The 100 most-cited articles in Physical review. D/Physical review. D., 2024

The summarizes much of particle physics and cosmology. Using data from previous editions, plus 2,717 new measurements from 869 papers, we list, evaluate, and average measured properties of gauge bosons and the recently discovered Higgs boson, leptons, quarks, mesons, and baryons. We summarize searches for hypothetical particles such as supersymmetric particles, heavy bosons, axions, dark photons, etc. Particle properties and search limits are listed in Summary Tables. We give numerous tables, figures, formulae, and reviews of topics such as Higgs Boson Physics, Supersymmetry, Grand Unified Theories, Neutrino Mixing, Dark Energy, Dark Matter, Cosmology, Particle Detectors, Colliders, Probability and Statistics. Most of the 120 reviews are updated, including many that are heavily revised. The is divided into two volumes. Volume 1 includes the Summary Tables and 97 review articles. Volume 2 consists of the Particle Listings and contains also 23 reviews that address specific aspects of the data presented in the Listings. The complete (both volumes) is published online on the website of…

GWTC-2.1 is a catalog of gravitational wave events from compact binary coalescences from the first half of the third observing run of Advanced LIGO and Advanced Virgo. It improves on GWTC-2, which covered the same period but with less refined analysis methods. GWTC-2.1 identifies 8 new events, all identified as sourced by binary black holes with one exception identified as a neutron star-black hole coalescence. These events expand significantly on the parameters characterizing the sources of observed gravitational-wave transients.

The most conservative interpretation of the nHz stochastic gravitational wave background (SGWB) discovered by NANOGrav and other pulsar timing array (PTA) collaborations is astrophysical, namely that it originates from supermassive black hole (SMBH) binaries. However, alternative cosmological models have been proposed, including cosmic strings, phase transitions, domain walls, primordial fluctuations, and ``audible'' axions. We perform a multimodel analysis (MMA) to compare how well these different hypotheses fit the NANOGrav data, both in isolation and in combination with SMBH binaries, and address the questions: Which interpretations fit the data best, and which are disfavored? We also discuss experimental signatures that can help discriminate between different sources of the PTA GW signal, including fluctuations in the signal strength between frequency bins, individual sources, and how the PTA signal extends to higher frequencies.

We nonparametrically reconstruct the late-time expansion history in light of the latest baryon acoustic oscillation (BAO) measurements from DESI combined with various type Ia supernovae (SNeIa) catalogs, using interpolation through piece-wise natural cubic splines, and a reconstruction procedure based on Gaussian processes (GPs). Applied to DESI BAO and PantheonPlus SNeIa data, both methods indicate that deviations from a reference $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ model in the $z\ensuremath{\lesssim}2$ unnormalized expansion rate $E(z)$ are constrained to be $\ensuremath{\lesssim}10%$, but also consistently identify two features in $E(z)$: a bump at $z\ensuremath{\sim}0.5$, and a depression at $z\ensuremath{\sim}0.9$, which cannot be simultaneously captured by a ${w}_{0}{w}_{a}\mathrm{CDM}$ fit. These features, which are stable against assumptions regarding spatial curvature, interpolation knots, and GP kernel, disappear if one adopts the older SDSS BAO measurements in place of DESI, and decrease in significance when replacing the PantheonPlus catalog with the Union3 and…

New constraints on the expansion rate of the Universe seem to favor evolving dark energy in the form of thawing quintessence models, i.e., models for which a canonical, minimally coupled scalar field has, at late times, begun to evolve away from potential energy domination. We scrutinize the evidence for thawing quintessence by exploring what it predicts for the equation of state. We show that, in terms of the usual Chevalier-Polarski-Linder parameters, ( w 0 , w a ), thawing quintessence is, in fact, only marginally consistent with a compilation of the current data. Despite this, we embrace the possibility that thawing quintessence is dark energy and find constraints on the microphysics of this scenario. We do so in terms of the effective mass m 2 and energy scale V 0 of the scalar field potential. We are particularly careful to enforce uninformative, flat priors on these parameters so as to minimize their effect on the final posteriors. While the current data favors a large and negative value of m 2 , when we compare these models to the standard Λ CDM model we find that there is…

Hadron wave packets are prepared and time evolved in the Schwinger model using 112 qubits of IBM's 133-qubit Heron quantum computer ibm_torino. The initialization of the hadron wave packet is performed in two steps. First, the vacuum is prepared across the whole lattice using the recently developed SC-ADAPT-VQE algorithm and workflow. SC-ADAPT-VQE is then extended to the preparation of localized states, and used to establish a hadron wave packet on top of the vacuum. This is done by adaptively constructing low-depth circuits that maximize the overlap with an adiabatically prepared hadron wave packet. Due to the localized nature of the wavepacket, these circuits can be determined on a sequence of small lattices using classical computers, and then robustly scaled to prepare wave packets on large lattices for simulations using quantum computers. Time evolution is implemented with a second-order Trotterization. To reduce both the required qubit connectivity and circuit depth, an approximate quasilocal interaction is introduced. This approximation is made possible by the emergence of…

The recent result of the Dark Energy Spectroscopic Instrument (DESI) in combination with other cosmological data shows evidence of the evolving dark energy parametrized by the ${w}_{0}{w}_{a}\mathrm{CDM}$ model. We interpret this result in terms of a quintessential scalar field and demonstrate that it can explain the DESI result even though it becomes eventually phantom in the past. Relaxing the assumption on the functional form of the equation-of-state parameter $w=w(a)$, we also discuss a more realistic quintessential model. The implications of the DESI result for Swampland conjectures, cosmic birefringence, and the fate of the Universe are discussed as well.

