Cosmological domain walls appear in many well-motivated extensions to the standard model of particle physics. If produced, they quickly enter into a self-similar scaling regime, where they are capable of efficiently sourcing a stochastic background of gravitational waves. In order to avoid a cosmological catastrophe, they must also decay before their enormous energy densities can have adverse effects on background dynamics. Here, we provide a suite of lattice simulations to comprehensively study the gravitational wave signatures of the domain wall network during this decay phase. The domain walls are initially formed through spontaneous breaking of a ${\mathbb{Z}}_2$ symmetry, and subsequently decay through the action of a small bias term which causes regions of false vacuum to collapse. We find that gravitational waves are produced in abundance throughout this collapsing phase, leading to a shift in the peak frequency and increase in the overall amplitude of the spectrum by an $\mathcal{O}(100)$ factor when compared against simple analytic arguments. Importantly, we also find that the characteristic frequency of emitted gravitational waves increases as the network decays, which leads to a softening of the high frequency spectral index. This high frequency spectrum therefore carries key information related to the dynamics of the collapsing phase, and can be used to discriminate between different domain wall scenarios using upcoming data.

We analyze the basic cosmological effects of a population of timelike boundaries—a form of nontrivial spacetime topology—containing a boundary layer of quantum stress-energy. This accumulation of vacuum fluctuations of quantum fields can be consistently negative and UV sensitive, providing an additional source of cosmic energy density strong enough to compete with matter and dark energy. For boundary conditions enabling a solution with fixed comoving boundary size, this effect contributes a qualitatively new term to the Friedmann equation determining the expansion history, scaling like $-1/a$ for scale factor $a$. It naturally dominates at relatively late times ($a\approx 1/2$), while leaving intact well-measured early Universe physics such as big bang nucleosynthesis and recombination. For a wide window of parameters, the boundaries can be larger than the Planck length throughout their history, back through the start of inflation at any viable scale. We analyze cosmic microwave background and baryon acoustic oscillation datasets (Planck, Atacama Cosmology Telescope, and Dark Energy Spectroscopic Instrument) allowing for this component, finding a slight preference ($\sim 2\sigma$) and a relaxation of current tensions in the data (including the neutrino mass) in a physical manner. This novel parameter fits into a larger space of physical parameters beyond-$\mathrm{\Lambda }$ cold dark matter (CDM) that may serve this role, including negative spatial curvature, which may also be motivated by topological considerations and chaotic dynamics. Finally, we comment on additional phenomenological prospects for testing for this form of topology in the Universe.

$E_G$ is a summary statistic that combines cosmological observables to achieve a test of gravity that is relatively model independent. Here, we consider the power of a measurement of $E_G$ using galaxy-galaxy lensing and galaxy clustering with sources from the Vera C. Rubin Observatory’s Legacy Survey of Space and Time (LSST), and lenses from the Dark Energy Spectroscopic Instrument (DESI). We first update the theoretical framework for the covariance of $E_G$ to accommodate this Stage IV scenario. We then demonstrate that $E_G$ offers in principle a model-agnostic test of gravity using only linear-scale information, with the caveat that a careful treatment of galaxy bias is required. We finally address the persistent issue of $E_G$’s theoretical dependence on the measured value of ${\mathrm{\Omega }}_{\mathrm{M}}^0$. We propose a framework that takes advantage of the posterior predictive test to consistently incorporate uncertainty on ${\mathrm{\Omega }}_{\mathrm{M}}^0$ in tests of gravity with $E_G$, which should be of general use beyond the LSST + DESI scenario. Our forecasting study using this method shows that the prior information available for ${\mathrm{\Omega }}_{\mathrm{M}}^0$ is instrumental in determining the power of $E_G$ in the LSST + DESI context. For the full survey dataset, with priors on ${\mathrm{\Omega }}_{\mathrm{M}}^0$ from existing cosmic microwave background data, we find that for some modified gravity scenarios considered, we are likely to be able to reject the general relativity null hypothesis.

Using high-resolution athenak simulations of a twisted toroidal flux tube, we study the flux emergence of magnetic structures in the shear layer of a hot massive neutron star typical of a binary neutron star remnant. High-resolution simulations demonstrate that magnetic buoyant instabilities allow for emergence only for extremely large magnetic fields significantly exceeding ${10}^{17}\mathrm{G}$, and more typical fields around ${10}^{16}\mathrm{G}$ are instead dominated by hydrodynamic effects. Because merger remnants tend to be stable against hydrodynamic convection, our work places strong limitations on the mechanisms by which massive binary neutron star remnants can produce the magnetically-driven outflows needed to power jets.

