This study presents a thorough comparative analysis between post-Newtonian (PN) and numerically relativistic (NR) waveforms in eccentric orbits, covering nonspinning and spin-aligned configurations. The comparison examines frequency, amplitude, and phase characteristics of various harmonic modes, including $(\ell ,m)=(2,2),(2,1),(3,3),(3,2),(4,4),(5,5)$ modes. The study utilizes eccentric PN waveforms based on 3PN quasi-Keplerian parametrization with 3PN radiative reaction, surpassing Newtonian quadrupole moment with higher-order moments. NR waveforms from RIT and SXS catalogs span mass ratios from $1/4$ to 1, eccentricities up to 0.45, and durations exceeding $17000M$ across nonspinning and spin-aligned configurations. Focusing on the (2, 2) mode, frequency comparisons between quadrupole and higher-order moments of ${\mathrm{\Psi }}_4^{22}$ and $h^{22}$ were conducted. Amplitude comparisons revealed superior accuracy in quadrupole moments of ${\mathrm{\Psi }}_4^{22}$. Analysis of total 180 sets of eccentric waveforms showed increasing fitting residuals with rising eccentricity, correlating with smaller mass ratios. Comparisons of initial eccentricity from PN fitting, 3PN quasi-Keplerian parametrization, and RIT/SXS catalogs revealed alignment discrepancies. Frequency, phase, and amplitude comparisons of (2, 2) modes show consistent inspiral behavior between PN and NR, with divergences near merger for nonspinning PN and pre-$200M$ for spin-aligned PN. Average errors of frequency, phase, and amplitude up to $200M$ premerger amplify with increasing eccentricity. Average errors for eccentricities of 0–0.2 are below 3% for frequency, 0.2 for phase, and 6% for amplitude. For eccentricities of 0.2–0.4, errors increase. The higher-order modes demonstrate consistent trends for frequency and phase, and with increased amplitude errors, underscoring the self-consistency of the PN fitting process. Fittings on three RIT eccentric waveforms with low mass ratios highlight deviation between PN and NR for such scenarios. Refinements in PN and NR accuracy, especially at higher orders, and small mass ratios are essential for precise gravitational wave templates in eccentric orbits, reducing systematic errors in parameter estimation and advancing gravitational wave detection.

Although the standard $\mathrm{\Lambda }+\mathrm{cold}$ dark matter ($\mathrm{\Lambda }\mathrm{CDM}$) model is well tested on large scales, the primordial power spectrum may deviate from the $\mathrm{\Lambda }\mathrm{CDM}$ spectrum on small scales due to specific dark matter properties or alternative inflationary models. These deviations affect the formation of dark matter structure, which subsequently leads to different observable properties of galaxies. In this work, we study the impact of a blue and red tilted power spectrum on the central density of dwarf galaxies. To do this, we model densities of dwarf galaxies using a combination of high-resolution numerical simulations and galaxy formation model. The model galaxies in $\mathrm{\Lambda }\mathrm{CDM}$ are consistent with observations of 41 faint dwarf satellite galaxies of the Milky Way. The deviations from the $\mathrm{\Lambda }\mathrm{CDM}$ power spectrum are constrained by the central matter densities of dwarf galaxies, which set stringent constraints on the possible small-scale tilt of the primordial power spectrum, improving on the current limits. Moreover, similar analysis can be applied to test any feature in the power spectrum at small scales between $k\sim 10–100{\mathrm{Mpc}}^{-1}$.

As one of the fundamental unknowns of our Universe, the mass of dark matter remains to be a topic of great interest. We consider the possibility of a time-variation of the dark matter mass. We study the cosmological constraints on a model where the dark matter mass transitions from zero to a finite value in the early Universe. In this model, the matter power spectrum exhibits power suppression below a certain scale that depends on the epoch of transition, and the angular power spectrum of the cosmic microwave background shows a distinctive phase shift and power suppression at small scales. We use the latest cosmic microwave background data and the $S_8$ priors from weak lensing data to place a lower limit on the transition redshift. We also find that the data from the Atacama Cosmology Telescope (ACT) show a mild preference for the mass-varying dark matter model over $\mathrm{\Lambda }$ Cold Dark Matter ($\mathrm{\Lambda }\mathrm{CDM}$).