The Schwarzschild geometry is investigated within the context of effective field theory models of gravity. Starting from its harmonic-coordinate expression, we derive the metric in standard coordinates by keeping the leading one-loop quantum contributions in their most general form. We examine the metric horizons and the nature of the hypersurfaces having constant radius; furthermore, a possible energy-extraction process that violates the null energy condition is described, and both timelike and null geodesics are studied. Our analysis shows that there is no choice of the sign of the constant parameter embodying the quantum correction to the metric which leaves all the features of the classical Schwarzschild solution almost unaffected.

We use a combination of Planck cosmic microwave background (CMB) anisotropy data and non-CMB data that include $\mathrm{Pantheon}+\text{type}$ Ia supernovae (SNIa), Hubble parameter [$H(z)$], growth factor ($f{\ensuremath{\sigma}}_{8}$) measurements, and a collection of baryon acoustic oscillation (BAO) data, but not recent DESI 2024 BAO measurements, to confirm the DESI 2024 ($\mathrm{DESI}+\mathrm{CMB}+\mathrm{PantheonPlus}$) data compilation support for dynamical dark energy with an evolving equation of state parameter $w(z)={w}_{0}+{w}_{a}z/(1+z)$. From our joint compilation of CMB and non-CMB data, in a spatially-flat cosmological model, we obtain ${w}_{0}=\ensuremath{-}0.850\ifmmode\pm\else\textpm\fi{}0.059$ and ${w}_{a}=\ensuremath{-}0.5{9}_{\ensuremath{-}0.22}^{+0.26}$ and find that this dynamical dark energy is favored over a cosmological constant by $\ensuremath{\sim}2\ensuremath{\sigma}$. Our data constraints on the flat ${w}_{0}{w}_{a}\mathrm{CDM}$ parametrization are slightly more restrictive than the DESI 2024 constraints, with the DESI 2024 and our values of ${w}_{0}$…

The cross section of the process e + e − → π + π − has been measured in the center of mass energy range from 0.32 to 1.2 GeV with the CMD-3 detector at the electron-positron collider VEPP-2000. The measurement is based on a full dataset collected below 1 GeV during three data taking seasons, corresponding to an integrated luminosity of about 62 pb − 1 . In the dominant ρ -resonance region, a systematic uncertainty of 0.7% has been reached. At energies around ϕ -resonance the π + π − production cross section was measured for the first time with high beam energy resolution. The forward-backward charge asymmetry in the π + π − production has also been measured. It shows a strong deviation from the theoretical prediction based on the conventional scalar quantum electrodynamics framework, and it is in good agreement with the generalized vector-meson-dominance and dispersive-based predictions. The impact of the presented results on the evaluation of the hadronic contribution to the anomalous magnetic moment of muon is discussed. Published by the American Physical Society 2024

We investigate a Schwarzschild metric exhibiting a signature change across the event horizon, which gives rise to what we term a Lorentzian-Euclidean black hole. The resulting geometry is regularized by employing the Hadamard partie finie technique, which allows us to prove that the metric represents a solution of vacuum Einstein equations. In this framework, we introduce the concept of atemporality as the dynamical mechanism responsible for the transition from a regime with a real-valued time variable to a new one featuring an imaginary time. We show that this mechanism prevents the occurrence of the singularity and, by means of the regularized Kretschmann invariant, we discuss in which terms atemporality can be considered as the characteristic feature of this black hole.

The recently released data by pulsar timing array (PTA) collaborations present strong evidence for a stochastic signal consistent with a gravitational-wave background. Assuming this signal originates from scalar-induced gravitational waves, we jointly use the PTA data from the NANOGrav 15-yr dataset, PPTA DR3, and EPTA DR2 to probe the small-scale non-Gaussianity. We put the first-ever constraint on the non-Gaussianity parameter, finding $|{F}_{\mathrm{NL}}|\ensuremath{\lesssim}13.9$ for a lognormal power spectrum of the curvature perturbations. Furthermore, we obtain $\ensuremath{-}13.9\ensuremath{\lesssim}{F}_{\mathrm{NL}}\ensuremath{\lesssim}\ensuremath{-}0.1$ to prevent excessive production of primordial black holes. Moreover, the multiband observations with the space-borne gravitational-wave detectors, such as LISA/Taiji/TianQin, will provide a complementary investigation of primordial non-Gaussianity. Our findings pave the way to constrain inflation models with PTAs.