The Vera C. Rubin Observatory has now seen first light, and over a 10 year duration, Legacy Survey of Space and Time (LSST) is projected to catalog tens of millions of quasars, many of which are expected to be associated with subparsec supermassive black hole binaries (SMBHBs). Out of these SMBHBs, up to thousands of relatively massive binary-quasars are expected to exhibit gravitational self-lensing flares (SLFs) that last for at least 20–30 days. We assess the effectiveness of the Lomb-Scargle (LS) periodogram and matched filters (MFs) as methods for systematic searches for these binaries, using toy-models of hydrodynamical, Doppler, and self-lensing variability from equal-mass, eccentric SMBHBs. We inject SLFs into random realizations of damped random walk (DRW) lightcurves, representing stochastic quasar variability, and compute the LS periodogram with and without the SLF. We find that periodograms of $\mathrm{SLF}+\mathrm{DRW}$ light-curves do not have maximum peak heights that could not arise from DRW-only periodograms. On the other hand, the matched filter signal-to-noise ratio (SNR) can distinguish SLFs from noise even with LSST-like cadences and DRW noise. Furthermore, we develop a three-step procedure with matched filters, which can also recover injected binary parameters from these light-curves. We expect this method to be computationally efficient enough to be applicable to millions of quasar light-curves in LSST.

We respond to comments [D. Pitonyak, C. Cocuzza, A. Metz, A. Prokudin, and N. Sato, preceding Comment, Phys. Rev. D 113, 038901 (2026)] about our article, [Phys. Rev. D 111, 056001 (2025)]. We stand by our conclusions and defend them against the criticisms.

We make several comments on the recent work in Rogers et al. [Phys. Rev. D 111, 056001 (2025)] while also reaffirming and adding to the work in Pitonyak et al. [Phys. Rev. Lett. 132, 011902 (2024)]. We show that the factorization formula for $e^{+}{e}^{-}\to (h_1\cdots h_n)X$ in Rogers et al. is equivalent to a version one can derive using the definition of a $n$-hadron fragmentation function (FF) introduced in Pitonyak et al.. In addition, we scrutinize how to generalize the number density definition of a single-hadron FF to a $n$-hadron FF, arguing that the definition given in Pitonyak et al. should be considered the standard one while the definition in Rogers et al. has no clear interpretation. We also emphasize that the evolution equations for dihadron FFs (DiFFs) in Pitonyak et al. have the same splitting functions as those for single-hadron FFs. Therefore, the DiFF (and $n$-hadron FF) definitions in Pitonyak et al. have a natural number density interpretation and, contrary to what is stated in Rogers et al., are consistent with collinear factorization using the standard hard factors and evolution kernels.

We study the photon emission by charged spinless particles with phase vortices and an orbital angular momentum (OAM) projection in longitudinal electric and magnetic fields within the scalar QED. A realistic wave packet of an electron or ion accelerated by a radiofrequency wave locally feels a constant and spatially homogeneous field, which allows us to develop an effective model for losing the angular momentum of the vortex particle due to photon emission. For the fields typical for accelerator facilities, we find that an effective lifetime of the vortex state greatly exceeds the acceleration time. This proves that the acceleration of vortex electrons, ions, muons, and so forth to relativistic energies is possible in conventional linacs, the OAM losses due to the photon emission are mostly negligible, and that the vortex quantum state is highly robust against these losses.

We discuss a one-quark state in the confinement phase near a reflective chromometallic boundary both at finite and zero temperature. Using numerical simulations of lattice Yang-Mills theory, we show that the test quark is confined to the neutral mirror by an attractive potential of the Cornell type, suggesting the existence of a mirror-bound one-quark state, a “quarkiton.” Surprisingly, the tension of the string spanned between the quark and the mirror is lower than the fundamental string tension. The quarkiton state exhibits a partial confinement: while the quark is localized in the vicinity of the mirror, it can still travel freely along it. Such quarkiton states share similarity with the surface excitons in metals and semiconductors that are bound to their negatively charged images at a boundary. The quarkitons can exist at the hadronic side of the phase interfaces in QCD that arise, for example, in the thermodynamic equilibrium of vortical quark-gluon plasma.

