The explicit form of the sixth order radiative corrections to the lepton $L$ ($L=e$, $\mu$, and $\tau$) anomalous magnetic moment from QED Feynman diagrams with insertion of the fourth order polarization operators consisting of either two closed lepton loops or one lepton loop crossed by a photon line is discussed in detail. The approach is based on the consistent application of dispersion relations for vacuum polarization operators and the Mellin-Barnes transform for massive photon propagators. Explicit analytical expressions for corrections to the lepton anomaly are obtained for the first time in the whole interval $0<r<\infty$ of the ratio $r$ of lepton masses $m_{\ell }/m_L$. Asymptotic expansions in the limit of both small $r\ll 1$ and large $r\gg 1$ computed from the exact expressions are found to be in perfect agreement with the ones earlier reported in the literature. We argue that in the region where the physical lepton mass ratios are located, the asymptotic expansions hold with an accuracy higher than the experimentally measured anomalies. The two loop diagrams with all three leptons different from each other are computed numerically and compared with the corresponding corrections from the pure two-bubble and one-bubble mixed diagrams. It is shown that there are regions of ratios $r$ where all three types of the fourth order polarization operator contribute equally to the anomaly.

We study the anisotropic Bianchi I and Bianchi II models in vacuum in the framework of deformed commutation relations. Working in a parametrization of the spatial metric by a volume and two anisotropy variables, we propose modified Poisson brackets that for the volume alone reproduce the bounce dynamics of effective loop quantum cosmology, with additional modifications for anisotropy degrees of freedom. We derive effective Friedmann equations and observe cosmological bounces in both Bianchi I and Bianchi II. For Bianchi II, we find that the cosmological bounce now interacts with the usual reflection seen in the Kasner indices in various interesting ways, in close similarity again with what had been seen in loop quantum cosmology. This suggests that the deformed commutation relation framework could model more general quantum-gravity-inspired bounce scenarios in a relatively straightforward way.

The vacuum Einstein equations admit a formulation closely analogous to the source-free Maxwell theory. In particular, the linearized equations exhibit an electric-magnetic duality symmetry. We develop a framework that makes this analogy manifest by explicitly identifying the electric and magnetic components of perturbative gravitational waves. Within this formulation, we show that duality rotations between these gravitoelectric and gravitomagnetic fields constitute a Noether symmetry of the linearized theory, and we derive the associated conserved current. The corresponding conserved charge encodes the difference in intensity between the right- and left-handed circularly polarized components of the gravitational wave—that is, between its self-dual and antiself-dual parts. Remarkably, this conservation law remains valid even when the gravitational perturbations propagate on generic curved backgrounds. We then investigate whether this symmetry survives quantization. While the duality symmetry is preserved at the quantum level in flat spacetime, we find that it is anomalously broken in curved backgrounds. As a result, an imbalance between right- and left-handed gravitons could be excited from the vacuum. This effect represents a chiral anomaly for massless spin-two fields, generalizing known results for fermions and spin-one photon fields.

In this paper, we study chiral non-Abelian domain walls in a phase of unconventional vacua of the Ginzburg-Landau model for dense QCD by considering a wider range of parameters space not directly deduced from QCD. The phase is characterized by asymmetric vacuum expectation values (VEVs), for example with the left scalar field, corresponding to the left quark-quark condensate, having a nonvanishing VEV and the right field having a vanishing one. The domain wall soliton interpolates between this vacuum and another where the left and right scalar fields switch roles. We study this formal possibility, but not any mechanism to generate these vacua nonperturbatively at finite density or finite temperature. Using a strong-coupling, or sigma-model limit, we are able to reduce the full dynamical complex matrix valued equations of motion to the sine-Gordon, a generalization of the sine-Gordon, and a generalization of the double sine-Gordon equations. In this limit, we prove nonexistence of domain walls in one of the vacua studied here, and we find full numerical computations to converge to the sigma-model limit for many cases, with some exceptions that we discuss.