We analyze the power spectrum and the bispectrum of BOSS galaxy-clustering data using the prediction from the effective field theory of large-scale structure at one-loop order for both the power spectrum and the bispectrum. With $\mathrm{\Lambda }\mathrm{CDM}$ parameters fixed to Planck preferred values, we set limits on three templates of non-Gaussianities predicted by many inflationary models: the equilateral, the orthogonal, and the local shapes. After validating our analysis against simulations, we find $f_{\mathrm{NL}}^{\mathrm{equil}}=207\pm 292$, $f_{\mathrm{NL}}^{\mathrm{orth}}=-68\pm 73$, $f_{\mathrm{NL}}^{\mathrm{loc}}=52\pm 34$, at 68% confidence level. These bispectrum-based constraints from large-scale structure, not far from the ones of WMAP, suggest promising results from upcoming surveys.

Gravitational waves (GWs) from the inspiral of binary compact objects offer a one-step measurement of the luminosity distance to the event, which is essential for the measurement of the Hubble constant, $H_0$, which characterizes the expansion rate of the Universe. However, unlike binary neutron stars, the inspiral of binary black holes is not expected to be accompanied by electromagnetic radiation and a subsequent determination of its redshift. Consequently, independent redshift measurements of such GW events are necessary to measure $H_0$. In this study, we present a novel Bayesian approach to infer $H_0$ by measuring the overdensity of galaxies around individual binary black hole merger events in configuration space. We model the measured overdensity using the 3D cross-correlation between galaxies and GW events, explicitly accounting for the GW event localization uncertainty. We demonstrate the efficacy of our method with 250 simulated GW events distributed within 1 Gpc in colored Gaussian noise of Advanced LIGO and Advanced Virgo detectors operating at O4 sensitivity. We show that such measurements can constrain the Hubble constant with a precision of $\lesssim 8\%$ (90% highest density interval). We highlight the potential improvements that need to be accounted for in further studies before the method can be applied to real data.

We estimate collapse rates of axion stars in our galaxy based on the axion minicluster mass function of the Milky Way dark matter halo. We consider axionlike particles (ALP) with different temperature evolution of the axion mass, including the QCD axion with $m_a=50\mathrm{\mu }\mathrm{eV}$. Combining estimates for the present-day axion star mass function from our previous work with the axion star accretion model predicted by self-similar growth, we can infer the expected number of bosenovae occurring within the Milky Way. Our estimates suggest that for an observation time of $t_{\mathrm{obs}}=1\mathrm{yr}$, the majority of the up to $\sim {10}^{13}$ bosenovae per galaxy occur in the densest miniclusters with initial overdensity parameter $\mathrm{\Phi }\lesssim {10}^4$. We discuss the detectability of such recurring axion bursts within our galactic vicinity and find that, for models with derivative couplings including axion-fermion interactions, potential broadband axion dark matter experiments can probe a large range of ALP masses $m_a\lesssim {10}^{-6}\mathrm{eV}$ and with moderate improvements even the quantum chromodynamics axion case. For axions with nonderivative-type interactions like the axion-photon coupling, our analysis suggests that optimistic predictions with order-one dark matter abundance of axion stars $f_{\star }\sim 1$ can be probed by dedicated burst searches.

Energetic cosmic rays scatter off the cosmic neutrino background throughout the history of the Universe, yielding a diffuse flux of cosmic relic neutrinos boosted to high energies. We calculate this flux under different assumptions of the cosmic-ray flux spectral slope and redshift evolution. The nonobservation of the diffuse flux of boosted relic neutrinos with current high-energy neutrino experiments already excludes an average cosmic neutrino background overdensity larger than $\sim {10}^4$ over cosmological distances. We discuss the future detectability of the diffuse flux of boosted relic neutrinos in light of neutrino overdensity estimates and cosmogenic neutrino backgrounds.

