In this paper we construct the first phenomenological waveform model, which contains the “complete” $\ell =2$ spherical harmonic mode content for gravitational wave signals emitted by the coalescence of binary black holes with spin precession: The model contains the dominant part of the gravitational wave displacement memory, which manifests in the $(\ell =2,m=0)$ spherical harmonic in a co-precessing frame, as well as the oscillatory component of this mode. The model is constructed by twisting up the oscillatory contribution of the mode, as it was previously done for the rest of spherical harmonic modes in IMRPhenomTPHM and the Phenom family of waveform models. Regarding the displacement memory contribution present in the aligned spin (2,0) mode, we discuss a procedure to analytically compute the “precessing memory” in all the $\ell =2$ modes using the integration derived from the Bondi-Metzner-Sachs balance laws. The final waveform of the (2,0) mode is then obtained by summing together both contributions. We implement this as an extension of the computationally efficient IMRPhenomTPHM waveform model, and we test its accuracy by comparing against a set of numerical relativity simulations. Finally, we employ the model to perform a Bayesian parameter estimation injection analysis.

A popular approach to constructing exact stationary and axisymmetric nonvacuum solutions in general relativity has been to use solution-generating techniques. Here we revisit a recent variant of the Newman-Janis-Azreg-Aïnou algorithm—restricted to asymptotically flat spacetimes—and demonstrate that this method exclusively generates Konoplya-Stuchlík-Zhidenko spacetimes. Therefore, the equations for geodesic motion and scalar-wave propagation are both separable. We call these “doubly separable” spacetimes. Of these, we identify a “degenerate” subclass that might admit a separable Dirac equation by explicitly obtaining the Killing-Yano tensor. While the degenerate subclass is Petrov type D, the general doubly separable spacetimes are of type I. The high degree of symmetry in these spacetimes suggests that the self-gravitating matter must also be in specialized field configurations. For this reason, we investigate whether these spacetimes can even be sourced by arbitrary types of matter. We show that doubly separable spacetimes cannot be sourced by massless real scalar fields or perfect fluids, and that electromagnetic fields lead only to the Kerr-Newman family. Notably, this rules out the correct spinning counterpart of the Janis-Newman-Winicour naked singularity spacetime, which contains a scalar field, as a member of this metric class. While the algorithm generates spacetimes with rich symmetry structures, valuable for studying phenomena like black hole shadows and quasinormal modes, our results highlight the need for caution when using it to construct physically consistent solutions with prespecified matter content.

We investigate radiative recombination under conditions where both electrons and protons are in motion, thereby avoiding the stationary-ion approximation. The recombination cross section and rate coefficient are evaluated as functions of the kinematic parameters, with emphasis on regimes characteristic of the solar atmosphere, solar wind, and heliosphere. Particular attention is given to the impact of proton motion on the recombination rate. The total cross section is evaluated within the framework of nonrelativistic quantum electrodynamics, appropriate for particle energies typical of the solar atmosphere and solar wind. The results demonstrate that accounting for proton motion enhances the overall recombination rate.

The energy spectra of cosmic rays (CRs) below tens of GeV are significantly modulated by solar activity within the heliosphere. To investigate the properties of Galactic CRs, it is important to determine the unmodulated local interstellar spectrum (LIS). Recent high-precision temporal measurements of CR energy spectra, released by the AMS-02 Collaboration, provide a crucial observational foundation for this endeavor. In this study, we employ the widely used force-field approximation (FFA) model to analyze the AMS-02 data and attempt to derive the LIS for CR protons and positrons. By applying a non-LIS method, we derive temporal variations of the relative solar modulation potential, $\mathrm{\Delta }\varphi$, for individual particle species. Our analysis demonstrates that the FFA provides sufficient accuracy in explaining the AMS-02 spectral measurements of all particles during the low solar activity period. Notably, the derived $\mathrm{\Delta }\varphi (t)$ for protons and positrons, as well as for electrons and antiprotons, exhibits excellent consistency, indicating that particles with the same charge sign can be effectively described within a unified FFA framework during the low solar activity period. Having established a well-constrained proton LIS and its associated modulation potential, we apply the common modulation behavior between positrons and protons to demodulate the AMS-02 positron measurements and derive the positron LIS without necessitating prior knowledge of its characteristics. This LIS is meaningful for quantitative investigations into potential exotic origins of CR positrons.

