Violating the slow-roll regime during the final stages of inflation can significantly enhance curvature perturbations, a scenario often invoked in models producing primordial black holes and small-scale scalar induced gravitational waves. When perturbations are enhanced, one approaches the regime in which tree-level computations are insufficient, and nonlinear corrections may become relevant. In this work, we conduct lattice simulations of ultraslow-roll (USR) dynamics to investigate the significance of nonlinear effects, both in terms of backreaction on the background and in the evolution of perturbations. Our systematic study of various USR potentials reveals that nonlinear corrections are significant when the tree-level curvature power spectrum peaks at ${\mathcal{P}}_{\zeta }^{\max }=\mathcal{O}({10}^{-3})-\mathcal{O}({10}^{-2})$, with $5\%–20\%$ corrections. Larger enhancements yield even greater differences. We find a simple universal relation between simulation and tree-level quantities $\dot{\varphi }={\dot{\varphi }}_{\mathrm{tree}}(1+\sqrt{{\mathcal{P}}_{\zeta ,\text{tree}}^{\max }})$ at the end of the USR phase, which is valid in all cases we consider. Additionally, we explore how nonlinear interactions during the USR phase affect the clustering and non-Gaussianity of scalar fluctuations, crucial for understanding the phenomenological consequences of USR, such as scalar-induced gravitational waves and primordial black holes. Our findings demonstrate the necessity of going beyond leading order perturbation theory results, through higher-order or nonperturbative computations, to make robust predictions for inflation models exhibiting a USR phase.

Ultralight dark matter (UDM) may manifest itself through oscillating fundamental constants of normal matter. These can be experimentally searched for by implementing two dissimilar oscillators producing a beat between their frequencies and analyzing the beat-frequency time series for the presence of any temporal oscillations. Typically, the time series of such a detector contains contributions from nonstationary noise. In order to reduce the influence of such noise we propose and demonstrate paired detectors: two nominally identical detectors whose signals are synchronously recorded. The cross-spectrum of the two individual beat time series is then analyzed for UDM signatures. This approach permits us to suppress spurious signals appearing in uncorrelated fashion in either detector. We furthermore demonstrate detectors that are based on a vibrational molecular transition, which are advantageous due to their larger sensitivity to oscillations of the nuclear masses. The analysis of 274 hours of data yielded improved bounds for the coupling constants of UDM to nuclear mass and to electron mass in the frequency ranges 10–500 Hz and 10–122 kHz, with improvement factors between 6 and 10. These bounds are currently the strongest. Similar bounds are obtained for the fine-structure constant. The present approach may be generalized to large ensembles of detectors.

The baryonic feedback effect is considered as a possible solution to the so-called $S_8$ tension indicated in cosmic shear cosmology. The baryonic effect is more significant on smaller scales, and it affects the cosmic shear two-point correlation functions (2PCFs) with different scale and redshift dependencies from those of the cosmological parameters. In this paper, we use the Hyper Suprime-Cam Year 3 (HSC-Y3) data to measure the cosmic shear 2PCFs (${\xi }_{\pm }$) down to 0.28 arcminutes, taking full advantage of the high number density of source galaxies in the deep HSC data, to explore a possible signature of the baryonic effect. While the published HSC analysis used the cosmic shear 2PCFs on the angular scales that are sensitive to the matter power spectrum at $k\lesssim 1h{\mathrm{Mpc}}^{-1}$, the smaller-scale HSC cosmic shear signal allows us to probe the signature of the matter power spectrum up to $k\simeq 20h{\mathrm{Mpc}}^{-1}$. Using the accurate emulator of the nonlinear matter power spectrum, darkemulator2, we show that the dark-matter-only model can provide an acceptable fit to the HSC-Y3 2PCFs down to the smallest scales. In other words, we do not find any clear signature of the baryonic effects, or we do not find a systematic shift in the $S_8$ value with the inclusion of the smaller-scale information as would be expected if the baryonic effect were significant. Alternatively, we use a flexible six-parameter model of the baryonic effects, which can lead to both enhancement and suppression in the matter power spectrum compared to the dark-matter-only model, to perform the parameter inference of the HSC-Y3 2PCFs. We find that the small-scale HSC data allow only a fractional suppression of up to 5% in the matter power spectrum at $k\sim 1h{\mathrm{Mpc}}^{-1}$, which is not sufficient to reconcile the $S_8$ tension. Finally, we discuss that ${\xi }_{-}$ on scales smaller than a few arcminutes can be used to monitor characteristic features caused by the baryonic effect if present, while ${\xi }_{\pm }$ with appropriate scale cuts can be used to constrain the cosmological parameters, simultaneously.