We study the two-particle approximation of the Ising field theory (IFT), formulated in terms of the Bethe-Salpeter (BS) equation. Derived by Fonseca and Zamolodchikov as a systematic realization of the McCoy-Wu approach, this equation captures confinement by modeling “mesons” as bound states of two Majorana fermions (“quarks”), in a way analogous to the integral equation in the ’t Hooft model. Despite its approximate nature, the BS equation provides remarkably accurate predictions for the mass spectrum of stable mesons across a wide range of parameters. Motivated by the striking structural similarity between the BS equation in IFT and the ’t Hooft equation in two-dimensional QCD, we develop a new nonperturbative analytical framework inspired by the method of Fateev, Lukyanov, and Zamolodchikov. Within this approach, we compute spectral sums and systematically derive the large-$n$ expansion for the Bethe-Salpeter equation, which governs the spectrum of an infinite tower of mesons. We further examine how our analytical results capture the known behavior of the spectrum in well-studied asymptotic regimes, such as the $E_8$ limit and the free-fermion point, where exact solutions are available for comparison. Finally, we discuss how the obtained spectral data admit a natural analytic continuation to complex values of the parameters—an extension that was one of the primary motivations for this work.

The Stewart-Tolman effect posits that accelerating conductors exhibit both charge separation and rest-frame electric fields (“inertia of charge”), while the Ehrenfest-Tolman effect states that acceleration induces temperature gradients (“inertia of heat”). We study the interplay of these effects in thermodynamic equilibrium. Specifically, we derive from first principles a partial differential equation governing the electrothermal stratification of a fully ionized plasma in equilibrium under irrotational relativistic accelerations in curved spacetime. We then solve it in two settings: a plasma enclosed in a uniformly accelerated box, and a plasma shell suspended above a black hole horizon. The resulting electric fields are found not to depend on the electric conductivity of the medium.

We investigate the extraction of energy from a Kerr black hole via Alfvén waves (i.e., Alfvénic superradiance) in a force-free magnetosphere, in which the plasma inertia effects are ignored. We analyze the Poynting flux generated by Alfvén waves that propagate toward the event horizon across the inner light surface, the causal boundary for the waves. We find the relationship between the energy flux associated with Alfvén waves and that of the Blandford-Znajek (BZ) process. That is, both mechanisms can be described within a unified formulation of the Poynting flux, where the BZ process can be regarded as the long wavelength limit of the Alfvénic superradiance, and depending on the wave’s frequency, Alfvén waves enhance or suppress the Poynting flux in the BZ process. This unified framework for the BZ process and the Alfvénic superradiance would offer a valuable perspective for understanding the energy sources of high-energy astrophysical phenomena, such as relativistic jets.

We derive the response, the real part of which provides the tidal Love numbers, for nonextremal as well as extremal Kerr black holes under generic tidal perturbations. Our results suggest that the static as well as dynamical (linear-in-frequency) Love numbers vanish for both Schwarzschild and slowly rotating (linear-in-angular momentum) Kerr black holes, under generic perturbations. The vanishing of static and dynamical Love numbers also holds for axisymmetric tidal perturbations of nonextremal and extremal Kerr black holes. In fact, even under generic tidal perturbations, the static Love numbers of Kerr black holes vanish identically. The only case with nonzero Love numbers corresponds to the nonaxisymmetric dynamical tidal perturbations of Kerr black holes (to arbitrary order of angular momentum). We also demonstrate that the nonzero dynamical Love numbers, for both nonextremal and extremal Kerr black holes, get modified under the change of the sign of the spin weight, for electromagnetic and gravitational tidal perturbations.

While the third LIGO-Virgo gravitational-wave transient catalog includes 90 signals, it is believed that $\mathcal{O}({10}^5)$ binary black holes merge somewhere in the Universe every year. Although these signals are too weak to be detected individually with current observatories, they combine to create a stochastic background, which is potentially detectable in the near future. LIGO-Virgo searches for the gravitational-wave background using cross-correlation have so far yielded upper limits. However, Smith and Thrane [Phys. Rev. X 8, 021019 (2018).] showed that a vastly more sensitive, template-based search can be carried out by incorporating information about the phase evolution of binary black hole signals. This improved sensitivity comes at a cost; the template-based search is computationally expensive and requires a far more detailed understanding of systematic errors than is required for the cross-correlation search. In this work, we demonstrate the template-based approach with realistic data, paving the way for a gravitational-wave background search with unprecedented sensitivity.

In the current galaxy formation paradigm, collisions play a crucial role. A fraction of galaxy collisions results in fly-by events, and a galaxy that has passed through another galaxy is called a backsplash galaxy. Such fly-by events are of particular interest for explaining the quenching of isolated galaxies. One signature of backsplash galaxies is that they have high velocities relative to their environment, since they do not move in the same flow as surrounding galaxies. This feature can be studied in simulations, but it is also useful to have a theory that can predict the velocities of backsplash galaxies. In this paper, we develop such a theory based on the Zel’dovich approximation and use it to determine the maximal expected velocity of a backsplash galaxy in a given volume.

