The 100 most-cited articles in Physical review. D/Physical review. D., 2023

This paper reports world averages of measurements of b-hadron, c-hadron, and τ-lepton properties obtained by the Heavy Flavor Averaging Group using results available before April 2021.In rare cases, significant results obtained several months later are also used.For the averaging, common input parameters

A new analysis of the distribution of matter in the Universe continues to find a discrepancy in the clumpiness of dark matter in the late and early Universe, suggesting a fundamental error in the standard cosmological model.

We present a lattice determination of the leading-order hadronic vacuum polarization (HVP) contribution to the muon anomalous magnetic moment, ${a}_{\ensuremath{\mu}}^{\mathrm{HVP}}$, in the so-called short and intermediate time-distance windows, ${a}_{\ensuremath{\mu}}^{\mathrm{SD}}$ and ${a}_{\ensuremath{\mu}}^{\mathrm{W}}$, defined by the RBC/UKQCD Collaboration [Phys. Rev. Lett. 121, 022003 (2018)]. We employ gauge ensembles produced by the Extended Twisted Mass Collaboration (ETMC) with ${N}_{f}=2+1+1$ flavors of Wilson-clover twisted-mass quarks with masses of all the dynamical quark flavors tuned close to their physical values. The simulations are carried out at three values of the lattice spacing equal to $\ensuremath{\simeq}0.057$, 0.068 and 0.080 fm with spatial lattice sizes up to $L\ensuremath{\simeq}7.6\text{ }\text{ }\mathrm{fm}$. For the short-distance window we obtain ${a}_{\ensuremath{\mu}}^{\mathrm{SD}}(\mathrm{ETMC})=69.27(34)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}$, which is consistent with the recent dispersive value of…

Spin precession is one of the key physical effects that coul unveil the origin of the compact binaries detected by ground- and space-based gravitational-wave (GW) detectors, and shed light on their possible formation channels. Efficiently and accurately modeling the GW signals emitted by these systems is crucial to extract their properties. Here, we present SEOBNRv5PHM, a multipolar precessing-spin waveform model within the effective-one-body formalism for the full signal (i.e. inspiral, merger and ringdown) of binary black holes (BBHs). In the nonprecessing limit, the model reduces to SEOBNRv5HM, which is calibrated to 442 numerical-relativity (NR) simulations, 13 waveforms from BH perturbation theory, and nonspinning energy flux from second-order gravitational self-force theory. We remark that SEOBNRv5PHM is not calibrated to precessing-spin NR waveforms from the Simulating eXtreme Spacetimes Collaboration. We validate SEOBNRv5PHM by computing the unfaithfulness against 1543 precessing-spin NR waveforms, and find that for 99.8% (84.4%) of the cases, the maximum value, in the total…

Formulating a precise notion of holography between gravity in asymptotically flat spacetime and a lower-dimensional field theory remains an outstanding problem. In this paper, the authors discuss two seemingly disparate existing approaches to such a duality, namely the celestial and Carrolian holography, and show that they are connected by an integral transform.

We present SEOBNRv5HM, a more accurate and faster inspiral-merger-ringdown gravitational waveform model for quasicircular, spinning, nonprecessing binary black holes within the effective-one-body (EOB) formalism. Compared to its predecessor, SEOBNRv4HM, the waveform model (i) incorporates recent high-order post-Newtonian results in the inspiral, with improved resummations, (ii) includes the gravitational modes $(\ensuremath{\ell},|m|)=(3,2),(4,3)$, in addition to the (2,2), (3,3), (2,1), (4,4), (5,5) modes already implemented in SEOBNRv4HM, (iii) is calibrated to larger mass ratios and spins using a catalog of 442 numerical-relativity (NR) simulations and 13 additional waveforms from black-hole perturbation theory, and (iv) incorporates information from second-order gravitational self-force in the nonspinning modes and radiation-reaction force. Computing the unfaithfulness against NR simulations, we find that for the dominant (2,2) mode the maximum unfaithfulness in the total mass range $10--300{M}_{\ensuremath{\bigodot}}$ is below ${10}^{\ensuremath{-}3}$ for 90% of the cases (38%…

We present a sample-variance-limited measurement of the temperature power spectrum ($TT$) of the cosmic microwave background using observations of a $\ensuremath{\sim}1500\text{ }\text{ }{\mathrm{deg}}^{2}$ field made by the SPT-3G in 2018. We report multifrequency power spectrum measurements at 95, 150, and 220 GHz covering the angular multipole range $750\ensuremath{\le}\ensuremath{\ell}<3000$. We combine this $TT$ measurement with the published polarization power spectrum measurements from the 2018 observing season and update their associated covariance matrix to complete the SPT-3G 2018 $TT/TE/EE$ dataset. This is the first analysis to present cosmological constraints from SPT $TT$, $TE$, and $EE$ power spectrum measurements jointly. We blind the cosmological results and subject the dataset to a series of consistency tests at the power spectrum and parameter level. We find excellent agreement between frequencies and spectrum types and our results are robust to the modeling of astrophysical foregrounds. We report results for $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ and a…

A new analysis of the distribution of matter in the Universe continues to find a discrepancy in the clumpiness of dark matter in the late and early Universe, suggesting a fundamental error in the standard cosmological model.

Black hole spectroscopy is the program to measure the complex gravitational wave frequencies of merger remnants, and to quantify their agreement with the characteristic frequencies of black holes computed at linear order in black hole perturbation theory. In a ``weaker'' (nonagnostic) version of this test, one assumes that the frequencies depend on the mass and spin of the final Kerr black hole as predicted in perturbation theory. Linear perturbation theory is expected to be a good approximation only at late times, when the remnant is close enough to a stationary Kerr black hole. However, it has been claimed that a superposition of overtones with frequencies fixed at their asymptotic values in linear perturbation theory can reproduce the waveform strain even at the peak. Is this overfitting, or are the overtones physically present in the signal? To answer this question, we fit toy models of increasing complexity, waveforms produced within linear perturbation theory, and full numerical relativity waveforms using both agnostic and nonagnostic ringdown models. We find that higher…

We introduce caloflow, a fast detector simulation framework based on normalizing flows. For the first time, we demonstrate that normalizing flows can reproduce many-channel calorimeter showers with extremely high fidelity, providing a fresh alternative to computationally expensive geant4 simulations, as well as other state-of-the-art fast simulation frameworks based on generative adversarial networks (GANs) or variational autoencoders (VAEs). In addition to the usual histograms of physical features and images of calorimeter showers, we introduce a new metric for judging the quality of generative modeling: the performance of a classifier trained to differentiate real from generated images. We show that GAN-generated images can be identified by the classifier with nearly 100% accuracy, while images generated from caloflow are better able to fool the classifier. More broadly, normalizing flows offer several advantages compared to other state-of-the-art approaches (GANs and VAEs), including tractable likelihoods, stable and convergent training, and principled model selection.…

The authors use Dark Energy Survey data on galaxy clustering and lensing from the first three years of observations combined with five prominent external datasets. They robustly constrain six potential extensions to the currently prevalent cosmological paradigm of \ensuremath{\Lambda}CDM (Cold Dark Matter with a cosmological constant). All extensions would add significant new physics, such as deviations from General Relativity or non-zero spatial curvature, but no significant evidence for new physics is found.

In this paper, we extend our previous work [D. Wu, Phys. Rev. D 107, 024024 (2023)] to the more general cases with a negative cosmological constant, and investigate the topological numbers for the singly rotating Kerr-AdS black holes in all dimensions and the four-dimensional Kerr-Newman-AdS black hole as well as the three-dimensional Ba\~nados-Teitelboim-Zanelli black hole. We find that the topological numbers of black holes are remarkably influenced by the cosmological constant. In addition, we also demonstrate that the dimension of spacetimes has an important effect on the topological number for rotating anti--de Sitter (AdS) black holes. Furthermore, it is interesting to observe that the difference between the topological number of the AdS black hole and that of its corresponding asymptotically flat black hole is always unity. This new observation leads us to conjure that it might be valid also for other black holes. Of course, this novel conjecture needs to be further verified by examining the topological numbers of many other black holes and their AdS counterparts in the…

The novel data analysis challenges posed by the Laser Interferometer Space Antenna (LISA) arise from the overwhelmingly large number of astrophysical sources in the measurement band and the density with which they are found in the data. Robust detection and characterization of the numerous gravitational wave sources in LISA data can not be done sequentially, but rather through a simultaneous global fit of a data model containing the full suite of astrophysical and instrumental features present in the data. While previous analyses have focused on individual source types in isolation, here we present the first demonstration of a LISA global fit analysis containing combined astrophysical populations. The prototype pipeline uses a blocked Metropolis Hastings algorithm to alternatingly fit to a population of ultra compact galactic binaries, known ``verification binaries'' already identified by electromagnetic observations, a population of massive black hole mergers, and an instrument noise model. The Global LISA Analysis Software Suite (GLASS) is assembled from independently developed…

The authors develop a formalism for computing the abundance of primordial black holes (PBH) in the presence of local non-Gaussianities in the curvature perturbation field. They show that polynomial expansions will not suffice in certain limits and provide numerical methods to address this issue. They demonstrate how their technique affects both the total PBH abundances and gravitational wave expectations.