We present a simulation-based cosmological analysis using a combination of Gaussian and non-Gaussian statistics of the weak lensing mass (convergence) maps from the first three years of the Dark Energy Survey. We implement the following: (1) second and third moments; (2) wavelet phase harmonics; (3) the scattering transform. Our analysis is fully based on simulations, spans a space of seven $w$ Cold Dark Matter ($w\mathrm{CDM}$) cosmological parameters, and forward models the most relevant sources of systematics inherent in the data: masks, noise variations, clustering of the sources, intrinsic alignments, and shear and redshift calibration. We implement a neural network compression of the summary statistics, and we estimate the parameter posteriors using a simulation-based inference approach. Including and combining different non-Gaussian statistics is a powerful tool that strongly improves constraints over Gaussian statistics (in our case, the second moments); in particular, the figure of merit $(S_8,{\mathrm{\Omega }}_{\mathrm{m}})$ is improved by 70% ($\mathrm{\Lambda }\mathrm{CDM}$) and 90% ($w\mathrm{CDM}$). When all the summary statistics are combined, we achieve a 2% constraint on the amplitude of fluctuations parameter $S_8\equiv {\sigma }_8({\mathrm{\Omega }}_{\mathrm{m}}/0.3{)}^{0.5}$, obtaining $S_8=0.794\pm 0.017$ ($\mathrm{\Lambda }\mathrm{CDM}$) and $S_8=0.817\pm 0.021$ ($w\mathrm{CDM}$), and a $\sim 10\%$ constraint on ${\mathrm{\Omega }}_{\mathrm{m}}$, obtaining ${\mathrm{\Omega }}_{\mathrm{m}}=0.259\pm 0.025$ ($\mathrm{\Lambda }\mathrm{CDM}$) and ${\mathrm{\Omega }}_{\mathrm{m}}=0.273\pm 0.029$ ($w\mathrm{CDM}$). In the context of the $w\mathrm{CDM}$ scenario, these statistics also strengthen the constraints on the parameter $w$, obtaining $w<-0.72$. The constraints from different statistics are shown to be internally consistent (with a $p$-value>0.1 for all combinations of statistics examined). We compare our results to other weak lensing results from the first three years of the Dark Energy Survey data, finding good consistency; we also compare with results from external datasets, such as planck constraints from the cosmic microwave background, finding statistical agreement, with discrepancies no greater than $<2.2\sigma$.

The dark dimension scenario, predicting one extra mesoscopic dimension in the micron range, has emerged by applying various swampland principles to the dark energy. In this note we find that realizing the grand unification of gauge forces is highly constraining in this context. Without actually constructing any grand unified theory (GUT) models, we argue that the mere assumption of grand unification of forces in this scenario, together with the experimental bounds on massive replicas of the Standard Model gauge bosons, predicts an upper bound for the GUT scale, $M_{\mathrm{GUT}}\lesssim {10}^{16}\mathrm{GeV}$. Combined with the experimental bound on the proton lifetime, this predicts that the $X$ gauge boson mediating proton decay is a 5D solitonic string of Planckian tension stretched across a length scale $L\sim (1–10\mathrm{TeV}{)}^{-1}$ ending on gauge branes of the same diameter $\sim L$. This leads to a mass of $M_X\sim {10}^{15}–{10}^{16}\mathrm{GeV}$. In particular assuming grand unification in the dark dimension scenario results in a tower of Kaluza-Klein excitations of Standard Model gauge bosons on the gauge branes in the 1–10 TeV range. This suggests that the diameter/separation $L$ of the gauge branes correlates with both the weak scale $\sim 1/L$ near a TeV and the GUT scale $\sim M_5^{2}L$ at ${10}^{16}\mathrm{GeV}$.

We show that the Kontsevich-Segal-Witten (KSW) criterion applied to the no-boundary state constrains anisotropic deformations of de Sitter space. We consider squashed $S^3$ and $S^1\times S^2$ boundaries and find that, in both models, the KSW criterion excludes a significant range of homogeneous but anisotropic configurations. For squashed $S^3$ boundaries, the excluded range includes all surface geometries with negative scalar curvature, in line with dS/CFT reasoning. For $S^1\times S^2$ boundaries, we find that KSW selects the low-temperature regime of configuration space where the $S^1$ is sufficiently large compared to the $S^2$. In both models, the KSW criterion renders the semiclassical wave function normalizable, up to one-loop effects.

