As they cool, white dwarfs pass through a period of primarily steady periodic luminosity variation. Recent data from the Kepler space telescope revealed unusual smaller aperiodic flares and larger multiperiodic flares in the white dwarf KIC 4552982. Here, these bursts are interpreted using the same simple model that describes fluctuations in magnets and earthquakes. These results show how tools from statistical physics can be used to interpret astronomical variability at multiple scales.

The impact of feedback from galaxy formation on cosmological probes is typically quantified in terms of the suppression of the matter power spectrum in hydrodynamical compared to gravity-only simulations. In this paper, we instead study how baryonic feedback impacts halo assembly histories and thereby imprints on cosmological observables. We investigate the sensitivity of the thermal Sunyaev-Zel’dovich effect (tSZ) power spectrum, X-ray number counts, weak lensing and kinetic Sunyaev-Zel’dovich (kSZ) stacked profiles to halo populations as a function of mass and redshift. We then study the imprint of different feedback implementations in the FLAMINGO suite of cosmological simulations on the assembly histories of these halo populations, as a function of radial scale. We find that kSZ profiles target lower-mass halos ($M_{200\mathrm{m}}\sim {10}^{13.1}{M}_{\odot }$) compared to all other probes considered ($M_{200\mathrm{m}}\sim {10}^{15}{M}_{\odot }$). Feedback is inefficient in high-mass clusters with $\sim {10}^{15}{M}_{\odot }$ at $z=0$, but was more efficient at earlier times in the same population, with a $\sim 5–10\%$ effect on mass at $2<z<4$ (depending on radial scale). Conversely, for lower-mass halos with $\sim {10}^{13}{M}_{\odot }$ at $z=0$, feedback exhibits a $\sim 5–20\%$ effect on mass at $z=0$ but had little impact at earlier times ($z>2$). These findings are tied together by noting that, regardless of redshift, feedback most efficiently redistributes baryons when halos reach a mass of $M_{200\mathrm{m}}\simeq {10}^{12.8}{M}_{\odot }$ and ceases to have any significant effect by the time $M_{200\mathrm{m}}\simeq {10}^{15}{M}_{\odot }$. We put forward strategies for minimizing sensitivity of lensing analyses to baryonic feedback, and for exploring baryonic resolutions to the unexpectedly low tSZ power in cosmic microwave background observations.

We present the results of a first-principles theoretical study of the inclusive semileptonic decays of the $D_s$ meson. We performed a state-of-the-art lattice QCD calculation using the gauge ensembles produced by the Extended Twisted Mass Collaboration with dynamical light, strange and charm quarks with physical masses and employed the so-called Hansen-Lupo-Tantalo (HLT) method to extract the decay rate and the first two lepton-energy moments from the relevant Euclidean correlators. We have carefully taken into account all sources of systematic errors, including the ones associated with the continuum and infinite-volume extrapolations and with the HLT spectral reconstruction method. We obtained results in very good agreement with the currently available experimental determinations and with a total accuracy at the few-percent level, of the same order of magnitude of the experimental error. Our total error is dominated by the lattice QCD simulations statistical uncertainties and is certainly improvable. From the results presented and thoroughly discussed in this paper we conclude that it is nowadays possible to study heavy mesons inclusive semileptonic decays on the lattice at a phenomenologically relevant level of accuracy. The phenomenological implications of our physical results are the subject of a companion Letter [A. De Santis et al., Inclusive semileptonic decays of the $D_s$ meson: Lattice QCD confronts experiments, Phys. Rev. Lett. 135, 121901 (2025).].

We introduce a new, probability-level approach to calculations in scalar field particle scattering. The approach involves the implicit summation over final states, which makes causality manifest since retarded propagators emerge naturally. Novel diagrams represent algebraic terms at the probability level, akin to Feynman diagrams at the amplitude level. We conjecture a list of rules that generate all probability-level diagrams for particle scattering processes in which one is fully inclusive over final states that contain no initial-state particles. These rules are confirmed using some fixed-order examples. The inclusivity and causal structure of this formalism may offer insights into the cancellation of infrared divergences if applied to gauge theory calculations.