The $SU(2{)}_L\times U(1{)}_Y$ invariance of the Standard Model effective field theory (SMEFT) predicts multiple restrictions in the space of Wilson coefficients of $U(1{)}_{em}$ invariant effective Lagrangians such as the low-energy effective field theory (LEFT), used for low-energy flavor physics observables, or the Higgs effective field theory (HEFT) in unitary gauge, appropriate for weak-scale observables. In this work, we derive and list all such predictions for semileptonic operators up to dimension 6. These predictions can be expressed as linear relations among the HEFT/LEFT Wilson coefficients (WCs), that are completely independent of any assumptions about the alignment of the mass and flavor bases. We find seven sets of relations among the WCs of vector operators, nine sets with scalar and tensor operators, and two sets with the $Z,W^{\pm }$ couplings. These correspond to 2223 linear relations among the complex WCs when the quark and lepton generation indices are included. They connect diverse experimental searches such as rare meson decays, high-$p_T$ dilepton searches, top decays, $Z$-pole observables, charged lepton flavor violating observables, and nonstandard neutrino interaction searches. We demonstrate how these relations can be used to derive strong indirect constraints on multiple WCs that are currently either weakly constrained from direct experiments or have no direct bound at all. They also imply, in general, that evidence for new physics in a particular search channel must be accompanied by correlated anomalies in other channels. For example, the observed excess in $B\to K\nu \overline{\nu }$ would imply possible anomalies in $B\to D^{(*)}\ell {\nu }_{\ell }$, $B\to K^{(*)}{\ell }^{+}{\ell }^{-}$, $B_q\to \tau {\nu }_{\tau }$, $B_s\to {\tau }^{+}{\tau }^{-}$, $D_s\to {\tau }^{+}{\nu }_{\tau }$, $t\to c{\ell }^{+}{\ell }^{-}$, $t\to u{\ell }^{+}{\ell }^{-}$, etc., correlated according to the relations obtained in this paper.

It is well known that there are persistent statistical tensions with the standard model in the low ${\mathrm{Q}}^2$ HERA deep inelastic scattering neutral current data characterized by a turnover of the neutral current reduced cross section at low x and low ${\mathrm{Q}}^2$. One important experimental signature that sheds light on this low ${\mathrm{Q}}^2$ region is the determination of the longitudinal structure function ${\mathrm{F}}_{\mathrm{L}}(\mathrm{x},{\mathrm{Q}}^2)$. This paper describes a novel method to determine ${\mathrm{F}}_{\mathrm{L}}$ based on an extrapolation of the reduced neutral current cross section at fixed $\surd s$ and ${\mathrm{Q}}^2$ to the minimum value of x given by ${\mathrm{Q}}^2/\mathrm{s}$. At this kinematic point, the reduced cross section equals $2{\mathrm{xF}}_1={\mathrm{F}}_2{\text{−}\mathrm{F}}_{\mathrm{L}}$ so that a determination of both this value and the value of ${\mathrm{F}}_2$, determines ${\mathrm{F}}_{\mathrm{L}}$. Since the polarization of the exchanged photon is transverse at this kinematic point, we expect ${\mathrm{F}}_{\mathrm{L}}$ to be small because its dominant gluon component is strongly suppressed. Surprisingly, we find ${\mathrm{F}}_{\mathrm{L}}$ at low ${\mathrm{Q}}^2$ to be much larger than expectation and observe that both ${\mathrm{F}}_{\mathrm{L}}$ and ${\mathrm{F}}_2$ at $\mathrm{x}={\mathrm{Q}}^2/\mathrm{s}$ show several properties consistent with the dipole picture. We discuss the statistical as well as chief systematic uncertainties of our method and we tabulate our determinations of ${\mathrm{F}}_2$, $2{\mathrm{xF}}_1$, and ${\mathrm{F}}_{\mathrm{L}}$ in an Appendix.