Motivated by the fact that cosmological models based on $f(Q)$ gravity are very efficient in fitting observational datasets at both background and perturbation levels, we perform a combined dynamical system analysis of both background and perturbation equations in order to examine the validity of this result through an independent method. We examine two studied $f(Q)$ models of the literature, namely, the power-law and the exponential ones. For both cases, we obtain a matter-dominated saddle point characterized by the correct growth rate of matter perturbations, followed by the transition to a stable dark-energy-dominated accelerated universe in which matter perturbations remain constant. Furthermore, analyzing the behavior of $f{\ensuremath{\sigma}}_{8}$, we find that the models fit observational data successfully, obtaining a behavior similar to that of the Lambda cold dark matter ($\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$) scenario, although the exponential model does not possess the latter as a particular limit. Hence, through the independent approach of dynamical systems, we…

A simultaneous analysis of the B þ → K þ l þ l -and B 0 → K Ã0 l þ l -decays is performed to test muonelectron universality in two ranges of the square of the dilepton invariant mass, q 2 .The measurement uses a sample of beauty meson decays produced in proton-proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 fb -1 .A sequence of multivariate selections and strict particle identification requirements produce a higher signal purity and a better statistical sensitivity per unit luminosity than previous LHCb lepton universality tests using the same decay modes.Residual backgrounds due to misidentified hadronic decays are studied using data and included in the fit model.Each of the four lepton universality measurements reported is either the first in the given q 2 interval or supersedes previous LHCb measurements.The results are compatible with the predictions of the Standard Model.

The LHCb Collaboration has recently released a new study of ${B}^{+}\ensuremath{\rightarrow}{K}^{+}{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ and $B\ensuremath{\rightarrow}{K}^{*0}{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ ($\ensuremath{\ell}=e$, $\ensuremath{\mu}$) decays, testing lepton universality with unprecedented accuracy using the whole Run 1 and 2 dataset. In addition, the CMS Collaboration has reported an improved analysis of the branching ratios ${B}_{(d,s)}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$. While these measurements offer, per se, a powerful probe of new physics, global analyses of $b\ensuremath{\rightarrow}s{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ transitions also rely on the assumptions about nonperturbative contributions to the decay matrix elements. In this work, we perform a global Bayesian analysis of new physics in (semi)leptonic rare $B$ decays, paying attention to the role of charming penguins which are difficult to evaluate from first principles. We find data…

We report on the search for dark matter weakly interacting massive particles (WIMPs) in the mass range below $10\text{ }\text{ }\mathrm{GeV}/{\mathrm{c}}^{2}$, from the analysis of the entire dataset acquired with a low-radioactivity argon target by the DarkSide-50 experiment at Laboratori Nazionali del Gran Sasso. The new analysis benefits from more accurate calibration of the detector response, improved background model, and better determination of systematic uncertainties, allowing us to accurately model the background rate and spectra down to $0.06\text{ }\text{ }{\mathrm{keV}}_{er}$. A 90% C.L. exclusion limit for the spin-independent cross section of $3\text{ }\text{ }\mathrm{GeV}/{\mathrm{c}}^{2}$ mass WIMP on nucleons is set at $6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}43}\text{ }\text{ }{\mathrm{cm}}^{2}$, about a factor 10 better than the previous DarkSide-50 limit. This analysis extends the exclusion region for spin-independent dark matter interactions below the current experimental constraints in the [1.2, 3.6] $\mathrm{GeV}/{\mathrm{c}}^{2}$ WIMP mass…

In this work, we present a convenient method to perform the topological analysis of black hole thermodynamics. Utilizing the spinodal curve, thermodynamic critical points of a black hole are endowed with a topological quantity, Brouwer degree, which reflects intrinsic properties of the system under smooth deformations. Particularly, in our setup it can be easily calculated without an exact solution of critical points. This enables us to conveniently investigate the topological transition between different thermodynamic systems, and give a topological classification for them. In this framework, topology of Lovelock AdS black holes with spherical horizon geometry is explored. Results show that charged black holes in arbitrary dimensions can be classified into the same topology class, whereas the $d=7$ and $d\ensuremath{\ge}8$ uncharged black holes are in different topology classes. Moreover, we revisit the relation between different phase structures of these black holes from the viewpoint of topology. Some general topological properties of critical points are also discussed.

In this paper, we investigate the topological numbers for the singly rotating Kerr black holes in all dimensions and the four-dimensional Kerr-Newman black hole. We show that for uncharged black holes, the rotation parameter has a significant effect on the topological number, and for rotating black holes, the dimension of spacetimes has a remarkable effect on the topological number too. In addition, we find that the topological numbers of the four-dimensional Kerr and Kerr-Newman black holes are the same, which seems to indicate that the electric charge parameter has no effect on the topological number of rotating black holes. Our current research provides more evidence that the conjecture put forward in Wei et al. [Phys. Rev. Lett., 129, 191101 (2022)], according to which all black hole solutions should be separated into three different topological classes, is accurate, at least in the pure Einstein-Maxwell gravity theory.

We compute the standard Euclidean window of the hadronic vacuum polarization using multiple independent blinded analyses. We improve the continuum and infinite-volume extrapolations of the dominant quark-connected light-quark isospin-symmetric contribution and address additional subleading systematic effects from sea-charm quarks and residual chiral-symmetry breaking from first principles. We find ${a}_{\mathrm{\ensuremath{\mu}}}^{\mathrm{W}}=235.56(65)(50)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}$, which is in $3.8\ensuremath{\sigma}$ tension with the recently published dispersive result of ${a}_{\mathrm{\ensuremath{\mu}}}^{\mathrm{W}}=229.4(1.4)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}$ [G. Colangelo, A. X. El-Khadra, M. Hoferichter, A. Keshavarzi, C. Lehner, P. Stoffer, and T. Teubner, Phys. Lett. B 833, 137313 (2022)] and in agreement with other recent lattice determinations. We also provide a result for the standard short-distance window. The results reported here are unchanged compared to our presentation at the Edinburgh workshop of the g-2…

The Lorentz symmetry of gravity is spontaneously broken when the nonminimally coupled Kalb-Ramond field acquires a nonzero vacuum expectation value. In this work, we present exact solutions for static and spherically symmetric black holes in the framework of this Lorentz-violating gravity theory. In order to explore the physical implications of Lorentz violation, we analyze the thermodynamic properties of the obtained solutions and evaluate the impact of Lorentz violation on some classical gravitational experiments within the Solar System. Furthermore, the Lorentz-violating parameter is constrained by using the measured results of these experiments.

There is compelling evidence that the Universe is undergoing a late phase of accelerated expansion. One of the simplest explanations for this behavior is the presence of dark energy. A plethora of microphysical models for dark energy have been proposed. The hope is that, with the ever increasing precision of cosmological surveys, it will be possible to precisely pin down the model. We show that this is unlikely and that, at best, we will have a phenomenological description for the microphysics of dark energy. Furthermore, we argue that the current phenomenological prescriptions are ill-equipped for shedding light on the fundamental theory of dark energy.

In this work we consider the observational properties of compact boson stars with self-interactions orbited by isotropically emitting (hot-spot) sources and optically thin accretion disks. We consider two families of boson stars supported by quartic and sixth-order self-interaction potentials, and choose three samples of each of them in growing compactness; only those with large enough compactness are capable to hold light rings, namely, null bound orbits. For the hot spots, using inclination angles $\ensuremath{\theta}={20\ifmmode^\circ\else\textdegree\fi{},50\ifmmode^\circ\else\textdegree\fi{},80\ifmmode^\circ\else\textdegree\fi{}}$ we find a secondary track plunge-through image of photons crossing the interior of the boson star, which can be further decomposed into additional images if the star is compact enough. For accretion disks we find that the latter class of stars actually shows a sequence of additional secondary images in agreement with the hot-spot analysis, a feature absent in typical black hole space-times. Furthermore, we also find a shadowlike central brightness…

The forest of Lyman-$\ensuremath{\alpha}$ absorption lines detected in the spectra of distant quasars encodes information on the nature and properties of dark matter and the thermodynamics of diffuse baryonic material. Its main observable---the 1D flux power spectrum (FPS)---should exhibit a suppression on small scales and an enhancement on large scales in warm dark matter (WDM) cosmologies compared to standard $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$. Here, we present an unprecedented suite of 1080 high-resolution cosmological hydrodynamical simulations run with the graphics processing unit-accelerated code cholla to study the evolution of the Lyman-$\ensuremath{\alpha}$ forest under a wide range of physically motivated gas thermal histories along with different free-streaming lengths of WDM thermal relics in the early Universe. A statistical comparison of synthetic data with the forest FPS measured down to the smallest velocity scales ever probed at redshifts $4.0\ensuremath{\lesssim}z\ensuremath{\lesssim}5.2$ [E. Boera et al., Revealing reionization with the thermal history of…

The Bardeen black hole holds historical significance as the first model of a regular black hole. Recently, there have been proposed interpretations of the Bardeen spacetime as quantum corrections to the Schwarzschild solution. Our study focuses on investigating the quasinormal modes and Hawking radiation of the Bardeen black hole. We have observed that previous studies on the quasinormal modes for the Bardeen black hole suffer from inaccuracies that cannot be neglected. Therefore, we propose accurate calculations of the quasinormal modes for scalar, electromagnetic, and neutrino fields in the Bardeen spacetime. Additionally, we have computed the gray-body factors and analyzed the emission rates of Hawking radiation. Even when the quantum correction is small and the fundamental mode only slightly differs from its Schwarzschild value, the first several overtones deviate at an increasingly stronger rate. This deviation leads to the appearance of overtones with very small real oscillation frequencies. This outburst of overtones is closely linked to the fact that the quantum-corrected…

In a series of two papers, the authors explore the holographic duality between an eternal AdS black hole in the bulk and two copies of the boundary CFT in the thermal field double state. They provide an explicit construction in the boundary theory of an evolution operator for a bulk in-falling observer, thus making manifest the boundary emergence of the black hole horizons, the interiors, and the associated causal structure. They also elucidate that the emergence of the sharp bulk event horizon is related to the infinite N limit of the boundary theory.