We investigate the thermal properties of hadrons in two-color quantum chromodynamics (${\mathrm{QC}}_2\mathrm{D}$) using the functional renormalization group method, with particular focus on modifications of the $U(1)$ axial anomaly effects. The hadrons are described by a linear sigma model based on the Pauli-Gürsey $SU(4)$ symmetry, which incorporates both low-lying $0^{\pm }$ mesons and diquark baryons. We find that all quartic couplings are comparably suppressed when physical values of the pion mass and decay constant are taken as inputs, for which a reasonably smooth chiral symmetry restoration at finite temperature is reproduced. Consequently, mass differences among chiral partners remain small. Despite these tiny mass differences, mass degeneracies of chiral partners in the hot medium are clearly demonstrated, consistent with chiral symmetry restoration. Moreover, we find that the couplings responsible for the $U(1)$ axial anomaly are enhanced upon entering the finite-temperature regime. Baryonic fluctuations also provide sizable contributions to these enhancements. Finally, the fate of the topological susceptibility in the hot ${\mathrm{QC}}_2\mathrm{D}$ medium is examined.

We investigate the T-odd nucleon energy correlator (NEC) at small-$x$ and establish its connection with the spin-dependent odderon. Probing the T-odd NEC involves measuring a single transverse spin asymmetry (SSA) for the energy pattern in the target fragmentation region in deep inelastic scattering. We find that while the inclusive energy pattern results in a vanishing SSA, a nonzero SSA emerges when restricting the measurement to charged hadrons, which are directly measured in tracking detectors. To describe this effect, we introduce the track-based NEC and evaluate its small-$x$ limit from fracture functions using the energy sum rule. The resulting SSA exhibits an opposite sign between positively and negatively charged hadrons, providing a clear experimental signature of the odderon. Furthermore, by incorporating charge weighting into the NEC, we construct a $C$-odd tag in the final state, eliminating potential contamination from $C$-even gluonic contributions. Our results demonstrate that these track-based energy-pattern observables offer a clean and sensitive probe for unveiling odderon dynamics at the future electron-ion collider.

We investigate the single-spin asymmetry for the single-inclusive production of hadrons and jets in collisions of transversely polarized nucleons and unpolarized leptons, $\ell N^{\uparrow }\to (h\mathrm{or}\text{jet})X$. We compute the spin-dependent cross section within collinear twist-3 factorization in perturbative QCD at next-to-leading order (NLO) accuracy. In this approach, multiparton correlations generate a nonvanishing effect. For the present paper, we focus on correlations in the nucleon initial-state rather than in the fragmentation process. We explicitly verify that collinear twist-3 factorization is valid at the one-loop level. Our analytical results show that at NLO the relevant multiparton correlation functions in the nucleon are probed on their full support in momentum fractions. Our numerical analysis for collisions at the Electron-Ion Collider indicates that the NLO corrections can be large and are sensitive to the functional form of the twist-3 correlation functions.

The correct description of the hadron’s structure requires understanding how quarks and gluons form the observable hadrons and how they are distributed within them. Two key nonperturbative quantities encapsulate this information: parton distribution functions (PDFs) and fragmentation functions (FFs). The former define a probabilistic light-front momentum distribution of partons within a hadron, whereas the latter describe the hadronization process of high-energy partons. Computing these functions analytically poses significant challenges, as it demands models that accurately incorporate the nonperturbative infrared dynamics of quantum chromodynamics (QCD). In this work, we compute the pion PDF and its elementary and full FFs using the Curci-Ferrari (CF) model. This model enables the exploration of nonperturbative QCD effects by introducing a gluon-mass scale within the Landau gauge QCD Lagrangian. The two-point quark and gluon correlation functions derived from the CF model agree well with lattice-QCD results and reproduce the pion decay constant in the chiral limit, consistent with chiral perturbation theory. The resulting pion PDF and FFs computed with the CF quark propagator and pion Bethe-Salpeter amplitude are in good qualitative and quantitative agreement with those obtained using the Qin-Chang model, a benchmark approach to nonperturbative QCD. These findings support the broader applicability of the Curci-Ferrari model in hadron phenomenology.