In this work we provide a detailed derivation of the observed galaxy number overdensity obtained by computing cosmological perturbations up to third order in redshift space and on very large scales. We compute all the relativistic and projection effects, arising from the observation of galaxies on the past light cone, including all redshift effects, i.e., peculiar velocities, Sachs-Wolfe (SW) effects, integrated SW effects, gravitational lensing, and time delay terms. Moreover, we have considered all post- and post-post-Born contributions from the photon geodesic equations in order to take into account all possible effects due to the lensing distortions. The derivation is performed in the Poisson gauge. This work largely follows the formalism used in Bertacca et al. pushing it for the first time up to the third perturbative order. This result will be important for a variety of applications, such as a complete estimation of projection effects and the investigation of possible parity violation signatures in the 3- and 4-point galaxy correlation functions.

We present a tool to compute the sensitivity of the Future Circular Electron-Positron Collider (FCC-ee) to the interactions of new, heavy particles via publicly available extensions to the smelli and flavio computer programs. We parametrize new particles’ effects without any flavor assumptions and take into account the projected experimental and correlated theoretical uncertainties of various electroweak and Higgs observables at the proposed collider. We illustrate a use of the tool by estimating the sensitivity of the FCC-ee to a $Z^{\prime }$ model with flavor-specific couplings, which explains anomalies inferred from present-day measurements and Standard Model predictions of observables that involve the $b\to s{\ell }^{+}{\ell }^{-}$ transition.

Recently, it was observed that an aggressive cut on the $b$ jets’ transverse momenta applied to Higgs boson production in weak-boson fusion followed by the decay $H\to b\overline{b}$ leads to very large QCD corrections to the fiducial cross section. In this paper, we show that these corrections are caused by soft and collinear QCD radiation and, therefore, can be efficiently treated by a parton shower. We combine the parton-shower description of the decay $H\to b\overline{b}$ with next-to-next-to-leading order QCD corrections to Higgs production in weak-boson fusion and its subsequent decay and demonstrate that the quality of the theoretical prediction is markedly improved even if $b$ jets with rather high transverse momenta are selected. The remaining uncertainty of the theoretical prediction, mainly driven by imprecise modeling of $H\to b\overline{b}$ decay, is estimated to be of the order of $\mathcal{O}(5–7\%)$.

We investigate the nucleon’s chiral-odd generalized parton distribution functions (GPDs) in the large-$N_c$ limit of quantum chromodynamics (QCD). Extending previous work [Phys. Rev. D 111, 074007 (2025)] on the leading-order contribution in the $1/N_c$ expansion, we focus on the next-to-leading-order contributions and provide a complete set of flavor-singlet and flavor-non-singlet chiral-odd GPDs. This study includes the derivation of the spin-flavor structure of the baryon matrix element of the chiral-odd operator, the proof of the polynomiality property and associated sum rules, and numerical estimates based on the gradient expansion. The spin-flavor structure of the nucleon matrix element is interpreted through a multipole expansion in the transverse momentum transfer, leading to the definition of multipole mean-field GPDs. Using these GPDs as the basis of our analysis, we take their $m$th moments and demonstrate the polynomiality property within the mean-field framework, making use of discrete symmetries in the proof. In particular, the first moments ($m=1$) of the GPDs are related to the nucleon tensor form factors, as generally required. By performing a gradient expansion, we compute the chiral-odd GPDs and present numerical estimates. Our results show reasonable agreement with lattice QCD predictions.

Pion condensation in ultrarelativistic collisions presents a compelling theoretical phenomenon with significant implications for the dynamics of hadronic matter. Various theoretical frameworks offer insight into the nature of high-temperature Bose-Einstein condensation (BEC). The present study investigates the dissipative behavior of a relativistic pion gas undergoing BEC in ultrarelativistic heavy-ion collisions. Further, we obtain viscosity ($\eta$), bulk viscosity ($\zeta$), and speed of sound ($c_s$) by employing the Boltzmann transport equation with the relaxation time approximation. Findings show a substantial drop in $\eta /s$ and $\zeta /s$ with the fractional increase in condensation. This effect is becoming more evident in larger systems approaching the thermodynamic limit. Alongside the reduction in viscosities, the speed of sound also decreases with increasing condensation, indicating a softening of the equation of state. The analysis of finite-size effects reveals that larger systems exhibit more pronounced signatures of BEC. These results suggest that pion condensation can influence the hydrodynamic evolution of the hadronic phase in heavy-ion collisions, with consequential implications for interpreting collective flow observables and the underlying equation of state.