We develop a numerical approach to find asymptotically flat black hole solutions coupled to anisotropic fluids, described by generic density profiles. Our model allows for a variety of applications in realistic astrophysical scenarios, and is potentially able to describe the geometry of galaxies hosting supermassive black holes, dark matter environments, and accretion phenomena. We apply our framework to a black hole surrounded by different families of dark matter profiles, namely the Hernquist, the Navarro-Frenk White, and the Einasto models. We study the geodesic motion of light and of massive particles in such spacetimes. Moreover we compute gravitational axial perturbations induced by a small secondary on the numerical background and determine the changes in the emitted gravitational wave fluxes compared to the vacuum case. Our analysis confirms and extends previous studies showing that modifications of orbital frequencies and axial fluxes can be described in terms of gravitational redshift, regardless of the halo model.

We present a detailed study on variational autoencoders (VAEs) for anomalous jet tagging at the Large Hadron Collider. By taking in low-level jet constituents' information and training with background QCD jets in an unsupervised manner, the VAE is able to encode important information for reconstructing jets, while learning an expressive posterior distribution in the latent space. When using the VAE as an anomaly detector, we present different approaches to detect anomalies: directly comparing in the input space or, instead, working in the latent space. A comprehensive series of test sets are generated to fully examine the anomalous tagging performance in different jet types. In order to facilitate general search approaches such as bump hunt, mass-decorrelated VAEs based on distance correlation regularization are also studied. We find that the naive mass-decorrelated VAEs fail at maintaining proper detection performance, by assigning higher probability to some anomalous samples. To build a performant mass-decorrelated anomalous jet tagger, we propose the outlier exposed VAE (OE-VAE),…

We analyze cosmic superstring models in light of NANOGrav 15-year pulsar timing data. A good fit is found for a string tension $G\ensuremath{\mu}\ensuremath{\sim}{10}^{\ensuremath{-}12}--{10}^{\ensuremath{-}11}$ and a string intercommutation probability $p\ensuremath{\sim}{10}^{\ensuremath{-}3}--{10}^{\ensuremath{-}1}$. Extrapolation to higher frequencies assuming standard big bang cosmology is compatible at the 68% CL with the current LIGO/Virgo/KAGRA upper limit on a stochastic gravitational wave background in the 10 to 100 Hz range. The superstring interpretation of the NANOGrav data would be robustly testable by future experiments even in modified cosmological scenarios.

A new analysis of the distribution of matter in the Universe continues to find a discrepancy in the clumpiness of dark matter in the late and early Universe, suggesting a fundamental error in the standard cosmological model.

Tools necessary for quantum simulations of $1+1$ dimensional quantum chromodynamics are developed. When formulated in axial gauge and with two flavors of quarks, this system requires 12 qubits per spatial site with the gauge fields included via nonlocal interactions. Classical computations and $D$-wave's quantum annealer advantage are used to determine the hadronic spectrum, enabling a decomposition of the masses and a study of quark entanglement. Color ``edge'' states confined within a screening length of the end of the lattice are found. IBM's seven-qubit quantum computers, ibmq_jakarta and ibm_perth, are used to compute dynamics from the trivial vacuum in one-flavor QCD with one spatial site. More generally, the Hamiltonian and quantum circuits for time evolution of $1+1$ dimensional $SU({N}_{c})$ gauge theory with ${N}_{f}$ flavors of quarks are developed, and the resource requirements for large-scale quantum simulations are estimated.

We explore observational constraints on a cosmological model with an interaction between dark energy (DE) and dark matter (DM), using a compilation of 15 measurements of the 2D baryon acoustic oscillation (BAO) (i.e., transversal) scale in combination with Planck-CMB data, to explore the parametric space of a class of interacting DE (IDE) models. We find that 2D BAO measurements can generate different observational constraints compared to the traditional approach of studying the matter clustering in the 3D BAO measurements. Contrary to the observations for the $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ and IDE models when analyzed with $\mathrm{Planck}\text{\ensuremath{-}}\mathrm{CMB}+3\mathrm{D}$ BAO data, we note that $\mathrm{Planck}\text{\ensuremath{-}}\mathrm{CMB}+2\mathrm{D}$ BAO data favor high values of the Hubble constant ${H}_{0}$. From the joint analysis with $\mathrm{Planck}\text{\ensuremath{-}}\mathrm{CMB}+2\mathrm{D}$ $\mathrm{BAO}+\text{Gaussian}$ prior on ${H}_{0}$, we find ${H}_{0}=73.4\ifmmode\pm\else\textpm\fi{}0.88\text{ }\text{…

We study the topology of the thermodynamic space of four dimensional dyonic anti--de Sitter (AdS) black hole in three different ensembles: canonical, mixed, and grand canonical ensemble. While canonical ensemble refers to the ensemble with fixed electric and magnetic charges, mixed ensemble is an ensemble where we fix magnetic charge and electric potential. In the grand canonical ensemble, potentials corresponding to both electric and magnetic charges are kept fixed. In each of these ensembles, we first compute the topological charges associated with critical points. We find that while in both canonical and mixed ensembles, there exists one conventional critical point with topological charge $\ensuremath{-}1$, in the grand canonical ensemble, we find no critical point. Then, we consider the dyonic AdS black hole as topological defects in thermodynamic space and study its local and global topology by computing the winding numbers at the defects. We observe that while the topologies of the black hole in canonical and mixed ensembles are identical with total topological charge equaling…

We discuss quantum entanglement and violation of Bell inequalities in the $H\ensuremath{\rightarrow}ZZ$ decay, in particular when the two $Z$-bosons decay into light leptons. Although such process implies an important suppression of the statistics, this is traded by clean signals from a ``quasi maximally entangled'' system, which makes it very promising to check these crucial phenomena at high energy. In this paper we devise a novel framework to extract from $H\ensuremath{\rightarrow}ZZ$ data all significant information related to this goal, in particular spin correlation observables. In this context we derive sufficient and necessary conditions for entanglement in terms of only two parameters. Likewise, we obtain a sufficient and improved condition for the violation of Bell-type inequalities. The numerical analysis shows that with a luminosity of $L=300\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ entanglement can be probed at $>3\ensuremath{\sigma}$ level. For $L=3\text{ }\text{ }{\mathrm{ab}}^{\ensuremath{-}1}$ (HL-LHC) entanglement can be probed beyond the…

We present a further observational analysis of the ${\mathrm{\ensuremath{\Lambda}}}_{\mathrm{s}}\mathrm{CDM}$ model proposed in Akarsu et al. [Phys. Rev. D 104, 123512 (2021)]. This model is based on the recent conjecture suggesting the Universe has transitioned from anti--de Sitter vacua to de Sitter vacua (viz., the cosmological constant switches sign from negative to positive), at redshift ${z}_{\ifmmode\dagger\else\textdagger\fi{}}\ensuremath{\sim}2$, inspired by the graduated dark energy model proposed in Akarsu et al. [Phys. Rev. D 101, 063528 (2020)]. ${\mathrm{\ensuremath{\Lambda}}}_{\mathrm{s}}\mathrm{CDM}$ was previously claimed to simultaneously relax five cosmological discrepancies, namely, the ${H}_{0}$, ${S}_{8}$, and ${M}_{B}$ tensions along with the $\mathrm{Ly}\text{\ensuremath{-}}\ensuremath{\alpha}$ and ${\ensuremath{\omega}}_{\mathrm{b}}$ anomalies, which prevail within the standard $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ model as well as its canonical/simple extensions. In the present work, we extend the previous analysis by constraining the model using the…

Pulsar timing arrays (PTAs) have recently found evidence for a nanohertz-frequency stochastic gravitational-wave background (SGWB). Constraining its spectral characteristics will reveal its origins. In order to achieve this, we must understand how data and modeling conditions in each pulsar influence the precision and accuracy of SGWB spectral recovery. These goals typically require many Bayesian analyses on real data sets and large-scale simulations that are slow and computationally taxing. To combat this, we have developed several new rapid approaches that instead operate on intermediate SGWB analysis products. These techniques refit SGWB spectral models to previously-computed Bayesian posterior estimates of the timing power spectra. We test our new techniques on simulated PTA data sets and the NANOGrav 12.5-year data set, where in the latter our refit posterior achieves a Hellinger distance---bounded between 0 for identical distributions and 1 for zero overlap---from the current full production-level pipeline that is $\ensuremath{\lesssim}0.1$. Our techniques are…

Measurements of weak gravitational lensing at low redshifts ($z\ensuremath{\lesssim}0.5--1$), quantified by the parameter ${S}_{8}$, favor weaker matter clustering than that expected from the standard $\mathrm{\ensuremath{\Lambda}}$ cold dark matter ($\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$) cosmological model with the parameters determined by cosmic microwave background (CMB) measurements. However, the amplitude of matter clustering at higher redshifts, as probed by lensing of the CMB, is consistent with $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$. In the literature, it has been found that the tension can be resolved by introducing a friction between dark matter and dark energy without altering the tightly constrained expansion history. Here, we show that in order to get a low ${S}_{8}$ value consistent with the findings of cosmic shear under $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$, cosmological measurements favor (at $\ensuremath{\sim}3\ensuremath{\sigma}$, in this one parameter model) a nonzero drag leading to a suppression of low-redshift power right precisely around the…

A new analysis of the distribution of matter in the Universe continues to find a discrepancy in the clumpiness of dark matter in the late and early Universe, suggesting a fundamental error in the standard cosmological model.