We search for the rare decay B + → K + ν ν ¯ in a 362 fb − 1 sample of electron-positron collisions at the ϒ ( 4 S ) resonance collected with the Belle II detector at the SuperKEKB collider. We use the inclusive properties of the accompanying B meson in ϒ ( 4 S ) → B B ¯ events to suppress background from other decays of the signal B candidate and light-quark pair production. We validate the measurement with an auxiliary analysis based on a conventional hadronic reconstruction of the accompanying B meson. For background suppression, we exploit distinct signal features using machine learning methods tuned with simulated data. The signal-reconstruction efficiency and background suppression are validated through various control channels. The branching fraction is extracted in a maximum likelihood fit. Our inclusive and hadronic analyses yield consistent results for the B + → K + ν ν ¯ branching fraction of [ 2.7 ± 0.5 ( stat ) ± 0.5 ( syst ) ] × 10 − 5 and [ 1.1 − 0.8 + 0.9 ( stat ) − 0.5 + 0.8 ( syst ) ] × 10 − 5 , respectively. Combining the results, we determine the branching…

In general relativity, when two black holes merge they produce a rotating (Kerr) black hole remnant. According to perturbation theory, the remnant emits ``ringdown'' radiation; a superposition of exponentials with characteristic complex frequencies that depend only on the remnant's mass and spin. While the goal of the black hole spectroscopy program is to measure the quasinormal mode frequencies, a knowledge of their amplitudes and phases is equally important to determine which modes are detectable, and possibly to perform additional consistency checks. Unlike the complex frequencies, the amplitudes and phases depend on the properties of the binary progenitors, such as the binary mass ratio and component spins. In this paper we develop a fitting algorithm designed to reliably identify the modes present in numerical simulations and to extract their amplitudes and phases. We apply the algorithm to over 500 binary black hole simulations from the public SXS numerical relativity simulation catalog, and we present fitting formulas for the resulting mode amplitudes and phases as functions…

The NANOGrav and other pulsar timing arrays (PTAs) have recently announced evidence for nHz gravitational waves (GWs) that may originate from supermassive black hole (SMBH) binaries. The spectral index of the GW signal differs from that predicted for binary evolution by GW emission alone, and we show that environmental effects such as dynamical friction with gas, stars, and dark matter improve the consistency of the SMBH binary model with the PTA data. We comment on the possible implications of environmental effects for PTA observations of fluctuations in the GW frequency spectrum and measurements of GWs at higher frequencies.

This study introduces novel constraints on the free streaming of thermal relic warm dark matter (WDM) from Lyman- α forest flux power spectra. Our analysis utilizes a high resolution, high redshift sample of quasar spectra observed using the HIRES and UVES spectrographs ( z = 4.2 – 5.0 ). We employ a Bayesian inference framework and a simulation-based likelihood that encompasses various parameters including the free streaming of dark matter, cosmological parameters, the thermal history of the intergalactic medium, and inhomogeneous reionization to establish lower limits on the mass of a thermal relic WDM particle of 5.7 keV (at 95% CL). This result surpasses previous limits from the Lyman- α forest through reduction of the measured uncertainties due to a larger statistical sample and by measuring clustering to smaller scales ( k max = 0.2 km − 1 s ). The approximately two-fold improvement due to the expanded statistical sample suggests that the effectiveness of Lyman- α forest constraints on WDM models at high redshifts are limited by the availability of high quality quasar spectra.…

In this work we introduce phenomxo4a, the first phenomenological, frequency-domain gravitational waveform model to incorporate multipole asymmetries and precession angles tuned to numerical relativity. We build upon the modeling work that produced the phenompnr model and incorporate our additions into the imrphenomx framework, retuning the coprecessing frame model and extending the tuned precession angles to higher signal multipoles. We also include, for the first time in frequency-domain models, a recent model for spin-precession-induced multipolar asymmetry in the coprecessing frame to the dominant gravitational-wave multipoles. The accuracy of the full model and its constituent components is assessed through comparison to numerical relativity and numerical relativity surrogate waveforms by computing mismatches and performing parameter estimation studies. We show that, for the dominant signal multipole, we retain the modeling improvements seen in the phenompnr model. We find that the relative accuracy of current full IMR models varies depending on location in parameter space and…

The DESI Collaboration have recently analyzed their first year of data, finding a preference for thawing dark energy scenarios when using parametrized equations of state for dark energy. We investigate whether this preference persists when the data are analyzed within the context of a well-studied field theory model of thawing dark energy, exponential quintessence. No preference for this model over Lambda cold dark matter is found, and both models are poorer fits to the data than the Chevallier-Polarski-Linder ${w}_{0}\text{\ensuremath{-}}{w}_{a}$ parametrization. We demonstrate that the worse fit is due to a lack of sharp features in the potential that results in a slowly evolving dark energy equation of state that does not have enough freedom to simultaneously fit the combination of the supernovae, DESI, and cosmic microwave background data. Our analysis provides guidance for constructing dynamical dark energy models that are able to better accommodate the data.

In these two papers, the authors use mock maps to establish a method for studying the abundance and calibrating the weak-lensing based mass of galaxy clusters. They set up a likelihood function, thus obtaining cosmological constraints from a sample of 1,005 clusters detected with the South Pole Telescope, in combination with further cluster data from the Dark Energy Survey, the Wide-field Infrared Survey Explorer, and the Hubble Space Telescope.