TeV halos are extended very-high-energy (VHE; 0.1–100 TeV) gamma-ray emission around middle-aged pulsars. So far they have only been found around isolated pulsars, but it has been suggested that they may also be powered by millisecond pulsars (MSPs). We searched for VHE gamma-ray emission from MSPs reported by radio and GeV gamma-ray observatories in 2565 days of data from the High Altitude Water Cherenkov (HAWC) Observatory. We found no significant emission from individual pulsars. By combining the likelihood profiles of all MSPs accessible to HAWC, our analysis suggests that the excess emission around the MSP population is consistent with a background. Our result suggests that MSPs are not as efficient as isolated pulsars in producing TeV halos. This finding has strong implications on the physics interpretation of the Galactic Center GeV excess and high-latitude Galactic diffuse emission.

We revisit particle creation in strong fields, and backreaction on those fields, from an amplitudes perspective. We describe the strong field by an initial coherent state of photons which we explicitly evolve in time, thus going beyond the background-field approximation, and then consider observables which quantify the effects of backreaction. We present expressions for the waveform, vacuum persistence probability, and number of produced photons at next-to-leading order, all of which are impacted by backreaction, along with the number and statistics of produced pairs. We find that converting between in-out (amplitude) and in-in (expectation value) expressions requires explicit resummation of an infinite number of disconnected loop diagrams.

Gravitational waves (GW) sourced by second-order primordial curvature fluctuations are among the favored models fitting the recent pulsar timing array (PTA) measurement of a stochastic GW background (SGWB). We study how spectral distortions (SDs) and anisotropies of the cosmic microwave background (CMB) can constrain such scalar fluctuations. Whereas COBE FIRAS data have no sufficient sensitivity to probe the PTA log-normal hypothesis, we show how future PIXIE-like experiments can detect the CMB SDs from the scalar-induced interpretation of the SGWB in PTA data. We finally show how the transformative synergy between PTA data and future CMB SD measurements is important for reconstructing primordial fluctuations at these small scales.

Quasinormal modes (QNMs) are usually characterized by their time dependence, with oscillations at specific frequencies predicted by black hole (BH) perturbation theory. QNMs are routinely identified in the ringdown of numerical relativity waveforms, are widely used in waveform modeling, and underpin key tests of general relativity and of the nature of compact objects—a program sometimes called BH spectroscopy. Perturbation theory also predicts a specific spatial shape for each QNM perturbation. For the Kerr metric, these are the ($s=-2$) spheroidal harmonics. Spatial information can be extracted from numerical relativity by fitting a feature with known time dependence to all of the spherical harmonic modes, allowing the shape of the feature to be reconstructed—a program initiated here and that we call “BH cartography.” Accurate spatial reconstruction requires fitting to many spherical harmonics and is demonstrated using highly accurate Cauchy-characteristic numerical relativity waveforms. The loudest QNMs are mapped, and their reconstructed shapes are found to match the spheroidal harmonic predictions. The cartographic procedure is also applied to the quadratic QNMs—nonlinear features in the ringdown—and their reconstructed shapes are compared with expectations based on second-order perturbation theory. BH cartography allows us to determine the viewing angles that maximize the amplitude of the quadratic QNMs, an important guide for future searches, and is expected to lead to an improved understanding of nonlinearities in BH ringdown.

In this paper, we prove a new nonrenormalization theorem which arises from UV/IR mixing. This theorem and its corollaries are relevant for all four-dimensional perturbative tachyon-free closed string theories which can be realized from higher-dimensional theories via geometric compactifications. As such, our theorem therefore holds regardless of the presence or absence of spacetime supersymmetry and regardless of the gauge symmetries or matter content involved. This theorem resolves a hidden clash between modular invariance and the process of decompactification, and enables us to uncover a number of surprising phenomenological properties of these theories. Chief among these is the fact that certain physical quantities within such theories cannot exhibit logarithmic or power-law running and instead enter an effective fixed-point regime above the compactification scale. This cessation of running occurs as the result of the UV/IR mixing inherent in the theory. These effects apply not only for gauge couplings but also for the Higgs mass and other quantities of phenomenological interest, thereby eliminating the logarithmic and/or power-law running that might have otherwise appeared for such quantities. These results illustrate the power of UV/IR mixing to tame divergences—even without supersymmetry—and reinforce the notion that UV/IR mixing may play a vital role in resolving hierarchy problems without supersymmetry.