Dark matter could be composed of macroscopic objects with large masses and geometric cross-sections spanning many decades. We investigate the potential interaction of such “stuff-sized” dark matter by considering its interactions with asteroids, planetary rings, and terrestrial bodies. This hail of dark matter could catastrophically destroy these Solar System objects, evaporate them from their orbits, or cause substantial cratering. We estimate these effects and use them to place competitive bounds on a wide, previously unconstrained swathe of the dark matter parameter space.

Gravitational self-force (GSF) theory is a strong-gravity perturbative approach to the relativistic two-body problem, primarily developed to model extreme-mass-ratio inspirals, where one compact object is significantly more massive than the companion. However, recent advancements in GSF calculations, particularly involving second-order self-force (2GSF) results, indicated a much broader applicability across a wider range of mass ratios. These developments have motivated efforts to incorporate GSF results into the effective-one-body (EOB) framework, where they have already been successfully integrated into the state-of-the-art waveform model, SEOBNRV5, employed in recent LIGO-Virgo-KAGRA observing runs. In this work, we present SEOBNR-GSF, a nonspinning inspiral-merger-ringdown (IMR) EOB waveform model that introduces a GSF-informed EOB Hamiltonian as its central innovation. This marks the first complete IMR waveform model constructed primarily from GSF results. We show that our model outperforms inspiral waveforms from full 2GSF calculations in the intermediate-to-comparable mass regime. Furthermore, by comparing with a post-Newtonian-informed variant, SEOBNR-GSF-PN, we demonstrate that the inclusion of numerical GSF information in the Hamiltonian leads to significant improvements in model fidelity. Finally, we benchmark our model against high-accuracy, nonspinning numerical-relativity simulations from the Simulating eXtreme Spacetimes (sxs) catalog and find that its median mismatch is comparable to that of SEOBNRV5, suggesting that this approach holds promise for further enhancing future EOB waveform models.

We determine the initial condition of the Balitsky-Kovchegov (BK) evolution equation at next-to-leading order (NLO) accuracy using HERA deep inelastic scattering data. We use Bayesian inference to compare model values, derived from NLO impact factors and the BK evolution equation with kinematical constraint resumming most important higher order corrections, to precise data and to extract posterior distributions characterizing the initial condition. The total cross section and charm quark production data from HERA are found to provide stringent constraints on the posterior. These distributions quantify the uncertainty in the initial condition and serve as necessary input for propagating uncertainties to all NLO calculations within the color glass condensate framework.

In this paper, we discuss a novel top-down perspective on gauging parameters in quantum field theories (QFTs) by promoting them to partially dynamical fields. Through a generalized notion of symmetry theories, we explore the consequences of this promotion, revealing new topological defects, decompositions as well as generalized symmetry structures across various dimensions. We provide a systematic top-down derivation of symmetry theories for parameters and discuss how special types of branes, such as Euclidean branes and fluxbranes are related to gauging in the parameter space in QFTs. We illustrate our theoretical framework with two key examples: the modified instanton sum in 4D $\mathcal{N}=4$ super Yang-Mills theory and the gauging of gauge ranks in 3D ABJ(M) theories.

Theoretical studies on the memory-burden effect suggest that primordial black holes (PBHs) with masses smaller than ${10}^{15}$ grams may be viable dark matter candidates and, consequently, be potential sources of high-energy particles in the present Universe. In this paper, we investigate the evaporation of memory-burdened PBHs into high-energy gamma-rays. Differently from previous analyses, we account for the attenuation of gamma-rays caused by their interaction with background radiation at energies above ${10}^5\mathrm{GeV}$, as well as the secondary emission from the electromagnetic cascades generated during their propagation through extragalactic space. Performing a likelihood analysis with current gamma-ray data, we place new constraints on the parameter space of memory-burdened PBHs. Our results show that ultrahigh-energy diffuse gamma-ray observations set more restrictive bounds than high-energy neutrino data, particularly in scenarios with a strong memory-burden suppression of the PBH evaporation.

We evaluate the three-loop five-point pentagon-box-box massless integral family in the dimensional regularization scheme, via canonical differential equation. We use tools from computational algebraic geometry to enable the necessary integral reductions. The boundary values of the differential equation are determined analytically in the Euclidean region. To express the final result, we introduce a new representation of weight six functions in terms of one-fold integrals over the product of weight-three functions with weight-two kernels that are derived from the differential equation. Our work paves the way to the analytic computation of three-loop multileg Feynman integrals.