The essence of the memory burden effect is that a load of information carried by a system stabilizes it. This universal effect is especially prominent in systems with a high capacity of information storage, such as black holes and other objects with maximal microstate degeneracy, the entities universally referred to as “saturons.” The phenomenon has several implications. The memory burden effect suppresses a further decay of a black hole, the latest, after it has emitted about half of its initial mass. As a consequence, the light primordial black holes that previously were assumed to be fully evaporated are expected to be present as viable dark matter candidates. In the present paper, we deepen the understanding of the memory burden effect. We first identify various memory burden regimes in generic Hamiltonian systems and then establish a precise correspondence in solitons and in black holes. We make transparent, at a microscopic level, the fundamental differences between the stabilization by a quantum memory burden versus the stabilization by a long-range classical hair due to a…

Primordial black holes can be formed from the collapse of large-amplitude perturbation on small scales in the early Universe. Such an enhanced spectrum can be realized by introducing a flat region in the potential of single-field inflation, which makes the inflaton go into a temporary ultraslow-roll period. In this paper, we calculate the bispectrum of curvature perturbation in such a scenario. We explicitly confirm that bispectrum satisfies Maldacena’s theorem. At the end of the ultraslow-roll period, the bispectrum is generated by bulk interaction and field redefinition. At the end of inflation, bispectrum is generated only by bulk interaction. We also calculate the one-loop correction to the power spectrum from the bispectrum, called the source method. We find it consistent with the calculation of the one-loop correction from the second-order expansion of in-in perturbation theory. Published by the American Physical Society 2024

Multiple pulsar timing array (PTA) collaborations recently announced the evidence of common-spectral processes caused by gravitational waves (GWs). These can be the stochastic GW background and its origin may be astrophysical and/or cosmological. We interpret it as the GWs induced by the primordial curvature perturbations and discuss their implications on primordial black holes (PBHs). We show that the newly released data suggest PBHs much lighter than the Sun [$\mathcal{O}({10}^{\ensuremath{-}4}){M}_{\ensuremath{\bigodot}}$ for the delta-function curvature spectrum; $<\mathcal{O}({10}^{\ensuremath{-}2}){M}_{\ensuremath{\bigodot}}$ more generally] in contrast to what was expected from the previous PTA data releases.

Cosmological first-order phase transitions (1stOPTs) are said to be strongly supercooled when the nucleation temperature is much smaller than the critical temperature. These are often encountered in theories that admit a nearly scale-invariant potential, for which the bounce action decreases only logarithmically with temperature. During supercooled 1stOPTs the equation of state of the universe undergoes a rapid and drastic change, transitioning from vacuum domination to radiation domination. The statistical variations in bubble nucleation histories imply that distinct causal patches percolate at slightly different times. Patches which percolate the latest undergo the longest vacuum-domination stage and as a consequence develop large overdensities triggering their collapse into primordial black holes (PBHs). We derive an analytical approximation for the probability of a patch to collapse into a PBH as a function of the 1stOPT duration, β−1 , and deduce the expected PBH abundance. We find that 1stOPTs which take more than 15% of a Hubble time to complete ( β/H≲7 ) produce observable…

The maximal gravitational mass of nonrotating neutron stars (${M}_{\mathrm{TOV}}$) is one of the key parameters of compact objects and only loose bounds can be set based on the first principle. With reliable measurements of the masses and/or radii of the neutron stars, ${M}_{\mathrm{TOV}}$ can be robustly inferred from either the mass distribution of these objects or the reconstruction of the equation of state of the very dense matter. For the first time we take the advantages of both two approaches to have a precise inference of ${M}_{\mathrm{TOV}}=2.2{5}_{\ensuremath{-}0.07}^{+0.08}{M}_{\ensuremath{\bigodot}}$ (68.3% credibility), with the updated neutron star mass measurement sample, the mass-tidal deformability data of GW170817, the mass-radius data of PSR $\mathrm{J}0030+0451$ and PSR $\mathrm{J}0740+6620$, as well as the theoretical information from the chiral effective theory and perturbative quantum chromodynamics (pQCD) at low- and very high-energy densities, respectively. This narrow credible range is benefited from the suppression of the high ${M}_{\mathrm{TOV}}$ by the…

In this study, we use simple performance metrics to assess the science capabilities of future ground-based gravitational-wave detector networks composed of $\mathrm{A}+$ or Voyager upgrades to the LIGO, Virgo, and KAGRA observatories and proposed next generation observatories such as Cosmic Explorer and Einstein Telescope. These metrics refer to coalescences of binary neutron stars (BNSs) and binary black holes (BBHs) and include; (i) network detection efficiency and detection rate of cosmological sources as a function of redshift, (ii) signal-to-noise ratios and the accuracy with which intrinsic and extrinsic parameters would be measured, and (iii) enabling multimessenger astronomy with gravitational waves by accurate 3D localization and early warning alerts. We further discuss the science enabled by the small population of rare and extremely loud events. While imminent upgrades will provide impressive advances in all these metrics, next generation observatories will deliver an improvement of an order-of-magnitude or more in most metrics. In fact, a network containing two or three…

The mass ranges allowed for primordial black holes (PBHs) to constitute all of dark matter (DM) are broadly constrained. However, these constraints rely on the standard semiclassical approximation which assumes that the evaporation process is self-similar. Quantum effects such as memory burden take the evaporation process out of the semiclassical regime latest by the time the black hole loses half of its mass. What happens beyond this time is currently not known. However, theoretical evidence based on prototype models indicates that the evaporation slows down, thereby extending the lifetime of a black hole. This modifies the mass ranges constrained, in particular, by big bang nucleosynthesis (BBN) and cosmic microwave background spectral distortions. We show that previous constraints are largely relaxed when the PBH lifetime is extended, making it possible for PBHs to constitute all of DM in previously excluded mass ranges. In particular, this is the case for PBHs lighter than 10 9 g that enter the memory burden stage before BBN and are still present today as DM. Published by the…