In this paper, utilizing the generalized off shell Helmholtz free energy, we explore the topological numbers of the four-dimensional static accelerating black hole and its AdS extension, as well as the static charged accelerating black hole and its AdS extension. Our analysis reveals a profound and significant impact of the acceleration parameter on the topological numbers associated with the static black holes; and different values (nonzero) of the acceleration parameter do not affect the topological numbers of the corresponding four-dimensional static accelerating black holes. In addition, we demonstrate that the electric charge parameter has an important effect on the topological number of the static neutral accelerating black holes, and the cosmological constant has a remarkable influence on the topological number of the static accelerating black hole. Furthermore, it is interesting to observe that the difference between the topological number of the asymptotically flat static accelerating black hole and that of its corresponding asymptotically flat static nonaccelerating black…

Neutrino fast flavor conversion (FFC) typically occurs in extremely dense neutrino environments such as those of core-collapse supernovae (CCNe). The typical distance and time scales at which FFCs take place are much smaller than those accessible to hydrodynamic simulations of CCSNe. In this paper, FFCs are schematically taken into account in spherically symmetric CCSN hydrodynamic simulations and their distinctive effects are delineated.

We propose to replace the exact amplitudes used in Monte Carlo event generators for trained machine learning regressors, with the aim of speeding up the evaluation of slow amplitudes. As a proof of concept, we study the process $gg\ensuremath{\rightarrow}ZZ$, whose leading-order amplitude is loop induced. We show that gradient boosting machines like xgboost can predict the fully differential distributions with errors below 0.1%, and with prediction times $\mathcal{O}({10}^{3})$ faster than the evaluation of the exact function. This is achieved with training times $\ensuremath{\sim}\text{ }23\text{ }\text{ }\mathrm{minutes}$ and regressors of size $\ensuremath{\lesssim}\text{ }22\text{ }\text{ }\mathrm{Mb}$. We also find that xgboost performs well over the entire phase space, while interpolation gives much larger errors in regions where the function is peaked. These results suggest a possible new avenue to speed up Monte Carlo event generators.

In a series of two papers, the authors explore the holographic duality between an eternal AdS black hole in the bulk and two copies of the boundary CFT in the thermal field double state. They provide an explicit construction in the boundary theory of an evolution operator for a bulk in-falling observer, thus making manifest the boundary emergence of the black hole horizons, the interiors, and the associated causal structure. They also elucidate that the emergence of the sharp bulk event horizon is related to the infinite N limit of the boundary theory.

We present a framework for self-consistent cosmological analyses of the full-shape anisotropic bispectrum, including the quadrupole ($\ensuremath{\ell}=2$) and hexadecapole ($\ensuremath{\ell}=4$) moments. This features a novel window-free algorithm for extracting the latter quantities from data, derived using a maximum-likelihood prescription. Furthermore, we introduce a theoretical model for the bispectrum multipoles (which does not introduce new free parameters), and test both aspects of the pipeline on several high-fidelity mocks, including the PT Challenge suite of gigantic cumulative volume. This establishes that the systematic error is significantly below the statistical threshold, both for the measurement and modeling. As a realistic example, we extract the large-scale bispectrum multipoles from BOSS DR12 and analyze them in combination with the power spectrum data. Assuming a minimal $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ model, with a BBN prior on the baryon density and a Planck prior on ${n}_{s}$, we can extract the remaining cosmological parameters directly from the…

We present the result of lattice QCD calculation of the scalar, vector and tensor form factors for the $B\ensuremath{\rightarrow}K{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ decay, across the full physical range of momentum transfer. We use the highly improved staggered quark (HISQ) formalism for all valence quarks on eight ensembles of gluon-field configurations generated by the MILC collaboration. These include four flavors of HISQ quarks in the sea, with three ensembles having the light $u/d$ quarks at physical masses. In the first fully relativistic calculation of these form factors, we use the heavy-HISQ method. This allows us to determine the form factors as a function of heavy-quark mass from the $c$ to the $b$, and so we also obtain new results for the $D\ensuremath{\rightarrow}K$ tensor form factor. The advantage of the relativistic formalism is that we can match the lattice weak currents to their continuum counterparts much more accurately than in previous calculations; our scalar and vector currents are renormalized fully nonperturbatively and we use a…

In this work we present several characteristic examples of theories of gravity and particle physics scenarios that may yield an observable energy spectrum of stochastic primordial gravitational waves, compatible with the 2023 NANOGrav observations. The resulting theories yield a flat or a peaklike energy spectrum, and we further seek the conditions which if hold true, the energy spectrum can be compatible with the recent NANOGrav stochastic gravitational wave detection. As we show, in most cases a blue tilted spectrum combined with a relatively low reheating temperature is needed, the scale of which is determined by whether the radiation domination era is ordinary or it is an abnormal radiation domination era. One intriguing Higgs-axion model, which predicts short slow-roll eras for the axion field at the post-electroweak breaking epoch, which eventually change the total equation of state parameter at the reheating era, can explain the NANOGrav signal, if a blue tilted tensor spectral index inflationary era precedes the reheating era, and a reheating temperature of the order…

We calculate the gravitational-wave (GW) signatures of detailed three-dimensional (3D) core-collapse supernova simulations spanning a range of massive stars. Most of the simulations are carried out to times late enough to capture more than 95% of the total GW emission. We find that the $f/g$-mode and $f$-mode of protoneutron star oscillations carry away most of the GW power. The $f$-mode frequency inexorably rises as the protoneutron star (PNS) core shrinks. We demonstrate that the GW emission is excited mostly by accretion plumes onto the PNS that energize modal oscillations and also high-frequency (``haze'') emission correlated with the phase of violent accretion. The duration of the major phase of emission varies with exploding progenitor, and there is a strong correlation between the total GW energy radiated and the compactness of the progenitor. Moreover, the total GW emissions vary by as much as 3 orders of magnitude from star to star. For black hole formation, the GW signal tapers off slowly and does not manifest the haze seen for the exploding models. For such failed models,…

The bumblebee gravity model, with a vector field nonminimally coupled to gravity, is a natural extension of the Einstein-Maxwell theory. In this theory, a black hole can carry a vector hair, making the metric deviate from the Schwarzschild metric. To investigate the detectability of the vector hair, we consider an extreme-mass-ratio inspiral (EMRI) system, where a stellar-mass black hole inspiraling into a supermassive black hole. We find that, with a one-year observation of an EMRI by a space-based gravitational-wave detector, we can probe the vector charge as small as $Q\ensuremath{\sim}{10}^{\ensuremath{-}3}$ in the bumblebee gravity model, which is about three orders of magnitude tighter comparing to current EHT observations.

We perform tests of general relativity (GR) with gravitational waves (GWs) from the inspiral stage of compact binaries using a theory-independent framework, which adds generic phase corrections to each multipole of a GR waveform model in frequency domain. This method has been demonstrated on Laser Interferometer Gravitational Wave Observatory-Virgo observations to provide stringent constraints on post-Newtonian predictions of the inspiral and to assess systematic biases that may arise in such parametrized tests. Here, we detail the anatomy of our framework for aligned-spin waveform models. We explore the effects of higher modes in the underlying signal on tests of GR through analyses of two unequal-mass simulated binary signals similar to GW190412 and GW190814. We show that the inclusion of higher modes improves both the precision and the accuracy of the measurement of the deviation parameters. Our testing framework also allows us to vary the underlying baseline GR waveform model and the frequency at which the non-GR inspiral corrections are tapered off. We find that to optimize the…

The authors provide a comprehensive study of the role of boundary conditions in the presence of generalized non-invertible symmetries, beginning with the question of when boundary conditions are symmetric under those symmetries. They find different categories of symmetric boundary conditions (which would be identical under normal symmetries) and discuss their relation to 't Hooft anomalies, gauging, and RG flows.

The bumblebee gravity model is a vector-tensor theory of gravitation where the vector field nonminimally couples to the Ricci tensor. By investigating the vacuum field equations with spherical symmetry, we find two families of black-hole (BH) solutions in this model: one has a vanishing radial component of the vector field and the other has a vanishing radial component of the Ricci tensor. When the coupling between the vector field and the Ricci tensor is set to zero, the first family becomes the Reissner-Nordstr\"om solution while the second family degenerates to the Schwarzschild solution with the vector field being zero. General numerical solutions in both families are obtained for nonzero coupling between the vector field and the Ricci tensor. Besides BH solutions, we also reveal the existence of solutions that have a nonvanishing $tt$-component of the metric on the supposed event horizon where the $rr$-component of the metric diverges while the curvature scalars are finite. These solutions are not supported by existing observations but present certain properties that are of…

Topological duality defects arise as codimension one generalized symmetry operators in quantum field theories (QFTs) with a duality symmetry. Recent investigations have shown that in the case of 4D $\mathcal{N}=4$ Super Yang-Mills (SYM) theory, an appropriate choice of (complexified) gauge coupling and global form of the gauge group can lead to a rather rich fusion algebra for the associated defects, leading to examples of noninvertible symmetries. In this work we present a top down construction of these duality defects which generalizes to QFTs with lower supersymmetry, where other 0-form symmetries are often present. We realize the QFTs of interest via D3-branes probing $X$ a Calabi-Yau threefold cone with an isolated singularity at the tip of the cone. The IIB duality group descends to dualities of the 4D worldvolume theory. Nontrivial codimension one topological interfaces arise from configurations of 7-branes ``at infinity'' which implement a suitable $SL(2,\mathbb{Z})$ transformation when they are crossed. Reduction on the boundary topology $\ensuremath{\partial}X$ results in…