Beam dump experiments represent an effective way to probe new physics in a parameter space, where new particles have feeble couplings to the Standard Model sector and masses below the GeV scale. The LUXE experiment, designed primarily to study strong-field quantum electrodynamics, can be used also as a photon beam dump experiment with a unique reach for new spin-0 particles in the 10–350 MeV mass and ${10}^{-6}–{10}^{-3}{\mathrm{GeV}}^{-1}$ couplings to photons ranges. This is achieved via the “new physics search with optical dump” (NPOD) concept. While prior estimations were obtained with a simplified model of the experimental setup, in this work we present a systematic study of the new physics reach in the full, realistic experimental apparatus, including an existing detector to be used in the LUXE NPOD context. We furthermore investigate updated scenarios of LUXE’s experimental plan and confirm that our results are in agreement with the original estimations of a background-free operation.

By analyzing $(10087\pm 44)\times {10}^{6}J/\psi$ events collected with the BESIII detector at the BEPCII, the decays $J/\psi \to {\mathrm{\Xi }}^0\overline{\mathrm{\Lambda }}{K}_S^0+c.c.$, $J/\psi \to {\mathrm{\Xi }}^0{\overline{\mathrm{\Sigma }}}^0{K}_S^0+c.c.$, and $J/\psi \to {\mathrm{\Xi }}^0{\overline{\mathrm{\Sigma }}}^{-}{K}^{+}+c.c.$ are observed for the first time. Their branching fractions are determined to be $\mathcal{B}(J/\psi \to {\mathrm{\Xi }}^0\overline{\mathrm{\Lambda }}{K}_S^0+c.c.)=(3.76\pm 0.14\pm 0.23)\times {10}^{-5}$, $\mathcal{B}(J/\psi \to {\mathrm{\Xi }}^0{\overline{\mathrm{\Sigma }}}^0{K}_S^0+c.c.)=(2.24\pm 0.32\pm 0.31)\times {10}^{-5}$, and $\mathcal{B}(J/\psi \to {\mathrm{\Xi }}^0{\overline{\mathrm{\Sigma }}}^{-}{K}^{+}+c.c.)=(5.64\pm 0.17\pm 0.28)\times {10}^{-5}$, where the first uncertainties are statistical and the second systematic.

As in the gravitational context, one of the most challenging open questions in analogue black holes formed in Bose-Einstein condensates concerns the backreaction of Hawking-like radiation on the condensate and its subsequent evolution. In this work we derive the basic equations describing this backreaction within the density-phase formalism, which avoids infrared divergences and is particularly well suited to one-dimensional configurations.

Motivated by the duality between elasticity and fracton gauge theory, we study an extension of the gauge group that includes the quadrupole moment. Remarkably, we find that spontaneous breaking of the quadrupole symmetry increases the number of massless excitations. This result appears to challenge the well-established paradigm, according to which gauge fields acquire mass through the Higgs mechanism, and the would-be Goldstone bosons are rendered massive. We refer to this phenomenon as the anti-Higgs mechanism. Furthermore, we demonstrate that the quadrupole gauge theory is dual to an exotic class of elastic systems, which we dub incompressible crystals, and the anti-Higgs mechanism in the dual theory corresponds to a phase transition from the incompressible crystal state to an ordinary (compressible) solid.

We present the first unified model for the general relativistic dynamics and gravitational radiation of generic compact binaries. TEOBResumS-Dalí is a model based on the effective-one-body framework incorporating tidal interactions, generic spins, multipolar radiation reaction/waveform, and numerical relativity information. It allows the computation of gravitational waves and other dynamical gauge invariants from generic binaries (black holes, neutron stars, and neutron star–black hole binaries) evolving along arbitrary orbits (quasicircular, eccentric, and nonplanar) through merger and including scattering. The performances of TEOBResumS-Dalí in the strong-field regime are showcased by comparisons with a large sample of 1395 high-accuracy numerical relativity simulations. TEOBResumS-Dalí allows the computation of faithful waveforms for gravitational wave astronomy, providing at the same time an understanding and a prediction of the strong-field dynamics.