In this work we study the axion/axion-like particle production from the lepton–nucleon scattering in the low-energy region, i.e., the $\ell N\to \ell Na$ processes, $\ell$ being the electron or muon and $N$ the proton or neutron. We simultaneously include three different types of axion interaction couplings within the chiral effective field theory, namely the axion–nucleon–nucleon couplings $g_{aNN}$, axion–photon–photon coupling $g_{a\gamma \gamma }$, and axion–photon–vector meson resonance couplings $g_{\rho a\gamma }$ and $g_{\omega a\gamma }$. Vast inputs from the lattice QCD and hadron phenomenological studies are used to fix the unknown couplings. The relative strengths of different axion interactions in the $\ell N\to \ell Na$ processes are then revealed. We provide detailed predictions for the differential cross sections with respect to various angles and axion energy, as well as the total cross sections in the low-energy region around production thresholds, both for the Kim-Shifman-Vainstein-Zakharov (KSVZ) and Dine-Fischler-Srednicki-Zhitnitsky (DFSZ) axion models.

Neutron star glitches—sudden increases in rotational frequency—are thought to result from angular momentum transfer via quantized vortices in the superfluid core. To investigate the underlying superfluid dynamics, we employ a two-dimensional rotating atomic Bose-Einstein condensate described by a damped Gross-Pitaevskii equation with an imposed pinning potential that serves as a simplified analog of a crust. Within this minimal framework, we examine the emergence and evolution of turbulent vortex motion following impulsive perturbations reminiscent of glitchlike forcing. Our simulations reveal a transient Kolmogorov-like turbulent cascade ($k^{-5/3}$) that transitions to a Vinen-like scaling ($k^{-1}$). We identify an anomalous secondary injection mechanism driven primarily by quantum pressure, which can sustain turbulent fluctuations in such a system. By tuning the damping coefficient $\gamma$, we determine an optimal regime for energy transfer. While idealized, these findings illustrate how quantum turbulence with multiple scaling regimes can arise in pinned, rotating superfluids, and they suggest possible qualitative connections to vortex-mediated dynamics in neutron stars and other astrophysical superfluid systems.

Four-derivative heterotic supergravity (without gauge fields) reduced on a $p$-dimensional torus leads to half-maximal supergravity coupled to $p$ vector multiplets, and it is known that removing the vector multiplets is a consistent truncation of the theory. We find a new consistent truncation of four-derivative heterotic supergravity on a torus that keeps the vector multiplets and precisely reproduces the bosonic action of heterotic supergravity (with heterotic gauge fields). We show that both truncations have an $O(d+p,d)$ symmetry when reduced on a $d$-dimensional torus and demonstrate how this embeds in the $O(d+p,d+p)$ symmetry that one gets from reducing on a ($d+p$)-dimensional torus without truncation. We then use our new truncation to obtain four-derivative corrections to the Kerr-Sen solution and compute thermodynamic quantities and multipole moments. Finally, we compare the Kerr-Sen solutions of the actions corresponding to the two different choices of truncation with the Kerr solution, the Kerr-Newman solution, and each other, and show that they have distinct four-derivative multipole structures.

We carefully examine the exact analytic spectrum of quasinormal modes of general black holes in the so-called subtracted geometry of maximally supersymmetric supergravity. These black holes have the same area and surface gravity at both the outer and inner horizons as asymptotically flat Kerr black holes. We proceed to explore the relationship with conformal field theories that describe horizon physics of these black holes. As a consequence, we show that it is consistent to view the horizon area of these black holes as being quantized in units of $8\pi l_{\mathrm{Pl}}^2$.

We study the algebraic structure of one-loop Bern-Carrasco-Johansson numerators in Yang-Mills and related theories. Starting from the propagator matrix that connects color-ordered integrands to numerators, we identify the consistency conditions that ensure the existence of Jacobi-satisfying numerator solutions and determine the unique construction. The relation between one-loop numerators and forward-limit tree numerators is clarified, together with the additional physical conditions required for a consistent double-copy interpretation. We propose a two-step expansion strategy for obtaining explicit one-loop numerators. The Yang-Mills integrand is first decomposed into scalar-loop Yang-Mills-scalar building blocks, which are then expanded into biadjoint scalar integrands. We derive explicit results for up to three external gluons, showing how the kinematic consistency conditions uniquely determine the coefficients in each case. Similar results for Einstein-Yang-Mills and gravity amplitudes are also presented.