We introduce a novel parametrization of $B\to \pi \pi \ell \nu$ form factors relying on partial-wave decompositions and series expansions in suitable variables. We bound the expansion coefficients through unitarity and include left-hand cut contributions using established dispersive methods. The two-hadron line shapes are treated in a model-independent manner using Omnès functions, thus allowing for a data-driven determination of the expansion parameters. We study the underlying composition of the di-pion system in $B\to \pi \pi \ell \nu$ decays through fits to differential spectra of $B^{+}\to {\pi }^{+}{\pi }^{-}{\ell }^{+}\nu$ measured by the Belle experiment. In contrast to previous works, we are able to study the full phase space and are not limited to certain kinematic regions. As a consequence, we extract branching fractions for the different partial waves of the di-pion system. We find $\mathcal{B}(B^{+}\to ({\pi }^{+}{\pi }^{-}{)}_S{\ell }^{+}\nu )={2.2}_{-1.0}^{+1.4}\times {10}^{-5}$, $\mathcal{B}(B^{+}\to ({\pi }^{+}{\pi }^{-}{)}_P{\ell }^{+}\nu )={19.6}_{-2.7}^{+2.8}\times {10}^{-5}$, and $\mathcal{B}(B^{+}\to ({\pi }^{+}{\pi }^{-}{)}_D{\ell }^{+}\nu )={3.5}_{-1.1}^{+1.3}\times {10}^{-5}$. In addition, we derive predictions for the thus far unobserved $B^{+}\to {\pi }^0{\pi }^0{\ell }^{+}\nu$ decay and obtain a sizable branching fraction of $\mathcal{B}(B^{+}\to {\pi }^0{\pi }^0{\ell }^{+}\nu )={2.9}_{-0.7}^{+0.9}\times {10}^{-5}$.

In light of the evidence for dynamical dark energy (DE) found from the most recent Dark Energy Spectroscopic Instrument (DESI) baryon acoustic oscillation (BAO) measurements, we perform a nonparametric, model-independent reconstruction of the DE density evolution. To do so, we develop and validate a new framework that reconstructs the DE density through a third-degree piecewise polynomial interpolation, allowing for direct constraints on its redshift evolution without assuming any specific functional form. The strength of our approach resides in the choice of directly reconstructing the DE density, which provides a more straightforward relation to the distances measured by BAO than the equation of state parameter. We investigate the constraining power of cosmic microwave background (CMB) observations combined with supernovae (SNe) and BAO measurements. In agreement with results from other works, we find a preference for deviations from $\mathrm{\Lambda }\mathrm{CDM}$, with a significance of $2.4\sigma$ when using the Dark Energy Survey Year 5 (DESY5) SNe data, and $1.3\sigma$ with PantheonPlus. In all the cases we consider, the derived DE equation of state parameter presents evidence for phantom crossing. By investigating potential systematic effects in the low-redshift samples of DESY5 observations, we confirm that correcting for the offset in apparent magnitude with respect to PantheonPlus data, as suggested in previous studies, completely removes the tension. Furthermore, we assess the risk of potentially overfitting the data by changing the number of interpolation nodes. As expected, we find that with lesser nodes we get a smoother reconstructed behavior of the DE density, although with similar overall features. The pipeline developed in this work is ready to be used with future high-precision data to further investigate the evidence for a nonstandard background evolution.

Ultralight axions (ULAs) with masses ${10}^{-33}\lesssim m/\mathrm{eV}\lesssim {10}^{-12}$ are well motivated in string-inspired models and can be part or all of the dark energy or the dark matter in this range. Since the ULA field oscillates at a frequency $m$ that can be much larger than the expansion rate $H$, accurate and efficient calculation of cosmological observables requires an effective time averaged treatment. While these are well-established for $m\gg 10H_{\mathrm{eq}}$, the Hubble rate at matter radiation equality, here we extend and develop these techniques to cover the mass range ${10}^{-33}\lesssim m/\mathrm{eV}\lesssim {10}^{-18}$. We implement this technique in a full cosmological Boltzmann code (axiecamb) with numerical precision sufficiently accurate for current and next-generation cosmic microwave background, as well as large-scale structure data analysis. New effects including the time averaging of metric perturbations and hydrostatic equilibrium of the effective fluid result in many orders of magnitude improvements for power spectra accuracy over some previous treatments such as axioncamb in some extreme regions of parameter space and order unity changes of the ULA effects near $\mathrm{\Lambda }\mathrm{CDM}$ models. These improvements may impact the specific model parameters that have been suggested might resolve various tensions in $\mathrm{\Lambda }\mathrm{CDM}$ at a comparable level.