This paper introduces the class of omnipotent dark energy (DE) models characterized by nonmonotonic energy densities that are capable of attaining negative values with corresponding equation of state parameters featuring phantom divide line (PDL) crossings and singularities. These nontrivial features are phenomenologically motivated by findings of previous studies that reconstruct cosmological functions from observations, and the success of extensions of $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$, whose actual or effective DE density is omnipotent, in alleviating the observational discordance within $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$. As an example, we focus on one embodiment of omnipotent DE, viz. the DE parametrization introduced in Di Valentino et al. [Dark energy with phantom crossing and the ${H}_{0}$ tension, Entropy 23, 404 (2021)] (DMS20). By updating and extending the datasets used in the original paper where it was introduced, we confirm the effectiveness of DMS20 in alleviating the observational discrepancies. Additionally, we uncover that its negative DE…

Recently massless test scalar field perturbations of the holonomy corrected black holes [Z. Moreira et. al. Phys. Rev. D 107 (2023) 10, 104016] were studied in order to estimate quantum corrections to the quasinormal spectrum of a black hole. Here we study both the fundamental mode and overtones of scalar, electromagnetic and Dirac fields with the help of the Leaver method and higher order WKB formula with Pad\'e approximants. We observe that the overtones depend on the geometry near the event horizon, while the fundamental mode is localized near the peak of the potential barrier, what agrees with previous studies. We showed that unlike a massless field, the massive one possesses arbitrarily long lived modes. We also obtain the analytical eikonal formula for quasinormal modes and its extension beyond eikonal approximation as a series in powers of $1/\ell$, where $\ell$ is the multipole number.

We discuss the issue of perturbativity in single-field inflationary models with a phase of ultraslow-roll (USR) tailor suited to generate an order-one abundance of primordial black holes (PBHs). More in detail, we impose the condition that loop corrections made up of short-wavelength modes enhanced by the USR dynamics do not alter the tree-level power spectrum of curvature perturbations. In our analysis, the USR phase is preceded and followed by two stages of ordinary slow-roll (SR), and we model the resulting SR/USR/SR dynamics using both instantaneous and smooth transitions. Focusing on scales relevant for cosmic microwave background observations, we find that it is not possible, with these arguments, to rule out the scenario of PBH formation via USR, not even in the limit of instantaneous transition. However, we also find that loop corrections of short modes on the power spectrum of long modes, even though not large enough to violate perturbativity requirements, remain appreciable and, most importantly, are not tamed in realistic realizations of smooth SR/USR/SR transitions. This…

We present a novel study of Kerr Compton amplitudes in a partial wave basis in terms of the Nekrasov-Shatashvili (NS) function of the confluent Heun equation (CHE). Remarkably, NS-functions enjoy analytic properties and symmetries that are naturally inherited by the Compton amplitudes. Based on this, we characterize the analytic dependence of the Compton phase shift in the Kerr spin parameter and provide a direct comparison to the standard post-Minkowskian (PM) perturbative approach within general relativity (GR). We also analyze the universal large frequency behavior of the relevant characteristic exponent of the CHE—also known as the renormalized angular momentum—and find agreement with numerical computations. Moreover, we discuss the analytic continuation in the harmonics quantum number ℓ of the partial wave, and show that the limit to the physical integer values commutes with the PM expansion of the observables. Finally, we obtain the contributions to the tree-level, point-particle, gravitational Compton amplitude in a covariant basis through O(aBH8) , without the need to take…

Axionlike particles (ALPs) coupled to nucleons might be copiously emitted from a supernova (SN) core. We extend existing bounds on free-streaming ALPs to the case in which these are so strongly interacting with the nuclear matter to be trapped in the SN core. For strongly interacting ALPs, we also extend the bound from the absence of an ALP-induced signal in Kamiokande-II neutrino detector at the time of SN 1987A. We find that combining the different arguments, SNe exclude values of ALP-nucleon coupling gaN≳10−9 for ALP masses ma≲1 MeV . Remarkably, in the case of canonical QCD axion models, the SN bounds exclude all values of ma≳10−2 eV . This result prevents the possibility for current and future cosmological surveys to detect any signatures due to hot dark matter QCD axion mass. Published by the American Physical Society 2024

We explore the presence of self-interacting bosonic dark matter (DM) within neutron stars (NSs) in light of the latest multimessenger observations of the Neutron Star Interior Composition Explorer (NICER) and LIGO/Virgo detectors. The bosonic DM is distributed as a core inside the NS or as a halo around it leading to formation of a DM admixed NS. We focus on the variation of the visible and dark radius of the mixed object due to DM model parameters and fractions. It is shown that DM core formation reduces the visible radius and the total mass pushing them below observational limits while halo formation is in favor of the latest mass-radius observations. Moreover, we scan over the parameter space of the bosonic DM model considering two nuclear matter equation of states by applying the radius, maximum mass and tidal deformability constraints. Our investigation allows for the exclusion of a range of DM fractions, self-coupling constant and sub-GeV boson masses, which limits the amount of accumulated DM to relatively low values to be consistent with astrophysical bounds. In this paper,…