We investigate a higher-form symmetry in type IIB superstring theory, which possesses an $\mathrm{SL}(2,\mathbb{Z})$ symmetry. From the point of view of the low-energy effective field theory, the $\mathrm{SL}(2,\mathbb{Z})$ symmetry is treated as a gauge symmetry. Hence, an 8-form global symmetry ${\mathbb{Z}}_{12}^{[8]}$ emerges as a quantum symmetry. In this paper, we present an explicit construction of the topological operator associated with the ${\mathbb{Z}}_{12}^{[8]}$ symmetry. In this construction, the discriminant $\mathrm{\Delta }(\tau )$ plays a central role. As a result, it becomes manifest that ${\mathbb{Z}}_{12}^{[8]}$ is the solitonic symmetry of 7-branes. Furthermore, taking into account the extensions of the duality group, we also discuss what global symmetries emerge when considering not $\mathrm{SL}(2,\mathbb{Z})$ but $\mathrm{Mp}(2,\mathbb{Z})$, $\mathrm{GL}(2,\mathbb{Z})$, and ${\mathrm{Pin}}^{+}(\mathrm{GL}(2,\mathbb{Z}))={\mathrm{GL}}^{+}(2,\mathbb{Z})$.

Topological symmetry operators of holographic large $N$ ${\mathrm{CFT}}_D$’s are dual to dynamical branes in the gravity dual ${\mathrm{AdS}}_{D+1}$. We use this correspondence to establish a dictionary between thermal expectation values of symmetry operators in the Euclidean ${\mathrm{CFT}}_D$ and the evaluation of gravitational saddles in the presence of a dynamical brane. Expectation values of 0-form symmetry operators in the ${\mathrm{CFT}}_D$ are then related to branes wrapped on volume minimizing cycles in the bulk, i.e., the Euclidean continuation of a black hole horizon. We illustrate with some representative examples, including gravity in ${\mathrm{AdS}}_3$, duality/triality defects in four-dimensional $\mathcal{N}=4$ super Yang-Mills theory, and the dual of R-symmetry operators probing five-dimensional Bogomol’nyi–Prasad–Sommerfield black holes.

We glue together two copies of pure anti–de Sitter (AdS) spacetime along their conformal boundaries creating a manifold without boundaries. The resulting space, which in dimension $d+2$ we denote by $\mathrm{A}\mathrm{d}{\mathrm{S}}_{\pm }^{d+2}$, has the topology of $S^2\times {\mathrm{\Sigma }}^d$, where ${\mathrm{\Sigma }}^d$ is a $d$ manifold without boundary. Acting with ${\mathbb{Z}}_n$ on the $S^2$ factor amounts to coupling a pair of membranes at the north and south poles of the two-sphere. Moreover, extending the domain of the two-sphere polar coordinate from $[0,\pi ]$ to the interval $[0,(2N-1)\pi ]$, where $N>1$, enables the coupling of one stack of $N$ coincident membranes at each pole of the two-sphere ($2N$ membranes in total). Assuming the existence of a quantum gravity theory on the glued spacetime, we compute the classical approximation of the entanglement entropy across an entangling surface consisting of the two antipodal stacks of membranes. We find that the resulting entropy exhibits a boundary cutoff divergence that can be canceled by taking the limit of an infinite number of membranes. This large-$N$ cancelation—possible only in the doubled, extended geometry without boundaries—yields a finite, universal quarter-area law. The calculation does not require details of the quantum theory other than its infrared limit, which we assume to be Einstein gravity.