Neutron stars can accumulate asymmetric dark matter (ADM) in their interiors, which affects the neutron star's measurable properties and makes compact objects prime targets to search for ADM. In this work, we use Bayesian inference to explore potential neutron star mass-radius measurements, from current and future x-ray telescopes, to constrain the bosonic ADM parameters for the case where bosonic ADM has accumulated in the neutron star interior. We find that the current uncertainties in the baryonic equation of state do not allow for constraints on the ADM parameter space to be made. However, we also find that ADM cannot be excluded and the inclusion of bosonic ADM in neutron star cores relaxes the constraints on the baryonic equation of state space. If the baryonic equation of state were more tightly constrained independent of ADM, we find that statements about the ADM parameter space could be made. In particular, we find that the high bosonic ADM particle mass (${m}_{\ensuremath{\chi}}$) and low effective self-interaction strength…

In the analysis of a binary black hole coalescence, it is necessary to include gravitational self-interactions in order to describe the transition of the gravitational wave signal from the merger to the ringdown stage. In this paper we study the phenomenology of the generation and propagation of nonlinearities in the ringdown of a Schwarzschild black hole, using second-order perturbation theory. Following earlier work, we show that the Green's function and its causal structure determines how both first-order and second-order perturbations are generated, and hence highlight that both of these solutions share some physical properties. In particular, we discuss the sense in which both linear and quadratic quasinormal modes (QNMs) are generated in the vicinity of the peak of the gravitational potential barrier (loosely referred to as the light ring). Among the second-order perturbations, there are solutions with linear QNM frequencies (whose amplitudes are thus renormalized from their linear values), as well as quadratic QNM frequencies with a distinct spectrum. Moreover, we show using…

We present two complementary NuSTAR x-ray searches for keV-scale dark matter decaying to monoenergetic photons in the Milky Way halo. In the first, we utilize the known intensity pattern of unfocused stray light across the detector planes---the dominant source of photons from diffuse sources---to separate astrophysical emission from internal instrument backgrounds using $\ensuremath{\sim}7$- Ms/detector deep blank-sky exposures. In the second, we present an updated parametric model of the full NuSTAR instrument background, allowing us to leverage the statistical power of an independent $\ensuremath{\sim}20$-Ms/detector stacked exposures spread across the sky. Finding no evidence of anomalous x-ray lines using either method, we set limits on the active-sterile mixing angle ${\mathrm{sin}}^{2}(2\ensuremath{\theta})$ for sterile-neutrino masses 6--40 keV. The first key result is that we strongly disfavor a $\ensuremath{\sim}7$-keV sterile neutrino decaying into a 3.5-keV photon. The second is that we derive leading limits on sterile neutrinos with masses $\ensuremath{\sim}15--18\text{…

We leverage recent breakthrough calculations using second-order gravitational self-force (2GSF) theory to improve both the gravitational-mode amplitudes and radiation-reaction force in effective-one-body (EOB) waveform models. We achieve this by introducing new calibration parameters in the SEOBNRv5HM mode amplitudes, and matching them to the newly available 2GSF energy-flux multipolar data for quasicircular nonspinning binary black holes. We find that this significantly improves the SEOBNRv5HM energy flux, when compared with numerical-relativity (NR) simulations of binary black holes with mass ratios between $1\ensuremath{\mathbin:}1$ and $1\ensuremath{\mathbin:}20$. Moreover, we find that, once the conservative part of the SEOBNRv5 dynamics is calibrated, the SEOBNRv5HM waveform model with 2GSF information reproduces the binding energy of NR simulations more accurately, providing a powerful check of the consistency and naturalness of the EOB approach. While we only include nonspinning 2GSF information, the more accurate binding energy and energy flux carry over to the SEOBNRv5…

We study extreme mass-ratio binary systems in which a stellar mass compact object spirals into a supermassive black hole surrounded by a scalar cloud. Scalar clouds can form through superradiant instabilities of massive scalar fields around spinning black holes and can also serve as a proxy for dark matter halos. Our framework is fully relativistic and assumes that the impact of the cloud on the geometry can be treated perturbatively. As a proof of concept, here we consider a point particle in circular, equatorial motion around a nonspinning black hole surrounded either by a spherically symmetric or a dipolar nonaxisymmetric scalar cloud, but the framework can in principle be generalized to generic black hole spins and scalar cloud geometries. We compute the leading-order power lost by the point particle due to scalar radiation and show that, in some regimes, it can dominate over gravitational-wave emission. We confirm the presence of striking signatures due to the presence of a scalar cloud that had been predicted using Newtonian approximations, such as resonances that can give…

We refine previous investigations on de Sitter space and extremal surfaces anchored at the future boundary ${I}^{+}$. Since such surfaces do not return, they require extra data or boundary conditions in the past (interior). In entirely Lorentzian de Sitter spacetime, this leads to future-past timelike surfaces stretching between ${I}^{\ifmmode\pm\else\textpm\fi{}}$. Apart from an overall $\ensuremath{-}i$ factor (relative to spacelike surfaces in $AdS$) their areas are real and positive. With a no-boundary type boundary condition, the top half of these timelike surfaces joins with a spacelike part on the hemisphere giving a complex-valued area. Motivated by these, we describe two aspects of ``time-entanglement'' in simple toy models in quantum mechanics. One is based on a future-past thermofield double type state entangling timelike separated states, which leads to entirely positive structures. Another is based on the time evolution operator and reduced transition amplitudes, which leads to complex-valued entropy.

Circumambient and galactic-scale environments are intermittently present around black holes, especially those residing in active galactic nuclei. As supermassive black holes impart energy on their host galaxy, so the galactic environment affects the geodesic dynamics of solar-mass objects around supermassive black holes and subsequently the gravitational waves emitted from such nonvacuum extreme-mass-ratio binaries. Only recently an exact general-relativistic solution has been found that describes a Schwarzschild black hole immersed in a dark matter halo profile of the Hernquist type. We perform an extensive analysis generic geodesics delving in such nonvacuum spacetimes and compare our results with those obtained in vacuum Schwarzschild spacetime, as well as calculate their dominant gravitational-wave emission. Our findings indicate that the radial and polar oscillation frequency ratios, which designate resonances, descend deeper into the extreme gravity regime as the compactness of the halo increases. This translates to a gravitational redshift of nonvacuum geodesics and their…

In the recent proposal [S. W. Wei et al., Black Hole Solutions as Topological Thermodynamic Defects, Phys. Rev. Lett. 129, 191101 (2022).], the black holes were viewed as topological thermodynamic defects by using the generalized off shell free energy. In this paper, we follow such proposal to study the local and global topological natures of the Gauss-Bonnet black holes in anti--de Sitter (AdS) space. The local topological natures are reflected by the winding numbers, where the positive and negative winding numbers correspond to the stable and unstable black hole branches. The global topological natures are reflected by the topological numbers, which are defined as the sum of the winding numbers for all black hole branches and can be used to classify the black holes into different classes. When the charge is present, we find that the topological number is independent on the values of the parameters, and the charged Gauss-Bonnet AdS black holes can be divided into the same class of the Reissner-Nordstr\"om anti-de Sitter black hole black holes with the same topological number 1.…

In this work, we develop a universal picture from topology in the thermodynamic parameters space to describe first order phase transitions of black holes. By employing an off-shell internal energy, we find two types of topological defects. The first is normal, describing black holes which move with a nonzero velocity and acceleration, in a central force field. The second type of defects are exotic: they are static in the space, not describing black holes but encoding information about first order transitions. For each defect, we assign a winding number and an inertial mass. By studying neutral and charged black holes in asymptotically anti--de Sitter space, we show that first order transitions can be viewed as a once or twice interchange of winding numbers between black holes and the exotic defects, through wired action at a distance. This corresponds to the usual notion: a smaller black hole grows into a larger black hole or vice versa. However, our topological analysis illustrates that the transition can also be locally interpreted as virtual collisions between black holes and the…

We assess the robustness of $\mathrm{\ensuremath{\Lambda}}$ cold dark matter ($\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$) results from the full-shape analysis of BOSS power spectrum using the one-loop prediction of the effective field theory of large-scale structure (EFTofLSS). In former EFT analyses, the two public likelihoods pybird and class-pt lead to results in agreement only at the $1\ensuremath{\sigma}$ level, which may appear unsatisfactory given that they are derived from the same BOSS dataset and the same theory model. To identify the origin of the difference, we perform a thorough comparison of the various analyses choices made between the two pipelines. We find that most of the difference can be attributed to the choices of prior on the EFT parameters, dubbed ``West-coast'' (WC) prior and ``East-coast'' (EC) prior, respectively associated to pybird and class-pt. In particular, because posteriors are non-Gaussian, projection effects from the marginalization over the EFT parameters shift the posterior mean of the cosmological parameters with respect to the maximum a…

A framework for quantum simulations of real-time weak decays of hadrons and nuclei in a two-flavor lattice theory in one spatial dimension is presented. A single generation of the Standard Model is found to require 16 qubits per spatial lattice site after mapping to spin operators via the Jordan-Wigner transformation. Both quantum chromodynamics and flavor-changing weak interactions are included in the dynamics, the latter through four-Fermi effective operators. Quantum circuits that implement time evolution in this lattice theory are developed and run on Quantinuum's H1-1 20-qubit trapped ion system to simulate the $\ensuremath{\beta}$-decay of a single baryon on one lattice site. These simulations include the initial state preparation and are performed for both one and two Trotter time steps. The potential intrinsic error-correction properties of this type of lattice theory are discussed, and the leading lattice Hamiltonian required to simulate $0\ensuremath{\nu}\ensuremath{\beta}\ensuremath{\beta}$-decay of nuclei induced by a neutrino Majorana mass term is provided.