The Milky Way dwarf spheroidal satellite galaxies (dSphs) are particularly intriguing targets to search for gamma rays from weakly interacting massive particle dark matter (DM) annihilation or decay. They are nearby, DM-dominated, and lack significant emission from standard astrophysical processes. Previous studies using the Fermi-Large Area Telescope (LAT) of DM-induced emission from dSphs have provided the most robust and stringent constraints on the DM annihilation cross section and mass. We report here an analysis of the Milky Way dSphs using over 14 years of LAT data along with an updated census of dSphs and $J$-factor estimates. While no individual dSphs are significantly detected, we do find slight excesses with respect to background at the $\ensuremath{\gtrsim}2\ensuremath{\sigma}$ local significance level in both tested annihilation channels ($b\overline{b}$, ${\ensuremath{\tau}}^{+}{\ensuremath{\tau}}^{\ensuremath{-}}$) for seven of the dSphs. We do not find a significant DM signal from the combined likelihood analysis of the dSphs…

The quasinormal mode spectrum of black holes plays a crucial role in the modeling of postmerger ringdown signals. However, the spectrum is extremely sensitive to small deformations of the system and describes the linear response only in a certain (not precisely defined) time frame after the merger. We argue here that the graybody factors, recently shown to describe the ringdown spectral amplitude at relatively high frequencies, are instead stable under small perturbations of the system and free of certain ambiguities that plague the quasinormal mode spectrum. Our analysis also unveils a nontrivial interplay: While certain ringdown quantities are dominated by the contribution of spectrally unstable quasinormal modes, these modes conspire to produce stable observables. Thus, we propose a complementary approach to ringdown studies, which circumvents some limitations of the standard quasinormal mode description.

A measurement of the diffuse astrophysical neutrino spectrum is presented using IceCube data collected from 2011--2022 (10.3 years). We developed novel detection techniques to search for events with a contained vertex and exiting track induced by muon neutrinos undergoing a charged-current interaction. Searching for these starting track events allows us to not only more effectively reject atmospheric muons but also atmospheric neutrino backgrounds in the southern sky, opening a new window to the sub-100 TeV astrophysical neutrino sky. The event selection is constructed using a dynamic starting track veto and machine learning algorithms. We use this data to measure the astrophysical diffuse flux as a single power law flux (SPL) with a best-fit spectral index of $\ensuremath{\gamma}=2.5{8}_{\ensuremath{-}0.09}^{+0.10}$ and per-flavor normalization of ${\ensuremath{\phi}}_{\mathrm{per}\text{-flavor}}^{\text{Astro}}=1.6{8}_{\ensuremath{-}0.22}^{+0.19}\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}18}\ifmmode\times\else\texttimes\fi{}{\mathrm{GeV}}^{\ensuremath{-}1}\text{…

Observations of the millimeter sky contain valuable information on a number of signals, including the blackbody cosmic microwave background (CMB), Galactic emissions, and the Compton-$y$ distortion due to the thermal Sunyaev-Zel'dovich (tSZ) effect. Extracting new insight into cosmological and astrophysical questions often requires combining multiwavelength observations to spectrally isolate one component. In this work, we present a new arc-minute-resolution Compton-$y$ map, which traces out the line-of-sight-integrated electron pressure, as well as maps of the CMB in intensity and E-mode polarization, across a third of the sky (around $13,000\text{ }\text{ }{\mathrm{deg}}^{2}$). We produce these through a joint analysis of data from the Atacama Cosmology Telescope (ACT) data release 4 and 6 at frequencies of roughly 93, 148, and 225 GHz, together with data from the Planck satellite at frequencies between 30 and 545 GHz. We present detailed verification of an internal linear combination pipeline implemented in a needlet frame that allows us to efficiently suppress Galactic…

Cosmological neutrino mass bounds are becoming increasingly stringent. The latest limit within Λ CDM from Planck 2018 + ACT lensing + DESI is ∑ m ν < 0.072 eV at 95% CL, very close to the minimum possible sum of neutrino masses ( ∑ m ν > 0.06 eV ), hinting at vanishing or even “negative” cosmological neutrino masses. In this context, it is urgent to carefully evaluate the origin of these cosmological constraints. In this paper, we investigate the robustness of these results in three ways: (i) we check the role of potential anomalies in Planck CMB and DESI BAO data; (ii) we compare the results for frequentist and Bayesian techniques, as very close to physical boundaries subtleties in the derivation and interpretation of constraints can arise; (iii) we investigate how deviations from Λ CDM , potentially alleviating these anomalies, can alter the constraints. From a profile likelihood analysis, we derive constraints in agreement at the ∼ 10 % level with Bayesian posteriors. We find that the weak preference for negative neutrino masses is mostly present for Planck 18 data, affected by…

It is shown that the spectral amplitude of gravitational wave ringdown of a Kerr black hole sourced by an extreme mass ratio merger can be modeled by the greybody factor, which quantifies the scattering nature of the black hole geometry. The estimation of the mass and spin of the remnant is demonstrated by fitting the greybody factor to gravitational wave data without using black hole quasinormal modes. We propose that the ringdown modeling with the greybody factor may strengthen the test of gravity as one can avoid the possible overfitting issue and the start time problem in the ringdown modeling with superposed quasinormal modes.