The issue of consistency is crucial in quantum gravity. It has recently been intensively addressed for effective symmetry-reduced models. In this article, we exhaustively study the anomaly freedom of effective loop quantum cosmology with generalized holonomy corrections, considering loop correction of the constraints at the perturbative order. We pedagogically explain why, although the holonomy correction—including the details of the chosen scheme—applied on the background part of the constraints is crucial, it becomes irrelevant when implemented on perturbative expansions, in the sense that all consequences are “absorbed” in the counter-terms used for the regularization. The corrected terms do not appear in the Hamiltonian of the perturbations. The possibility of closing the algebra of constraints without counter-terms is also studied. It is argued that, although enforcing a first-class algebra is a strong requirement, this can be achieved in several different ways, often overlooked, which generates ambiguities on the restriction of the form of the generalized holonomy correction. Those ambiguities are examined in detail, leading to the conclusion that the consistency of the effective theory for cosmological perturbations, especially when considering scalar modes, cannot be achieved without counter-terms. We also take the opportunity in this work to clarify, as much as possible, all the required steps so that future works have a clear material at disposal. In particular, a highly detailed calculation of all the brackets is provided, emphasizing the (usually implicit) assumptions, hypotheses, and manipulations required to ensure the closure of the algebra. Prospects for future works are underlined.

In this paper, we present a second realization of the Weyl double copy (WDC) in four-dimensional algebraic type D spacetime. We show that any type D vacuum solution admits an algebraically general Maxwell scalar on the curved background that squares to give the Weyl scalar. The WDC relation defines a scalar field that satisfies the Klein-Gordon equation sourced by the Weyl scalar on the curved background. We then extend the type D WDC to five dimensions.

We study high-energy scattering at fixed angle in the planar limit of non-Abelian gauge field theories from type IIB superstring theory scattering amplitudes. First, we consider four-glueball scattering described in terms of the four-dilaton string theory scattering amplitude. We explicitly calculate some angular integrals of four scalar spherical harmonics on the five sphere leading to selection rules for several scattering processes. Then, we consider the high-energy limit of the four-dilatino scattering amplitude in type IIB superstring theory, which allows to describe four spin-$1/2$ fermions scattering in the dual gauge field theory. In both cases, the partonic structure of the scattering cross sections is obtained. The Regge behavior is also obtained. In addition, we study certain related aspects by considering the effective action constructed from IIB supergravity.

The backreaction of quantum degrees of freedom on classical backgrounds is a poorly understood topic in theoretical physics. Most often it is treated within the semiclassical approximation with the help of various ad hoc prescriptions accounting for the effect of quantum excitations on the dynamics of the background. We focus on two popular ones: (i) the mean-field approximation whereby quantum degrees of freedom couple to the classical background via their quantum expectation values; (ii) the (stochastic) truncated Wigner method whereby the fully coupled system is evolved using classical equations of motion for various randomly sampled initial conditions of the quantum degree of freedom, and a statistical average is performed a posteriori. We evaluate the performance of each method in a simple toy model against a fully quantum mechanical treatment, and identify its regime of validity. We interpret the results in terms of quantum entanglement and loss of classicality of the background.

Quasinormal modes are excited during the ringdown phase of black holes after merger. Determination of quasinormal modes of rapidly rotating black holes in alternative theories of gravity has remained a challenge for a long time. Here we discuss in detail our recently developed method to extract the quasinormal modes for rapidly rotating black holes in Einstein-Gauss-Bonnet-dilaton theory. We first obtain numerically the exact rapidly rotating background solutions, which also clarify their domain of existence. Then we solve the equations for the linear perturbations of the metric and the dilaton field by employing an appropriate set of boundary conditions and a spectral decomposition of the perturbation functions. The resulting spectrum agrees well with the known limits obtained for slow rotation and weak coupling, while it exhibits larger deviations for stronger coupling.