We present the first fully nonlinear causality constraints in $D=3+1$ dimensions for Israel-Stewart theory in the presence of energy and number diffusion in the Eckart and Landau hydrodynamic frames, respectively. These constraints are algebraic inequalities that make no assumption on the underlying geometry of the spacetime or the equation of state. In order to highlight the distinct physical and structural behavior of the two hydrodynamic frames, we discuss the special ultrarelativistic ideal gas equation of state considered in earlier literature in $D=1+1$ dimensions, and show that our general $D=3+1$ constraints reduce to their results upon an appropriate choice of angles. For this equation of state in both $D=1+1$ and $D=3+1$ dimensions one can show that: (i) there exists a region allowed by nonlinear causality in which the baryon current transitions into a spacelike vector in the Landau frame, and (ii) an analogous argument shows that the solutions of the Eckart frame equations of motion never violate the dominant energy condition, assuming nonlinear causality holds. We then compare our results with those from linearized Israel-Stewart theory and show that the linear causality bounds fail to capture the new physical constraints on energy and number diffusion that are successfully obtained through our nonlinear causality approach.

We examine the conditions under which entanglement can be extracted from a quantum field using two localized modes A and B (detector modes). Building upon Simon’s entanglement criterion [1] for bipartite Gaussian states, we reformulate the condition in terms of commutators between the canonical operators of detector mode B and the partner mode P of detector mode A. This reformulation allows us to derive a no-go theorem for entanglement harvesting in certain settings, including uniformly accelerating detectors. Drawing upon the known correspondence between the Unruh effect and Hawking radiation, our result implies the absence of quantum correlations between “real particles” emitted as Hawking radiation.

We develop the quantization of a recently proposed model describing a totally antisymmetric rank-$p$ tensor-spinor field (a fermionic $p$-form theory) in $d$-dimensional anti–de Sitter (AdS) space. The model provides a new nontrivial example of a reducible gauge theory, in which gauge transformations are linearly dependent and the degree of reducibility increases with $p$. It is well-known that in such cases the standard Faddeev-Popov-DeWitt prescription for the generating functional is not applicable. We quantize the fermionic $p$-form theory using the general Batalin-Vilkovisky formalism, employing two distinct gauge fermions associated with gauge-fixing functions of different admissible ranks, confirming the independence from the gauge choice. As a result, we obtain the quantum effective action in terms of a sequence of functional determinants corresponding to specific Dirac-like operators on AdS space.

In this work, we study the time evolution of radial kinks in the background of boson stars. In particular, we consider two types of boson stars: the massive boson star and the solitonic boson star. For each boson star, we study the dynamics of the kinks with four different compactnesses. We observe that the greater the compactness is, the slower the kinks move toward the origin of the boson stars, indicating that the compactness will hinder the kinks to collide with the origin. Additionally, it is found that when the boson star is highly compact, a new kink may turn out after the kink colliding with the origin, instead of immediately dissipating into the background. From this, we then propose that the radial kinks may potentially serve as a means to probe the internal structures of dense astrophysical objects, even the interior structure of black holes.

It is well-known that Reissner-Nordström black holes cannot support spatially regular configurations of minimally coupled massive scalar fields in their exterior regions. But can they do so in their interior regions? In the present compact paper we explicitly prove that the answer to this physically interesting question is ‘yes’. In particular, it is proved that the interior spacetimes of extremal Reissner-Nordström black holes can support static (zero-frequency) bound-state configurations of linearized massive scalar fields whose characteristic eigenfunctions are regular throughout the entire interval $r\in [0,r_{\mathrm{H}}]$. Interestingly, solving analytically the Klein-Gordon wave equation for the massive scalar fields in the interior region of a maximally charged eternal black hole, we identify a discrete set $\{{\mu }_n(r_{\mathrm{H}},l){\}}_{n=0}^{n=\infty }$ of field masses that characterize antiresonant modes of the composed black-hole-field system, a unique family of massive scalar fields that cannot be supported inside the extremal black hole (here $r_{\mathrm{H}}$ is the horizon radius of the black hole and $\{\mu ,l\}$ are, respectively, the proper mass of the scalar field and its angular harmonic index).