Detecting gravitational waves from coalescing compact binaries allows us to explore the dynamical, nonlinear regime of general relativity and constrain modifications to it. Some of the gravitational-wave events observed by the LIGO-Virgo Collaboration have sufficiently high signal-to-noise ratio in the merger, allowing us to probe the relaxation of the remnant black hole to its final, stationary state---the so-called black-hole ringdown, which is characterized by a set of quasinormal modes. Can we use the ringdown to constrain deviations from general relativity, as predicted by several of its contenders? Here, we address this question by using an inspiral-merger-ringdown waveform model in the effective-one-body formalism, augmented with a parametrization of the ringdown based on an expansion in the final black hole's spin. We give a prescription on how to include in this waveform model, the quasinormal mode frequencies calculated on a theory-by-theory basis. In particular, we focus on theories that modify general relativity by higher-order curvature corrections, namely,…

Gravitational waves (GWs) create correlations in the arrival times of pulses from different pulsars. The expected correlation μ ( γ ) as a function of the angle γ between the directions to two pulsars was calculated by Hellings and Downs for an isotropic and unpolarized GW background, and several pulsar timing array (PTA) collaborations are working to observe these. We ask: given a set of noise-free observations, are they consistent with that expectation? To answer this, we calculate the expected variance σ 2 ( γ ) in the correlation for a single GW point source, as pulsar pairs with fixed separation angle γ are swept around the sky. We then use this to derive simple analytic expressions for the variance produced by a set of discrete point sources uniformly scattered in space for two cases of interest: (1) point sources radiating GWs at the same frequency, generating confusion noise, and (2) point sources radiating GWs at distinct nonoverlapping frequencies. By averaging over all pulsar sky positions at fixed separation angle γ , we show how this variance may be cleanly split into…

A collective effort involving various theoretical frameworks results in the successful gravitational wave phasing of nonspinning compact binary systems on quasicircular orbits up to the 4.5 post-Newtonian order.

Some stochastic gravitational wave background models from the early Universe has a cutoff frequency close to 100 MHz, due to the horizon of the inflationary phase. To detect gravitational waves at such frequencies, resonant electromagnetic cavities are very suitable. In this work, we study the expected frequency response of such detectors using a brand new approach, and show how we could use them to probe this cutoff frequency and also the energy density per frequency of this stochastic background. This paper paves the way for further experimental studies to probe the most ancient relic of the Universe.

With the aim of exploring the evidence for or against phase transitions in cold and dense baryonic matter, the inference of the sound speed and equation of state for dense matter in neutron stars is extended in view of recent new observational data. The impact of the heavy ($2.35{M}_{\ensuremath{\bigodot}}$) black-widow pulsar PSR J0952-0607 and the unusually light supernova remnant HESS J1731-347 is inspected. In addition, a detailed reanalysis is performed of the low-density constraint based on chiral effective field theory and of the perturbative QCD constraint at asymptotically high densities, in order to clarify the influence of these constraints on the inference procedure. The trace anomaly measure, $\mathrm{\ensuremath{\Delta}}=1/3\ensuremath{-}P/ϵ$, is also computed and discussed. A systematic Bayes factor assessment quantifies the evidence (or nonevidence) of low averaged sound speeds $({c}_{s}^{2}\ensuremath{\le}0.1)$, a prerequisite for a phase transition, within the range of densities realized in the core of neutron stars. One of the consequences of including PSR…

We reduce the study of perturbations of rotating black holes in higher-derivative extensions of general relativity to a system of decoupled radial equations that stem from a set of universal Teukolsky equations. We detail a complete computational strategy to obtain these decoupled equations in general higher-derivative theories. We apply this to six-derivative gravity to compute the shifts in the quasinormal mode frequencies with respect to those of Kerr black holes in general relativity. At linear order in the angular momentum we reproduce earlier results obtained with a metric perturbation approach. In contrast with this earlier work, however, the method given here applies also to postmerger black holes with significant spin, which are of particular observational interest.

This study revisits bounds on axion-like particles (ALPs) derived from supernovae, where they may be generated in stellar interiors before decaying to photons. Past works have used observations from SN1987A to exclude ALP masses of 10s of MeV, due to the absence of a signal in the Gamma Ray Spectrometer aboard the Solar Maximum Mission satellite. The present paper argues that such particles would generate a fireball of plasma around the supernova, ultimately leading to a much lower energy photon signal, thus invalidating the old bounds in this scenario. However, the authors find that data from the Pioneer Venus Orbiter can be used to set similar limits.

We summarize the recent progress of the Axion Longitudinal Plasma Haloscope (ALPHA) Consortium, a new experimental collaboration to build a plasma haloscope to search for axions and dark photons. The plasma haloscope is a novel method for the detection of the resonant conversion of light dark matter to photons. ALPHA will be sensitive to QCD axions over almost a decade of parameter space, potentially discovering dark matter and resolving the strong $CP$ problem. Unlike traditional cavity haloscopes, which are generally limited in volume by the Compton wavelength of the dark matter, plasma haloscopes use a wire metamaterial to create a tuneable artificial plasma frequency, decoupling the wavelength of light from the Compton wavelength and allowing for much stronger signals. We develop the theoretical foundations of plasma haloscopes and discuss recent experimental progress. Finally, we outline a baseline design for ALPHA and show that a full-scale experiment could discover QCD axions over almost a decade of parameter space.

This work presents the first gravitational lensing measurements with the 3G camera on the South Pole Telescope (SPT). Notably, it places constraints on key cosmological parameters consistent with those from SPT-SZ, SPTpol, ACT, and Planck.

Analyses of the full shape of the Baryon Oscillation Spectroscopic Survey (BOSS) DR12 power spectrum using the one-loop prediction from the effective field theory of large-scale structures (EFTBOSS) have led to new constraints on extensions to the $\mathrm{\ensuremath{\Lambda}}$ cold dark matter model, such as early dark energy (EDE), which has been suggested as a resolution to the ``Hubble tension.'' In this paper, we reassess the constraining power of the EFTBOSS on EDE in light of a correction to the normalization of BOSS window functions. Overall we find that constraints from EFTBOSS on EDE are weakened and represent a small change compared to constraints from Planck and the conventional baryon acoustic $\mathrm{oscillation}/f{\ensuremath{\sigma}}_{8}$ measurements. The combination of Planck data with EFTBOSS provides a bound on the maximal fractional contribution of EDE ${f}_{\mathrm{EDE}}<0.083$ at 95% C.L. (compared to $<0.054$ with the incorrect normalization and $<0.088$ without full-shape data) and the Hubble tension is reduced to $2.1\ensuremath{\sigma}$. However, the…

Waveform models are essential for gravitational-wave (GW) detection and parameter estimation of coalescing compact-object binaries. More accurate models are required for the increasing sensitivity of current and future GW detectors. The effective-one-body (EOB) formalism combines the post-Newtonian (PN) and small mass-ratio approximations with numerical-relativity results, and produces highly accurate inspiral-merger-ringdown waveforms. In this paper, we derive the analytical precessing-spin two-body dynamics for the SEOBNRv5 waveform model, which has been developed for the upcoming LIGO-Virgo-KAGRA observing run. We obtain an EOB Hamiltonian that reduces to the exact Kerr Hamiltonian in the test-mass limit. It includes the full 4PN precessing-spin information, and is valid for generic compact objects (i.e., for black holes or neutron stars). We also build an efficient and accurate EOB Hamiltonian that includes partial precessional effects, notably orbit-averaged in-plane spin effects for circular orbits, and derive 4PN-expanded precessing-spin equations of motion, consistent with…

Eccentric compact binary mergers are significant scientific targets for current and future gravitational wave observatories. To detect and analyze eccentric signals, there is an increasing effort to develop waveform models, numerical relativity simulations, and parameter estimation frameworks for eccentric binaries. Unfortunately, current models and simulations use different internal parametrizations of eccentricity in the absence of a unique natural definition of eccentricity in general relativity, which can result in incompatible eccentricity measurements. In this paper, we adopt a standardized definition of eccentricity and mean anomaly based solely on waveform quantities and make our implementation publicly available through an easy-to-use python package, gw_eccentricity. This definition is free of gauge ambiguities, has the correct Newtonian limit, and can be applied as a postprocessing step when comparing eccentricity measurements from different models. This standardization puts all models and simulations on the same footing and enables direct comparisons between eccentricity…

Early dark energy (EDE) offers a solution to the so-called Hubble tension. Recently, it was shown that the constraints on EDE using Markov Chain Monte Carlo are affected by prior volume effects. The goal of this paper is to present constraints on the fraction of EDE, ${f}_{\mathrm{EDE}}$, and the Hubble parameter, ${H}_{0}$, which are not subject to prior volume effects. We conduct a frequentist profile likelihood analysis considering data from Planck cosmic microwave background, BOSS full-shape galaxy clustering, DES galaxy clustering and weak lensing, and the cosmic distance ladder from SH0ES. Contrary to previous findings, we find that ${H}_{0}$ for the EDE model is in statistical agreement with the SH0ES direct measurement at $<1.7\ensuremath{\sigma}$ for all datasets. For our baseline dataset ($Planck+\mathrm{BOSS}$), we obtain ${f}_{\mathrm{EDE}}=0.087\ifmmode\pm\else\textpm\fi{}0.037$ and ${H}_{0}=70.57\ifmmode\pm\else\textpm\fi{}1.36\text{ }\text{ }\mathrm{km}/\mathrm{s}/\mathrm{Mpc}$ at 68% confidence limit. We conclude that EDE is a viable solution to the Hubble tension.