Fast and accurate muon reconstruction is crucial for neutrino telescopes to improve experimental sensitivity and enable online triggering. This paper introduces a hybrid-graph neural network (GNN) method tailored for efficient muon track reconstruction, leveraging the robustness of GNNs, alongside traditional physics-based approaches. The “light GNN model” achieves a run-time of 0.19–0.29 ms per event on GPUs, offering a 3 orders of magnitude speedup compared to traditional likelihood-based methods, while maintaining a high reconstruction accuracy. For high-energy muons (10–100 TeV), the median angular error is approximately 0.1°, with errors in reconstructed Cherenkov photon emission positions being below 3–5 m, depending on the GNN model used. Furthermore, the semi-GNN method offers a mechanism to assess the quality of event reconstruction, enabling the identification and exclusion of poorly reconstructed events. These results establish the GNN-based approach as a promising solution for next-generation neutrino telescope data reconstruction.

We study the holographic description for general stress-energy tensor deformations in arbitrary dimensions using the metric flow approach. Mixed boundary conditions corresponding to these deformations emerge from solutions to the metric flow equations. To test this proposal, we analyze planar anti-de Sitter black holes with such boundary conditions and find that the deformed energies satisfy flow equations consistent with the field theory interpretation. We further derive the commuting condition for stress-energy tensor deformations and extend the mixed boundary condition description to accommodate families of commuting deformations.

We introduce a general approach to realize quantum states with holographic entanglement structure via monitored dynamics. Starting from random unitary circuits in $1+1$ dimensions, we introduce measurements with a spatiotemporally modulated density. Exploiting the known critical properties of the measurement-induced entanglement transition, this allows us to engineer arbitrary geometries for the bulk space (with a fixed topology). These geometries in turn control the entanglement structure of the boundary (output) state. We demonstrate our approach by giving concrete protocols for two geometries of interest in two dimensions: the hyperbolic half-plane and a spatial section of the Bañados-Teitelboim-Zanelli black hole. We numerically verify signatures of the underlying entanglement geometry, including a direct imaging of entanglement wedges by using locally entangled reference qubits. Our results provide a concrete platform for realizing geometric entanglement structures on near-term quantum simulators.

The weak gravity conjecture can be formulated as a statement that gravity must be the weakest force, compared to the other interactions in low-energy effective field theory (EFT). Several arguments in favor of this statement were presented from the side of string theory and black hole physics. However, it is still an open question whether the statement of weak gravity can be proven based on more general assumptions of causality, unitarity, and locality of the fundamental theory. These consistency requirements imply the dispersion relations for the scattering amplitudes, which allow us to bound the EFT coefficients. The main difficulty for obtaining these constraints in the presence of gravity is related to the graviton pole, which makes the required dispersion relations divergent in the forward limit. In this work, we present a new way of deriving the bound on the ratio between the EFT cutoff scale and Planck mass from confronting the IR divergences from the graviton pole and one-loop running of the EFT Wilson coefficient in front of the dimension-12 operator. Our method also allows the incorporation of full unitarity of the partial wave expansion of the UV theory. We examine the EFT of a single shift-symmetric scalar in four dimensions and find that the relation between the EFT coupling in front of the dimension-12 operator and the Planck mass.

Analog Hawking radiation emitted by a perfectly reflecting mirror in ($1+3$)-dimensional flat spacetime is investigated. This is accomplished by studying the reflected frequency and momentum based on Einstein’s mirror, instead of the canonical way of solving, if possible, wave equations subjected to a dynamical Dirichlet boundary condition. In the case of a finite-size mirror, diffraction pattern appears in the radiation spectrum. Based on the relevant parameters in the proposed analog black hole evaporation via lasers experiment, in which the Hawking temperature $T_H\simeq 0.03\mathrm{eV}$ and the mirror area $\mathcal{A}\simeq (50\mathrm{\mu }\mathrm{m}{)}^2$, the Hawking photon yield is estimated to be $N\simeq 16/\mathrm{laser}$ shot.