This article investigates quantum entanglement generated within a one-dimensional cavity where one boundary undergoes prescribed acceleration, a setup designed to mimic aspects of Hawking radiation. We quantify quantum correlations using logarithmic negativity for bipartitions, where subsystem $A$ is a given mode and subsystem $B$ is the rest of the system. For initial pure states, we also consider a given mode and reconstruct its partner using the Hotta-Schützhold-Unruh formula, obtaining identical results. Interestingly, this last method offers notable computational efficiency. However, partner modes do not commute, due to the nontrivial multimode entanglement structure. Hence, a pairwise description will not be suitable for describing the full system. Besides, our findings reveal that the expanding cavity effectively acts as a squeezing device, with Hawking-partner pairs largely behaving as two-mode squeezed states. We checked that, in our setting, purification of Hawking modes is predominantly a low-energy process, with high-energetic particles contributing negligibly to the partner modes. Indeed, in both small and large acceleration regimes of the boundaries, quantum entanglement decreases toward the ultraviolet modes, indicating that higher-energy particles are more challenging to entangle and hence less probable to contribute in the purification process. Besides the initial vacuum state, we also consider one-mode squeezed and two-mode squeezed states, in order to confirm if quantum entanglement can be stimulated. Moreover, we analyze its robustness against initial thermal noise. Our analysis is based on numerical simulations and does not assume any approximation beyond the validity of our numerical algorithms. We conclude with a discussion about the possible implementation and observation of our results in the laboratory.

We compute the propagators of Bose and Dirac fields in four-dimensional Euclidean space in the presence of an external magnetic field, using a hybrid formulation that combines the Ritus and Schwinger methods. This approach yields explicit expressions for both propagators in coordinate and momentum space. By performing a suitable gauge transformation, we eliminate the components of the propagators that break translation invariance. We further derive the Matsubara frequencies of the fields within a toroidal topology. The resulting framework provides a unified mathematical structure that incorporates thermal and finite-volume effects in Green’s functions under various boundary conditions, while simultaneously offering an analytically tractable representation of all Landau levels.

We generalize the Oppenheimer-Snyder model of gravitational collapse by considering a broader class of static, spherically symmetric exterior spacetimes, with an interior geometry described by a Friedmann-Lemaître-Robertson-Walker (FLRW) geometry. Using Painlevé-Gullstrand (PG) coordinates for the spatially flat interior geometry ($k=0$) and a Novikov-like coordinate system for the spatially closed geometry ($k=1$), we ensure a smooth transition between the interior and exterior of the collapsing star. By providing general formulas, we analyze how apparent and event horizons form during the collapse and examine whether the matter satisfies standard energy conditions. For both $k=0$ and $k=1$ cases, we study explicit examples such as Schwarzschild, Schwarzschild–AdS/dS, and Reissner-Nordström (RN) black holes, taking into account the effects of the cosmological constant and electric charge. These factors significantly influence the collapse process and can impose constraints on the physical parameters. Our analysis leads to two important results: first, to form a black hole, there is a minimum or critical initial radius for the star to begin collapsing. Second, we propose a conjecture of an inequality regarding the event horizon formation time, starting from the critical radius, namely $\mathrm{\Delta }{T}_{\mathrm{eh}}\le 19M/6$. The upper bound is saturated by the Schwarzschild black hole.

We analyze a new class of static, smooth geometries in five-dimensional supergravity, dubbed $\mathcal{W}$-solitons. They carry the same mass and charges as four-dimensional Reissner-Nordström-like black holes but replace the horizon with a Kaluza-Klein bubble supported by electromagnetic flux. These solutions provide analytically tractable prototypes of black hole microstates in supergravity, including a new, relevant neutral configuration involving a massless axion field. Focusing on photon scattering and scalar perturbations, we compute their key observables, aiming to identify mesoscopic observables. We find that $\mathcal{W}$-solitons feature a single photon sphere, qualitatively similar to that of the black hole but with quantitative differences. They have only short-lived quasinormal modes, as black holes, while long-lived echo modes seen in other ultracompact horizonless objects are absent. As a result, the ringdown closely resembles that of a black hole while still showing sizable deviations. The latter are at the $\mathcal{O}(10\%)$ level, compatible with the recent measurement of GW250114 and potentially falsifiable in the near future. Finally, we show that $\mathcal{W}$-solitons are stable under scalar perturbations. Our results underscore the qualitative similarities between $\mathcal{W}$-solitons and black holes, reinforcing their relevance as smooth black hole microstate prototypes.