Gravitational-wave memory effects arise from nonoscillatory components of gravitational-wave signals, and they are predictions of general relativity in the nonlinear regime that have close connections to the asymptotic properties of isolated gravitating systems. There are many types of memory effects that have been studied in the literature. In this paper we focus on the ``displacement'' and ``spin'' memories, which are expected to be the largest of these effects from sources such as the binary black hole mergers which have already been detected by LIGO and Virgo. The displacement memory is a change in the relative separation of two initially comoving observers due to a burst of gravitational waves, whereas the spin memory is a portion of the change in relative separation of observers with initial relative velocity. As both of these effects are small, LIGO, Virgo, and KAGRA can only detect memory effects from individual events that are much louder (and thus rarer) than those that have been detected so far. By combining data from multiple events, however, these effects could be…

We study the nonlinear dynamics of binary black hole systems with scalar charge by numerically evolving the full equations of motion for shift-symmetric Einstein scalar Gauss-Bonnet gravity. We consider quasicircular binaries with different mass-ratios, varying the Gauss-Bonnet coupling and quantifying its impact on the emitted scalar and gravitational waves. We compare our numerical results to post-Newtonian calculations of the radiation emitted during the inspiral. We demonstrate the accuracy of the leading-order terms in post-Newtonian theory in modeling the amplitude of the scalar waveform, but find that, at least for the last few orbits before merger, the currently available post-Newtonian theory is not sufficient to model the dephasing of the gravitational wave signal in this theory. We further find that there is non-negligible nonlinear enhancement in the scalar field at merger, but that the effect on the peak gravitational wave emission is small.

We consider a metric-affine extension to the gravitational sector of the Standard Model extension for the Lorentz-violating coefficients $u$ and ${s}^{\ensuremath{\mu}\ensuremath{\nu}}$. The general results, which are applied to a specific model called metric-affine bumblebee gravity, are obtained. A Schwarzschild-like solution, incorporating effects of the Lorentz symmetry breaking through the coefficient $X=\ensuremath{\xi}{b}^{2}$, is found. Furthermore, a complete study of the geodesic trajectories of particles is accomplished in this background, emphasizing the departure from general relativity. We also compute the advance of Mercury's perihelion and the deflection of light within the context of the weak-field approximation, and we verify that there exist two new contributions ascribed to the Lorentz symmetry breaking. As a phenomenological application, we compare our theoretical results with observational data in order to estimate the coefficient $X$.

It was conjectured that a particular two-dimensional gravity, Jackiw--Teitelboim (JT) gravity, is dual to a single-trace one-matrix Random Matrix Model (RMM). The authors extend this duality to JT gravity minimally coupled to a free massive scalar field and a single-trace two-matrix model. They study in detail the matching of genus zero one- and two-boundary expectation values in the matrix model to the gravitational disk correlators.

We introduce a model for matter genesis in which both the baryonic and dark matter asymmetries originate from a first-order phase transition in a dark sector with an $SU(3)\ifmmode\times\else\texttimes\fi{}SU(2)\ifmmode\times\else\texttimes\fi{}U(1)$ gauge group and minimal matter content. In the simplest scenario, we predict that dark matter is a dark antineutron with mass of either ${m}_{\overline{n}}=1.36\text{ }\text{ }\mathrm{GeV}$ or ${m}_{\overline{n}}=1.63\text{ }\text{ }\mathrm{GeV}$. Alternatively, dark matter may be comprised of equal numbers of dark antiprotons and pions. In either scenario, this model is highly discoverable through both dark matter direct detection and dark photon search experiments. The strong dark matter self-interactions may ameliorate small-scale structure problems, while the strongly first-order phase transition may be confirmed at future gravitational wave observatories.

Drell-Yan production is one of the precision cornerstones of the LHC, serving as calibration for measurements such as the $W$-boson mass. Its extreme precision at the level of 1% challenges theory predictions at the highest level. We present the first independent calculation of Drell-Yan production at order ${\ensuremath{\alpha}}_{s}^{3}$ in transverse-momentum (${q}_{T}$) resummation improved perturbation theory. Our calculation reaches the state-of-the-art through inclusion of the recently published four loop rapidity anomalous dimension and three loop massive axial-vector contributions. We compare to the most recent data from CMS with fiducial and differential cross-section predictions and find excellent agreement at the percent level. Our resummed calculation including the matching to $Z+\text{jet}$ production at NNLO is publicly available in the upcoming cute-mcfm 10.3 release and allows for theory-data comparison at an unprecedented level.

Gravitational wave (GW) sources at cosmological distances can be used to probe the expansion rate of the Universe. GWs directly provide a distance estimation of the source but no direct information on its redshift. The optimal scenario to obtain a redshift is through the direct identification of an electromagnetic (EM) counterpart and its host galaxy. With almost 100 GW sources detected without EM counterparts (dark sirens), it is becoming crucial to have statistical techniques able to perform cosmological studies in the absence of EM emission. Currently, only two techniques for dark sirens are used on GW observations; the spectral siren method, which is based on the source-frame mass distribution to estimate conjointly cosmology and the source's merger rate, and the galaxy survey method, which uses galaxy surveys to assign a probabilistic redshift to the source while fitting cosmology. It has been recognized, however, that these two methods are two sides of the same coin. In this paper, we present a novel approach to unify these two methods. We apply this approach to several…

We present a lattice-QCD calculation of the light-quark connected contribution to window observables associated with the leading-order hadronic vacuum polarization contribution to the anomalous magnetic moment of the muon, ${a}_{\ensuremath{\mu}}^{\mathrm{HVP},\mathrm{LO}}$. We employ the MILC Collaboration's isospin-symmetric QCD gauge-field ensembles, which contain four flavors of dynamical highly improved staggered quarks with four lattice spacings between $a\ensuremath{\approx}0.06--0.15\text{ }\text{ }\mathrm{fm}$ and close-to-physical quark masses. We consider several effective-field-theory-based schemes for finite volume and other lattice corrections and combine the results via Bayesian model averaging to obtain robust estimates of the associated systematic uncertainties. After unblinding, our final results for the intermediate and ``W2'' windows are ${a}_{\ensuremath{\mu}}^{ll,\mathrm{W}}(\text{conn})=206.6(1.0)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}10}$ and…

A search for dark matter axions with masses $>10\text{ }\text{ }\mathrm{\ensuremath{\mu}}\mathrm{eV}/{\mathrm{c}}^{2}$ has been performed using the HAYSTAC experiment's squeezed state receiver to achieve subquantum limited noise. This work includes details of the design and operation of the experiment previously used to search for axions in the mass ranges 16.96--17.12 and $17.14--17.28\text{ }\text{ }\mathrm{\ensuremath{\mu}}\mathrm{eV}/{\mathrm{c}}^{2}$ (4.100--4.140 GHz and 4.145--4.178 GHz) as well as upgrades to facilitate an extended search at higher masses. These upgrades include improvements to the data acquisition routine which have reduced the effective dead time by a factor of 5, allowing for the new region to be scanned $\ensuremath{\sim}1.6$ times faster with comparable sensitivity. No statistically significant evidence of an axion signal is found in the range $18.44--18.71\text{ }\text{ }\mathrm{\ensuremath{\mu}}\mathrm{eV}/{\mathrm{c}}^{2}$ (4.459--4.523 GHz), leading to an aggregate upper limit exclusion at the 90% level on the axion-photon coupling of…

Our present understanding of the reheating phase is incomplete due to a lack of observations. Apart from its cosmological implications, the reheating should play a vital role in particle physics and inflation model building. Conventionally, reheating dynamics are modeled by invoking arbitrary coupling among the inflaton and daughter fields. Such an approach lacks robust cosmological predictions, due to its arbitrary couplings, and is difficult to verify through observation. In this paper, we propose a minimal reheating scenario, where the inflaton is coupled with all the daughter fields only gravitationally. Besides being successful in reheating the Universe, the scenario offers a strong cosmological prediction of the primordial gravitational wave spectrum and discards a large number of possible models of dark matter and inflation that are otherwise consistent with Planck.

The James Webb Space Telescope has detected surprisingly luminous early galaxies that indicate a tension with the $\mathrm{\ensuremath{\Lambda}}$ cold dark matter. Motivated by scenarios including axion miniclusters or primordial black holes, we consider power-law modifications of the matter power spectrum. We show that the tension could be resolved if dark matter consists of $2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}18}\text{ }\text{ }\mathrm{eV}$ axions or if a fraction ${f}_{\mathrm{PBH}}>0.005$ of dark matter is composed of compact heavy $4\ifmmode\times\else\texttimes\fi{}{10}^{6}{M}_{\ensuremath{\bigodot}}({f}_{\mathrm{PBH}}/0.005{)}^{\ensuremath{-}1}$ structures such as primordial black hole clusters. However, in both cases, the star formation efficiency needs to be significantly enhanced.

