\prime )}$ resonance, we find that the $Y(4500)$ peak at $\sqrt{s}=4.5\mathrm{GeV}$ arises from the triangle singularity mechanism in the $Z_{cs}^{(\prime )}$-mediated rescattering processes, supporting its interpretation as a threshold effect rather than a conventional resonance.

We present a systematic comparison of charmonium light-front wave functions obtained through two complementary nonperturbative approaches: basis light-front quantization (BLFQ) and Dyson-Schwinger equations (DSEs). Key observables include the charge form factor, gravitational form factors, light-cone distribution amplitudes, decay constants, and two-photon transition form factors. Despite their distinct theoretical foundations and model parameters, the predictions from BLFQ and DSEs exhibit remarkable agreement across all observables. This convergence validates both frameworks for studying charmonium structure and highlights the complementary strengths of Hamiltonian-based (BLFQ) and Lagrangian-based (DSEs) methods in addressing nonperturbative QCD.

Event reconstruction at the LHC, the task of assigning observed physics objects to their true origins, is a central challenge for precision measurements and searches. Many existing machine learning approaches address this problem but rely on a single event topology, restricting their applicability to realistic analyses where multiple signal and background processes with different structures are present. To overcome this, we present TIGER, a novel hierarchical graph network that is fundamentally topology agnostic. By incorporating only the common underlying structure of sequential two-body decays, our model can reconstruct complex events without process-specific assumptions. This flexible architecture supports multitask learning, enabling simultaneous event reconstruction and classification. TIGER thus provides a powerful and generalizable tool for physics analysis at the LHC.

Affleck-Dine baryogenesis is compelling yet challenging to probe because of the high-energy physics involved. We demonstrate that this mechanism can be generically realized with low-energy new physics without supersymmetry while producing detectable gravitational waves (GWs) sourced by parametric resonance of a light scalar field. In viable models, the scalar has a mass of $\mathcal{O}(0.1–10)\mathrm{GeV}$, yielding GWs with peak frequencies of $\mathcal{O}(10–100)\mathrm{Hz}$. This study further reveals a new complementarity between upcoming LIGO-frequency GW detectors and laboratory searches across frontiers of particle physics.

In this paper we take the initial steps toward a formulation of species quantum mechanics. Specifically, we consider quantum operators that correspond to the species number $N_s$ and the tower mass scale $m_t$ in the context of the swampland distance conjecture. We discuss the commutation relations, a possible wave function, and symplectic duality transformations on the conjugate variables. Furthermore, we argue that the Castellano-Ruiz-Valenzuela (CRV) pattern is a consequence of the canonical commutation rules of moduli space quantum mechanics. We also connect the canonical quantization to the periods of $\mathcal{N}=2$ Calabi-Yau compactifications to explore other aspects of the CRV pattern, including its possible connection to the Ooguri-Vafa-Verlinde black hole quantization procedure.

Effective models of gravitational collapse inspired by loop quantum gravity typically resolve the central singularity by replacing it with a bounce of the matter density in the Planckian regime. In the specific model analyzed here, this bounce is generally followed by the formation of shell-crossing singularities. The purpose of this work is to provide a physically meaningful extension of spacetime beyond the shell-crossing singularity. To this end, we derive the dynamics of a dust thin shell within the effective Hamiltonian framework. The motion of the shell remains timelike throughout: after undergoing a quantum-gravitational bounce, it expands and eventually emerges from the white hole vacuum region.

We derive a system of differential equations which are satisfied by the vacuum expectation values (vevs) of BPS Wilson loops and ’t Hooft coupling of ABJM theory. They are Picard-Fuchs equations of an algebraic curve defined by the derivative of the planar resolvent of the corresponding matrix model. The weak and strong coupling behaviors can be reproduced by their local solutions around regular singularities. We also obtain a recursion relation which can be used to determine the planar vevs of BPS Wilson loops in arbitrary representations.

We construct the energy-momentum tensor of the $\mathrm{O}(N)$ linear sigma model explicitly in the large $N$ limit using the exact renormalization group (ERG) formalism. The energy-momentum tensor is obtained as a cutoff dependent functional of $N$ scalar field variables. Our guiding principles behind the construction are twofold: first the energy-momentum tensor must satisfy the Ward identity for translation and rotation invariance, and second the energy-momentum tensor must satisfy a variant of the exact renormalization group equation. In the limit that the momentum cutoff goes to zero, our energy-momentum tensor gives the one-particle irreducible (1PI) effective action with the insertion of a single energy-momentum tensor operator. We verify that the energy-momentum tensor constructed satisfies the expected trace formula, and that the trace vanishes at the Wilson-Fisher critical point.

Arm-locking frequency stabilization is a key technique for suppressing laser frequency noise in space-based gravitational-wave detectors. The robustness of the arm-locking control loop is crucial for maintaining laser frequency stability, which directly impacts the accuracy of gravitational-wave measurements. In this work, a parametric stability analysis framework is developed by combining the D-subdivision theory with the Semi-Discretization method to map the stability regions of arm-locking systems in the parameter space and to identify their critical stability boundaries. Based on the frequency-domain characteristics, a robust arm-locking controller is designed to enhance loop stability under parameter perturbations. Theoretical analysis and time-domain simulations confirm that the proposed controller maintains closed-loop stability and realizes suppression of laser frequency noise against parameter perturbation.

We numerically study the approach to the singularity in ${\mathbb{T}}^2$-symmetric cosmological spacetimes containing a nonstiff perfect fluid satisfying a linear equation of state $p=K\rho$, $K\in [0,1)$. Near the singularity, the dynamics are found to be local and oscillatory. In particular, our results show, for the first time, that the fluid velocity in inhomogeneous cosmologies develops mixmaster-esque oscillations consistent with the generalized Belinskiĭ, Khalatnikov, and Lifschitz conjecture of Uggla et al. Moreover, we find these fluid oscillations are responsible for the development of local inhomogeneities in the matter density of the early Universe.