Fast radio bursts (FRBs), like pulsars, display radio emission from compact regions such that they can be treated as point sources. As this radiation propagates through space, they encounter sources of lensing such as a gravitational field of massive objects or inhomogeneous changes in the electron density of cold plasma. We have developed a simulation tool to generate these lensing morphologies through coherent propagation transfer functions generated by phase coherent geometric optics on a spatial grid. In the limit an FRB can be treated as a point source, the ray paths from the FRB to the observer are phase coherent. Each image will have a time delay and magnification that will alter the emitted frequency-temporal morphology of the FRB to that which is observed. The interference of these images could also decohere the observed phase properties of the images, affecting any phase related searches such as searching for the autocorrelation of the observed FRB voltage with other images in time. We present analytic test cases to demonstrate that the simulation can model qualitative properties. We provide example multiplane lensing systems to show the capabilities of the simulation in modeling the lensed morphology of an FRB and observed phase coherence.

We propose the use of natural minerals as detectors to study the past flux of cosmic rays. This novel application of the paleo-detector technique requires a specific approach as it needs samples that have been exposed to secondary cosmic rays for a well defined period of time. We suggest here the use of the evaporites formed during the desiccation of the Mediterranean sea $\sim 6\mathrm{Myr}$ ago. These minerals have been created and exposed to the air or under a shallow water basin for $\sim 500\mathrm{kyr}$ before being quickly submerged again by a km-scale overburden of water. We show that, by looking at the damages left in the minerals by muons in cosmic ray showers, we could detect differences in the primary cosmic ray flux during that period, as the ones expected from nearby supernova explosions, below the percent-level. We show also that little to no background from radioactive contamination and other astroparticles is expected for this kind of analysis.

Fragmentation functions (FFs) are essential nonperturbative QCD inputs for predicting hadron production cross sections in high energy scatterings. In this study, we present a joint determination of FFs for light charged hadrons through a global analysis at next-to-leading order (NLO) in QCD. Our analysis incorporates a wide range of precision measurements from the LHC, as well as data from electron-positron collisions and semi-inclusive deep inelastic scatterings. By including measurements of jet fragmentation at the LHC in our global analysis, we are able to impose strong constraints on the gluon FFs. A careful selection of hadron kinematics is applied to ensure the validity of factorization and perturbative calculations of QCD. In addition, we introduce several methodological advances in fitting, resulting in a flexible parametrization form and the inclusion of theoretical uncertainties from perturbative calculations. Our best-fit predictions show very good agreement with the global data, with ${\chi }^2/N_{pt}\sim 0.90$. We also generate a large number of Hessian error sets to estimate uncertainties and correlations of the extracted FFs. FFs to charged pions (kaons and protons) are well constrained for momentum fractions down to 0.01 (0.1). Total momentum of partons carried by light charged hadrons are determined precisely. Their values for $u$, $d$ quarks and gluon saturate at about 50% for a lower cut of the momentum fraction of 0.01. Comparing our determinations to results from other groups, we find significant discrepancies, particularly for the proton fragmentation functions, as well as for gluon and unfavored quarks to pions and kaons. Pulls from individual datasets and impact of various choices of the analysis are also studied in details. Our analysis raises questions concerning existing and future experimental measurements, including the need for clarifications on the definitions of various hadron final states and the necessity of further measurements on fragmentation from heavy quarks. Additionally, we present an update of the fmnlo program used for calculating hadron production cross sections. We demonstrate the broad applications of the fmnlo program combined with our new FFs, including NLO predictions on jet charges in proton collisions and reference cross sections for heavy-ion collisions, which show good agreement with LHC data. Our FFs, including the error sets (denoted as NPC23), are publicly available in the form of LHAPDF6 grids.

We consider the scattering of high energy leptons off bound atomic electrons focusing primarily on final state interactions between the outgoing energetic electron, and the heavy residual charged “debris” in the final state. These effects are inherently absent from calculations for a free electron at rest. Coulomb exchanges are enhanced by the large number of electrons in the atomic debris, and are unsuppressed by nonrelativistic velocities in the debris. We find that these exchanges can be resummed using operator methods, and cancel at the level of the cross section until at least $O({\alpha }^3)$. Furthermore, we argue that both final and initial state Coulomb exchanges (enhanced by the number of electrons in the atom) do not affect the cross section until at least $O({\alpha }^3)$. Transverse photon couplings to nonrelativistic electrons are proportional to their small velocities, and rotational invariance suppresses their contribution to $O({\alpha }^3)$. Our results are relevant for precision experiments involving neutrinos, electrons, positrons, and muons scattering off of atomic electrons in a fixed target.

While the entanglement entropy of a single subregion in quantum field theory is formally infinite and requires regularization, certain combinations of entropies are perfectly finite in the limit that the regulator is removed, the mutual information being a common example. For generic regulator schemes, such as a holographic calculation with a uniform radial cutoff, these quantities show nontrivial dependence on the regulator at finite values of the cutoff. We investigate a holographic regularization scheme defined in three-dimensional anti-de Sitter space constructed from horocycles, curves in two-dimensional hyperbolic space perpendicular to all geodesics approaching a single point on the boundary, that leads to finite information measures that are totally cutoff independent, even at finite values of the regulator. We describe a broad class of such information measures, and describe how the field theory dual to the horocycle regulator is inherently nonlocal.