We show that the recent detection of a gravitational wave (GW) background reported by various pulsar timing array (PTA) collaborations including NANOGrav-15 yr, PPTA, EPTA/InPTA, and CPTA can be explained in terms of first order phase transitions (FOPTs) from dark sector models (DSM). Specifically, we explore a model for first order phase transitions that involves the Majoron, a Nambu-Goldstone boson that is emerging from the spontaneous symmetry breaking of a $U(1{)}_{L}$ or $U(1{)}_{B\ensuremath{-}L}$ symmetry. We show how the predicted GW power spectrum, with a realistic choice of the FOPT parameters, is consistent with $1\text{\ensuremath{-}}\ensuremath{\sigma}$ deviations from the estimated parameters of the background detected by the PTA collaborations.

The Dark Energy Spectroscopic Instrument (DESI) collaboration has recently released measurements of baryon acoustic oscillation (BAO) from the first year of observations. A joint analysis of DESI BAO, cosmic microwave background (CMB), and Type Ia supernovae (SNe Ia) probes indicates a preference for time-evolving dark energy. We evaluate the robustness of this preference by replacing the DESI distance measurements at $z<0.8$ with the Sloan Digital Sky Survey (SDSS) BAO measurements in a similar redshift range. Assuming the ${w}_{0}{w}_{a}\mathrm{CDM}$ model, we find an evolution of the dark energy equation of state parameters consistent with $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$. Our analysis of ${\ensuremath{\chi}}^{2}$ statistics across various BAO datasets shows that DESI's preference for evolving dark energy is primarily driven by the two luminous red galaxy (LRG) samples at ${z}_{\mathrm{eff}}=0.51$ and ${z}_{\mathrm{eff}}=0.71$, with the latter having the most significant impact. Taking this preference seriously, we study a general Horndeski scalar-tensor theory, which…

In this Letter, we investigate the universal classifications of black hole states by considering them as topological defects within the thermodynamic parameter space. Through the asymptotic behaviors of the constructed vector, our results indicate the existence of four distinct topological classifications, denoted as ${W}^{1\ensuremath{-}}$, ${W}^{0+}$, ${W}^{0\ensuremath{-}}$, and ${W}^{1+}$. Within these classifications, the innermost small black hole states are characterized as unstable, stable, unstable, and stable, respectively, while the outermost large ones exhibit an unstable, unstable, stable, and stable behavior. These classifications also display contrasting thermodynamic properties in both low and high Hawking temperature limits. Furthermore, we establish a systematic ordering of the local thermodynamically stable and unstable black hole states as the horizon radius increases for a specific topological classification. These results reveal the universal topological classifications governing black hole thermodynamics, providing valuable insights into the fundamental nature…

A fundamental question in quantum chromodynamics (QCD) is the existence of a phase transition at large doping of quarks over antiquarks. We present the first prediction of a QCD critical point ($CP$) from a Bayesian analysis constrained by first principle results at zero doping. We employ the gauge/gravity duality to map QCD onto a theory of dual black holes. Predictions for the $CP$ location in different realizations of the model overlap at one sigma. Even if many prior samples do not include a $CP$, one is found in nearly 100% of posterior samples, indicating a strong preference for a $CP$.

We present an updated version of the teobresums-dal\'{\i} effective one body (EOB) waveform model for spin-aligned binaries on noncircularized orbits. Recently computed 4 Post Newtonian (PN) (nonspinning) terms are incorporated in the waveform and radiation reaction. The model is informed by a restricted sample ($\ensuremath{\sim}60$) of spin-aligned, quasicircular, numerical relativity (NR) simulations. In the quasicircular limit, the model displays EOB/NR maximal unfaithfulness ${\overline{\mathcal{F}}}_{\mathrm{EOBNR}}^{\mathrm{max}}\ensuremath{\lesssim}{10}^{\ensuremath{-}2}$ (with median $1.06\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$) (with Advanced LIGO noise and in the total mass range $10--200{M}_{\ensuremath{\bigodot}}$) for the dominant $\ensuremath{\ell}=m=2$ mode all over the 534 spin-aligned configurations available through the simulating extreme spacetime catalog of NR waveforms. Similar figures are also obtained with the 28 public eccentric simulating extreme spacetime simulations as well as good compatibility between EOB and NR scattering angles. The…

The Large Hadron Collider provides a unique opportunity to study quantum entanglement and violation of Bell inequalities at the highest energy available today. In this paper, we will investigate these quantum correlations with top quark pair production, which represents a system of two-qubits. The semileptonic top pair channel has a factor of 6 increase in statistics and easier reconstruction with respect to the dileptonic channel. Although measuring the spin polarization of the hadronic top quark is known to be challenging, our study indicates that it is feasible to reconstruct the spin density matrix of the two-qubit system using an optimal hadronic polarimeter. This is achieved with the aid of jet substructure techniques and NN-inspired reconstruction methods, which improve the mapping between subjets and quarks. We find that entanglement can already be observed at more than the 5 σ level with existing data, and violation of Bell inequalities may be probed above the 4 σ level at the HL-LHC with 3 ab − 1 of data. Published by the American Physical Society 2024