In gamma-ray astronomy and cosmic-ray physics, the continuous approximation of inverse Compton scattering (ICS) is widely adopted to model the evolution of electron energy. However, when the initial electron energy approaches $\sim 100\mathrm{TeV}$, the discrete nature of ICS becomes prominent, and the energy of evolved electrons should be considered as a broad distribution rather than a deterministic value. By simulating the evolution paths of individual electrons under ICS, we capture this discrete nature and demonstrate that when the electron injection spectrum exhibits a high-energy cutoff, the correct discrete treatment yields a higher cutoff energy in the evolved spectrum compared to the continuous approximation. Applying the discrete ICS treatment to interpret the gamma-ray spectrum of the Geminga pulsar halo measured by the High Altitude Water Cherenkov Gamma-Ray Observatory (HAWC), we find that the inferred cutoff energy of the injection spectrum is correspondingly lower than that derived using the continuous approximation at a 95% confidence level. This suggests that the systematic bias introduced by the approximation has exceeded the measurement precision. We also expect the application of the discrete ICS correction in the peta electron volt (PeV) regime using the ultrahigh-energy gamma-ray source 1LHAASO $\mathrm{J}1954+2836\mathrm{u}$ as a case study, pointing out that adopting the continuous approximation may considerably overestimate the electron acceleration capability of the source.

Six-dimensional chiral gauged Einstein-Maxwell supergravity admits a two-parameter rotating dyonic string solution whose near horizon limit is the direct product of three-dimensional Anti-De Sitter space and a squashed three-sphere $S^3$. For a particular relation between the two parameters, the solution preserves $1/2$ supersymmetry. We determine the complete Kaluza-Klein spectrum of the theory around these ${\mathrm{AdS}}_3$ backgrounds. For the supersymmetric backgrounds, the states organize into infinite towers of long and short multiplets of $\mathrm{OSp}(2|2)$. In a certain limit of parameters, both the supersymmetric and the nonsupersymmetric spectra exhibit scale separation. In the latter case there are five topologically massive vectors and five scalars retaining finite masses with integer conformal dimensions, and in the supersymmetric case there are supersymmetric partners with half integer conformal dimensions, while all other masses diverge.

Cosmological scalar fields coupled to the Standard Model drive temporal variations in the fundamental constants that grow with redshift, positioning the early Universe as a powerful tool to study such models. We investigate the dynamics and phenomenology of coupled scalars from the early Universe to the present to consistently leverage the myriad searches for time-varying constants and the cosmological signatures of scalars’ gravitational effects. We compute the in-medium contribution from Standard Model particles to the scalar’s dynamics and identify only a limited range of couplings for which the scalar has an observable impact on the fundamental constants without either evolving before recombination or gravitating non-negligibly. We then extend existing laboratory and astrophysical bounds to the hyperlight scalar regime. We present joint limits from the early and late Universe, specializing to hyperlight, quadratically coupled scalars that modulate the mass of the electron or the strength of electromagnetism and make up a subcomponent of the dark matter today. Our dedicated analysis of observations of the cosmic microwave background, baryon acoustic oscillations, and type Ia supernovae provides the most stringent constraints on quadratically coupled scalars with masses from ${10}^{-28.5}$ to $\sim {10}^{-31}\mathrm{eV}$, below which quasar absorption spectra yield stronger bounds. These results jointly limit hyperlight scalars that comprise a few percent of the current dark matter density to near- or subgravitational couplings to electrons or photons.