More than a decade ago, the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope unveiled the existence of two gigantic gamma-ray lobes known as the Fermi bubbles. While their origin is still unknown, various studies identified intricate spectral and morphological structures within the bubbles. One peculiar region, the cocoon, has recently been associated with gamma-ray emissions from the Sagittarius dwarf spheroidal (Sgr) galaxy. We assess the validity of this claim through adaptive-template fitting and pixel-count statistical methods. Our approach introduces a substantial advancement in data interpretation by enabling a data-driven optimization of astrophysical background models, thereby reducing the impact of background mismodeling. We do not find evidence for gamma-ray emission from the Sgr region at the level obtained in previous work. We demonstrate that there is no pronounced difference between the source population located within the cocoon region and a reference region at similar latitudes. We examine the hypothesis that a millisecond pulsar population in Sgr causes the putative signal via dedicated simulations finding that it is unlikely that we may have detected their presence in Sgr.

The discovery of XYZ exotic states in the hadronic sector with two heavy quarks represents a significant challenge in particle theory. Understanding and predicting their nature remains an open problem. In this work, we demonstrate how the Born-Oppenheimer (BO) effective field theory (BOEFT), derived from quantum chromodynamics (QCD) on the basis of scale separation and symmetries, can address XYZ exotics of any composition. We derive the Schrödinger coupled equations that describe hybrids, tetraquarks, pentaquarks, doubly heavy baryons, and quarkonia at leading order, incorporating nonadiabatic terms, and present the predicted multiplets. We define the static potentials in terms of the QCD static energies for all relevant cases. We provide the precise form of the nonperturbative low-energy gauge-invariant correlators required for the BOEFT: static energies, generalized Wilson loops, gluelumps, and adjoint mesons. These are to be calculated on the lattice, and we calculate here their short-distance behavior. Furthermore, we outline how spin-dependent corrections and mixing terms can be incorporated using matching computations. Lastly, we discuss how static energies with the same BO quantum numbers mix at large distances leading to the phenomenon of avoided level crossing. This effect is crucial to understand the emergence of exotics with molecular characteristics, such as the ${\chi }_{c1}(3872)$. With BOEFT both the tetraquark and the molecular picture appear as part of the same description.

The formation redshift and abundance of the first stars and galaxies is highly sensitive to the build up of low-mass dark matter halos as well as astrophysical feedback effects which modulate star formation in these low-mass halos. The 21 cm signal at cosmic dawn will depend strongly on the formation of these first luminous sources and thus can be used to constrain unknown astrophysical and dark matter properties in the early Universe. In this paper, we explore how well we could measure properties of dark matter using the 21 cm power spectrum at $z>10$, given unconstrained astrophysical parameters. We create a generalizable form of the dark matter halo mass function for models with damped and/or oscillatory linear power spectra, finding a single ‘smooth-$k$’ window function which describes a broad range of models including CDM. We use this to make forecasts for structure formation using the effective theory of structure formation (ETHOS) framework to explore a broad parameter space of dark matter models. We make predictions for the 21 cm power spectrum observed by HERA varying both cosmological ETHOS parameters as well as astrophysical parameters. Using a Markov chain Monte Carlo forecast we find that the ETHOS dark matter parameters are degenerate with astrophysical parameters linked to star formation in low-mass dark matter halos but not with x-ray heating produced by the first generation of stars. After marginalizing over uncertainties in astrophysical parameters we demonstrate that with just 540 days of HERA observations it should be possible to distinguish between CDM and a broad range of dark matter models with suppression at wave numbers $k\lesssim 200h{\mathrm{Mpc}}^{-1}$ assuming a moderate noise level. These results demonstrate the potential of 21 cm observations to constrain the matter power spectrum on scales smaller than current probes.

Recent studies have claimed that the strong $CP$ problem does not occur in QCD, proposing a new order of limits in volume and topological sectors when studying observables on the lattice. In order to shed light on this issue, we study the effect of the topological $\theta$-term on a simple quantum mechanical rotor that allows a lattice description. The topological susceptibility and the $\theta$-dependence of the energy spectrum are both computed using local lattice correlation functions. The sign problem is overcome by considering Taylor expansions in $\theta$, exploiting automatic differentiation methods for Monte Carlo processes. Our findings confirm the conventional wisdom on the strong $CP$ problem.