A new exact magnetized solution describing a Kiselev black hole immersed in a magnetic field is used for studying the dynamics of charged particles. Different types of trajectories are discussed. In the particular case of a weak magnetic field, we employ a first-order perturbative approach to analyze the perturbed circular orbits near the minimum of the effective potential. We obtain an approximate solution for the bounded equatorial trajectory subjected to small radial and latitudinal oscillations. The shape of the trajectory localized near the stable circular orbit depends on the relation between the attractive gravitational force and the repulsive quintessence contribution.

Accurately determining neutrino masses is a main objective of contemporary cosmology. Since massive neutrinos affect structure formation and evolution, probes of large scale structure are sensitive to the sum of their masses. In this work, we explore future constraints on $\sum m_{\nu }$ utilizing line-intensity mapping (LIM) as a promising emerging probe of the density of our Universe, focusing on the fine-structure [CII] line as an example, and compare these constraints with those derived from traditional galaxy surveys. Additionally, we perform a multitracer analysis using velocity tomography via the kinetic Sunyaev-Zeldovich and moving lens effects to reconstruct the three-dimensional velocity field. Our forecasts indicate that the next-generation AtLAST detector by itself can achieve ${\sigma }_{\mathrm{\Sigma }{m}_{\nu }}\sim 50\mathrm{meV}$ sensitivity. Velocity tomography will further improve these constraints by 4%. Incorporating forecasts for CMB-S4 and DESI-BAO in a comprehensive multitracer analysis, while setting a prior on the optical depth to reionization $\tau$ derived using 21-cm forecasted observations, to break degeneracies, we find that a $\gtrsim 5\sigma$ detection of $\sum m_{\nu }\sim 60\mathrm{meV}$, under the normal hierarchy, is within reach with LIM. Even without a $\tau$ prior, our combined forecast reaches ${\sigma }_{\mathrm{\Sigma }{m}_{\nu }}\sim 18\mathrm{meV}$.

We study the formation of solitons inside scalar-field dark matter halos with a nonpolynomial self-interaction potential. We consider a self-interaction potential that is quartic in the scalar field in the low-density regime but saturates at large densities. This mimics the behavior of axion monodromy potentials. We concentrate on the semiclassical regime, where the de Broglie wavelength is much smaller than the size of the system. We find that depending on the strength and scale of the self-interactions, the system can form solitons of the Thomas-Fermi type (dominated by self-interactions) or of the fuzzy dark matter type (dominated by the quantum pressure). The system can also display transitions from a Thomas-Fermi soliton to a fuzzy dark matter soliton as the former becomes unstable. We show that these behaviors can be understood from a simple Gaussian ansatz. We find that even in cases where the self-interactions are always subdominant they can play a critical role, by providing a small density boost that is enough to generate the seed for the formation of a fuzzy dark matter soliton at much later times. We also point out that the intuition derived from a hydrodynamical picture can be misleading in regimes where wave effects are important.

Massive particles leave imprints on primordial non-Gaussianity via couplings to the inflaton, even despite their exponential dilution during inflation: practically, the Universe acts as a cosmological collider. We present the first dedicated search for spin-zero particles using BOSS redshift-space galaxy power spectrum and bispectrum multipoles, as well as Planck CMB non-Gaussianity data. We demonstrate that some cosmological collider models are well approximated by the standard equilateral and orthogonal parametrization; assuming negligible inflaton self-interactions, this facilitates us translating Planck non-Gaussianity constraints into bounds on collider models. Many models have signatures that are not degenerate with equilateral and orthogonal non-Gaussianity and thus require dedicated searches. Here, we constrain such models using BOSS three-dimensional redshift-space galaxy clustering data, focusing on spin-zero particles in the principal series (i.e., with mass $m\ge 3H/2$) and constraining their couplings to the inflaton at varying speed and mass, marginalizing over the unknown inflaton self-interactions. This is made possible through the combination of perturbation theory and halo occupation distribution models for galaxy clustering. Together with the CMB analaysis of Sohn et al. [J. Cosmol. Astropart. Phys. 09 (2024) 016], our work sets the standard for inflationary spectroscopy with cosmological observations, providing the ultimate link between physics on the largest and smallest scales.