We investigate black hole quasinormal modes using the exact Wentzel–Kramers–Brillouin (WKB) method. We perform an analytic continuation from the horizon to infinity along the positive real axis of the radial coordinate and impose appropriate boundary conditions at these asymptotic positions. We clarify the role of previously overlooked logarithmic spirals of Stokes curves and branch cuts emerging from the horizon. We carefully reformulate the derivation of the quasinormal mode conditions using the exact WKB analysis, incorporating the contributions from these features into the calculation. We successfully derive correct results for both solvable model examples and the Schwarzschild spacetime. Our formulation enjoys straightforward extensions to other background geometries as well as a wide range of other physical systems.

Sudden violations of the slow-roll regime during inflation, a natural prediction of many UV-complete inflationary models, give rise to sharp features in the primordial power spectrum. At large scales, these features provide a unique window into the physics of inflation, with constraints primarily derived from cosmic microwave background observations of linearly evolved primordial fluctuations. However, on smaller scales, it is less clear whether primordial features would survive the late-time nonlinear cosmological evolution, as they are expected to be washed out by mode coupling. In this paper, we run dedicated $N$-body simulations to tackle this question. We demonstrate that, while oscillatorylike patterns are erased over time by nonlinearities, signatures of primordial sharp features can persist through the nonlinear regime of structure formation. Those take the form of a localized power enhancement or decrease in the matter power spectrum—whose amplitude and position can in principle be used to recover the scale of the primordial feature—and an oscillatory pattern in the halo mass function. While these findings highlight the power for constraining inflationary physics at small scales, they also show the challenges posed by potential degeneracies with other physical processes relevant in the nonlinear regime of structure formation such as noncold dark matter candidates. Our results open new avenues for probing inflationary physics in large scale structures and galactic physics and emphasize the need for refined theoretical tools to robustly constrain primordial features.

Using the full four-year SPTpol $500{\mathrm{deg}}^2$ dataset in both the 95 and 150 GHz frequency bands, we present measurements of the temperature and $E$-mode polarization of the cosmic microwave background (CMB), as well as the $E$-mode polarization autopower spectrum ($EE$) and temperature-$E$-mode cross-power spectrum ($TE$) in the angular multipole range $50<\ell <8000$. We find the SPTpol dataset to be self-consistent, passing several internal consistency tests based on maps, frequency bands, bandpowers, and cosmological parameters. The full SPTpol dataset is well-fit by the $\mathrm{\Lambda }\mathrm{CDM}$ model, for which we find $H_0=70.48\pm 2.16\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$ and ${\mathrm{\Omega }}_m=0.271\pm 0.026$, when using only the SPTpol data and a Planck-based prior on the optical depth to reionization. The $\mathrm{\Lambda }\mathrm{CDM}$ parameter constraints are consistent across the 95 GHz-only, 150 GHz-only, $TE$-only, and $EE$-only data splits. Between the $\ell <1000$ and $\ell >1000$ data splits, the $\mathrm{\Lambda }\mathrm{CDM}$ parameter constraints are borderline consistent at the $\sim 2\sigma$ level. This consistency improves when including a parameter $A_L$, the degree of lensing of the CMB inferred from the smearing of acoustic peaks. When marginalized over $A_L$, the $\mathrm{\Lambda }\mathrm{CDM}$ parameter constraints from SPTpol are consistent with those from Planck. The power spectra presented here are the most sensitive measurements of the lensed CMB damping tail to date for roughly $\ell >1700$ in $TE$ and $\ell >2000$ in $EE$.

The solar steady emission in gamma rays is due to the interactions of Galactic cosmic rays with the solar atmosphere and with the low-energy solar photon field via inverse Compton scattering. The emission is sensitive to the magnetic field nearby the Sun and to the cosmic-ray transport in the magnetic field in the inner Solar System. Modeling the inverse Compton emission in the presence of a magnetic field is, therefore, crucial to better interpret the observations. In a previous work, we have presented a comprehensive calculation of the secondary productions due to the collision of cosmic rays with the solar atmosphere in the presence of magnetic fields. In this paper, we present a general approach to calculate the (anisotropic) inverse Compton scattering in a 3D Monte Carlo simulation, also in the presence of magnetic and electric fields. After a short review of the scattering process of photons with electrons, examples of inverse Compton emission are presented, including the predictions for the Sun.