We use HPQCD's recent lattice QCD determination of $B\ensuremath{\rightarrow}K$ scalar, vector and tensor form factors to determine Standard Model differential branching fractions for $B\ensuremath{\rightarrow}K{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$, $B\ensuremath{\rightarrow}K{\ensuremath{\ell}}_{1}^{+}{\ensuremath{\ell}}_{2}^{\ensuremath{-}}$ and $B\ensuremath{\rightarrow}K\ensuremath{\nu}\overline{\ensuremath{\nu}}$. These form factors are calculated across the full ${q}^{2}$ range of the decay and have smaller uncertainties than previous work, particularly at low ${q}^{2}$. For $B\ensuremath{\rightarrow}K{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ we find the Standard Model branching fraction in the ${q}^{2}$ region below the squared $J/\ensuremath{\psi}$ mass to exceed the LHCb results, with tensions as high as $4.7\ensuremath{\sigma}$ for ${B}^{+}\ensuremath{\rightarrow}{K}^{+}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}$. For the high ${q}^{2}$ region we see $3\ensuremath{\sigma}$ tensions. The tensions are much reduced by…

We compute the spectrum of linearized gravitational excitations of black holes with substantial angular momentum in the presence of higher-derivative corrections to general relativity. We do so perturbatively to leading order in the higher-derivative couplings and up to order fourteen in the black hole angular momentum. This allows us to accurately predict quasinormal mode frequencies of black holes with spins up to about 70% of the extremal value. For some higher-derivative corrections, we find that sizable rotation enhances the frequency shifts by almost an order of magnitude relative to the static case.

In this work, we construct promising model-building routes towards SO(10) grand unified theory inflation and examine their ability to explain the recent pulsar timing arrays (PTAs) results hinting at a stochastic gravitational wave (GW) background at nanohertz frequencies. We consider a supersymmetric framework within which the so-called doublet-triplet splitting problem is solved without introducing fine-tuning. Additionally, realistic fermion masses and mixings, gauge coupling unification, and cosmic inflation are incorporated by utilizing superfields with representations no higher than the adjoint representation. Among the three possible scenarios, two of these cases require a single adjoint Higgs field, and do not lead to cosmic strings. In contrast, the third scenario featuring two adjoints, can lead to a network of metastable cosmic strings that generates a GW background contribution compatible with the recent PTA findings and testable by various ongoing and upcoming GW observatories.

In the curvaton scenario, the curvature perturbation is generated after inflation at the curvaton decay, which may have a prominent non-Gaussian effect. For a model with a nontrivial kinetic term, an enhanced curvature perturbation on a small scale can be realized, which can lead to copious production of primordial black holes (PBHs) and induce secondary gravitational waves (GWs). Using the probability distribution function (PDF) which takes full nonlinear effects into account, we calculate the PBH formation. We find that under the assumption that thus formed PBHs would not overclose the Universe, the non-Gaussianity of the curvature perturbation can be well-approximated by the local quadratic form, which can be used to calculate the induced GWs. In this model the limit of large non-Gaussianity can be reached when the curvaton energy fraction $r$ is small at the moment of curvaton decay. We also show that in the $r\ensuremath{\rightarrow}1$ limit the PDF is similar to that of ultraslow-roll inflation.

We present the first nonlinear lattice simulation of an axion field coupled to a U(1) gauge field during inflation. We use it to fully characterize the statistics of the primordial curvature perturbation $\ensuremath{\zeta}$. We find high-order statistics to be essential in describing non-Gaussianity of $\ensuremath{\zeta}$ in the linear regime of the theory. On the contrary, non-Gaussianity is suppressed when the dynamics become nonlinear. This relaxes the bounds from overproduction of primordial black holes, allowing for an observable gravitational waves signal at pulsar timing array and interferometer scales. Our work establishes lattice simulations as a crucial tool to study the inflationary epoch and its predictions.

We investigate the shadow of an exact black hole solution of Einstein's equations recently proposed by Cardoso et al., to describe a supermassive black hole immersed in a dark matter halo. We analyze and discuss the light rings and the gravitational lensing of this spacetime comparing them with an isolated Schwarzschild black hole. Using backward ray-tracing techniques, we study the shadows cast by such black hole when illuminated by a celestial sphere that emits radiation isotropically. We find that when the dark matter distribution concentrates near the event horizon of the black hole, multiple light rings emerge. In this high compactness regime, the shadows and gravitational lensing are significantly different from the Schwarzschild one. We also use the M87* and SgrA* shadow data, obtained by the Event Horizon Telescope collaboration, to constrain the parameters of the dark matter halo.

Just like light, gravitational waves (GWs) are deflected and magnified by gravitational fields as they propagate through the Universe. However, their low frequency, phase coherence and feeble coupling to matter allow for distinct lensing phenomena, such as diffraction and central images, that are challenging to observe through electromagnetic sources. Here we explore how these phenomena can be used to probe features of gravitational lenses. We focus on two variants of the singular isothermal sphere, with (1) a variable slope of the matter density and (2) a central core. We describe the imprints of these features in the wave- and geometric-optics regimes, including the prospect of detecting central images. We forecast the capacity of LISA and advanced LIGO to study strongly lensed signals and measure the projected lens mass, impact parameter, and slope or core size. A broad range of lens masses allows all parameters to be measured with precision up to $\ensuremath{\sim}1/\mathrm{SNR}$, despite large degeneracies. Thanks to wave-optics corrections, all parameters can be measured, even…

We return to interpreting the historical SN 1987A neutrino data from a modern perspective. To this end, we construct a suite of spherically symmetric supernova models with the prometheus-vertex code, using four different equations of state and five choices of final baryonic neutron-star (NS) mass in the $1.36--1.93{M}_{\ensuremath{\bigodot}}$ range. Our models include muons and proto-neutron star (PNS) convection by a mixing-length approximation. The time-integrated signals of our $1.44{M}_{\ensuremath{\bigodot}}$ models agree reasonably well with the combined data of the four relevant experiments, IMB, Kam-II, BUST, and LSD, but the high-threshold IMB detector alone favors a NS mass of $1.7--1.8{M}_{\ensuremath{\bigodot}}$, whereas Kam-II alone prefers a mass around $1.4{M}_{\ensuremath{\bigodot}}$. The cumulative energy distributions in these two detectors are well-matched by models for such NS masses, and the previous tension between predicted mean neutrino energies and the combined measurements is gone, with and without flavor swap. Generally, our predicted signals do not…

GW190521 is a short-duration, low-frequency gravitational-wave signal in the LIGO-Virgo catalogue. The signal is consistent with the ringdown and possibly some of the inspiral-merger of an intermediate-mass binary black-hole coalescence. We find that previous models of the quasinormal mode spectrum in the ringdown of GW190521 give remnant mass and spin estimates which are not fully consistent with those of many inspiral-merger-ringdown waveforms. In our own analysis, we find that ringdown models which include both the angular $l=2$, $m=1$ and $l=m=2$ fundamental quasinormal modes are in full agreement with most inspiral-merger-ringdown waveforms, and in particular with the numerical relativity surrogate NRSur7dq4. We also find some support for including the $l=3$, $m=2$ fundamental quasinormal mode in our fits, building on Capano et al.'s findings regarding a higher-frequency subdominant mode. We propose an interpretation of our GW190521 ringdown model that links precession to the excitation of $l\ensuremath{\ne}m$ quasinormal modes, but we do not rule out eccentricity or other…

Neutrino-neutrino forward scatterings potentially induce collective neutrino oscillation in dense neutrino gases in astrophysical sites such as core-collapse supernovae (CCSNe) and binary neutron star mergers (BNSMs). In this paper, we present a detailed study of fast neutrino-flavor conversion (FFC), paying special attention to asymptotic states, by means of stability analysis and local simulations with a periodic boundary condition. We find that asymptotic states can be characterized by two key properties of FFC: (1) the conservation of lepton number for each flavor of neutrinos and (2) the disappearance of ELN (electron neutrino-lepton number)-XLN (heavy-leptonic one) angular crossings in the spatial- or time-averaged distributions. The system that initially has the positive (negative) ELN-XLN density reaches a flavor equipartition in the negative (positive) ELN-XLN angular directions, and the other part compensates it to preserve the conservation laws. These properties of FFCs offer an approximate scheme determining the survival probability of neutrinos in asymptotic states…

We compare numerical relativity (NR) data on the scattering of equal-mass, nonspinning binary black holes to various analytical predictions based on post-Minkowskian (PM) results. While the usual sequence of PM-expanded scattering angles shows a rather poor convergence towards NR data, we find that a reformulation of PM information in terms of effective-one-body radial potentials leads to remarkable agreement with NR data, especially when using the radiation-reacted 4PM information. Using Firsov's inversion formula we directly extract, for the first time, from NR simulations a (radiation-reacted) gravitational potential describing the scattering of equal-mass, nonspinning binary black holes. We urge the NR community to compute more sequences of scattering simulations, so as to extend this knowledge to a wider region of parameter space.

Recent investigations of the pseudospectrum in black hole spacetimes have shown that quasinormal mode frequencies suffer from spectral instabilities. This phenomenon may severely affect gravitational-wave spectroscopy and limit precision tests of general relativity. We extend the pseudospectrum analysis to horizonless exotic compact objects that possess a reflective surface arbitrarily close to the Schwarzschild radius and find that their quasinormal modes also suffer from an overall spectral instability. Even though all the modes themselves decay monotonically, the pseudospectrum contours of equal resonance magnitude around the fundamental mode and the lowest overtones can cross the real axis into the unstable regime of the complex plane, unveiling the existence of nonmodal pseudoresonances. A pseudospectrum analysis further predicts that fluctuations to the system may destabilize the object when next to leading-order effects are considered, as the triggering of pseudoresonant growth can break the order expansion of black hole perturbation theory.

We analyze the phase transition in improved holographic QCD to obtain an estimate of the gravitational wave signal emitted in the confinement transition of a pure SU(3) Yang-Mills dark sector. We derive the effective action from holography and show that the energy budget and duration of the phase transition can be calculated with minor errors. These are used as input to obtain a prediction of the gravitational wave signal. To our knowledge, this is the first computation of the gravitational wave signal in a holographic model designated to match lattice data on the thermal properties of pure Yang-Mills.