In recent years, cosmic microwave background (CMB) observations, weak lensing surveys, and $f{\ensuremath{\sigma}}_{8}(z)$ measurements from redshift-space distortions (RSD) have revealed a significant ($\ensuremath{\sim}3--5\ensuremath{\sigma}$) discrepancy in the inferred value of the matter clustering parameter ${S}_{8}$. In this work, we investigate the implications of RSD for a cosmological framework postulating an interaction between dark energy (DE) and dark matter (DM). We explore scenarios where DM can transfer energy momentum to DE or vice versa. The energy-momentum flow is characterized by the strength and the sign of the coupling parameter $\ensuremath{\xi}$. Our baseline analysis combines RSD measurements with the latest data from baryon acoustic oscillations (BAO) observed by DESI, type Ia supernovae from the PantheonPlus sample, and CMB data from Planck. We demonstrate that RSD measurements provide significant additional information imposing new and strong upper bounds on possible interaction in the dark sector. Models with $\ensuremath{\xi}>0$ can effectively…

In this work, we implement Gaussian process regression to reconstruct the expansion history of the Universe in a model-agnostic manner, using the Pantheon-Plus SN-Ia compilation in combination with two different BAO measurements (SDSS-IV and DESI DR1). In both the reconstructions, the $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ model is always included in the 95% confidence levels. We find evidence that the DESI LRG data at ${z}_{\mathrm{eff}}=0.51$ is not an outlier within our model-independent framework. We study the $\mathcal{O}m$ diagnostics and the evolution of the total equation of state (EOS) of our Universe, which hint toward the possibility of a quintessence-like dark energy scenario with a very slowly varying EOS and a phantom crossing in higher $z$. The entire exercise is later complemented by considering two more SN-Ia compilations---DES-5YR and Union3---in combination with DESI BAO. Reconstruction with the DESI BAO + DES-5YR SN datasets predicts that the $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ model lies outside the $3\ensuremath{\sigma}$ confidence intervals,…

Quintessence scalar fields are a natural candidate for evolving dark energy. Unlike the phenomenological ${w}_{0}{w}_{a}$ parameterization of the dark energy equation of state, they cannot accommodate the phantom regime of dark energy $w(z)<\ensuremath{-}1$, or crossings into the phantom regime. Recent baryon acoustic oscillation (BAO) measurements by the Dark Energy Spectroscopic Instrument (DESI) indicate a preference for evolving dark energy over a cosmological constant, ranging from $2.6\ensuremath{\sigma}\ensuremath{-}3.9\ensuremath{\sigma}$ when fitting to ${w}_{0}{w}_{a}$, and combining the DESI BAO measurements with other cosmological probes. In this work, we directly fit three simple scalar field models to the DESI BAO data, combined with cosmic microwave background anisotropy measurements and supernova datasets. We find the best fit model to include a 2--4% kinetic scalar field energy ${\mathrm{\ensuremath{\Omega}}}_{\mathrm{scf},\mathrm{k}}$, for a canonical scalar field with a quadratic or linear potential. However, only the DESY-Y5 supernova dataset combination shows a…

We match scattering amplitudes in point particle effective field theory (EFT) and general relativity to extract low frequency dynamical tidal responses of rotating (Kerr) black holes to all orders in spin. In the conservative sector, we study local worldline couplings that correspond to the time-derivative expansion of the black hole tidal response function. These are dynamical (frequency-dependent) generalizations of the static Love numbers. We identify and extract couplings of three types of subleading local worldline operators: the curvature time derivative terms, the spin-curvature time derivative couplings, and quadrupole-octupole mixing operators that arise due to the violation of spherical symmetry. The first two subleading couplings are nonzero and exhibit a classical renormalization group running; we explicitly present their scheme-independent beta functions. The conservative mixing terms, however, vanish as a consequence of vanishing static Love numbers. In the nonconservative sector, we match the dissipation numbers at next-to-leading and next-to-next-to leading orders in…

Rare decays mediated by b → s ν ν ¯ transitions have been reported by the Belle II experiment. The branching ratio of the decay B + → K + ν ν ¯ is found to be enhanced with respect to the standard model value. If taken at face value, the implications are profound; either lepton flavor universality is violated at the (multi)-TeV-scale, or light new physics is involved. This holds in general if B ( B + → K + ν ν ¯ ) exceeds 1.2 × 10 − 5 ( 1.3 × 10 − 5 ) at 1 σ ( 2 σ ), which tightens with a decreasing upper limit on B ( B → K * ν ν ¯ ) , that is in reach of the Belle II experiment. In view of the strong constraints on electron-muon universality violation in | Δ b | = | Δ s | = 1 processes, viable explanations are heavy, (5–10)-TeV tree-level new physics mediators that couple only to tau-flavors, or lepton flavor violating ones. In addition, couplings of similar size to both left- and right-handed quarks are generically required, implying nonminimal beyond the standard model sectors which are carefully balanced against flavor constraints. The decay B s 0 → invisibles can shed light on…

The Bardeen black hole stands as the first model of a regular black hole. Driven by the interpretations of Bardeen spacetime as a quantum-corrected Schwarzschild-like solution, we study quasinormal modes of a massive scalar field within this context. We have found that the damping rate of the massive scalar field decreases as the mass grows, leading to appearance of the arbitrarily long-lived modes. or quasiresonances. The massive term in the Bardeen case is also distinctive in two other respects. First, the overtones deviate from their massless limit at a much smaller rate than the fundamental mode, when the mass is turned on. This behavior overlaps with the so called outburst of overtones, which is deviation of overtones from their Schwarzschild values at an increasingly higher rate than happens for the fundamental mode. This high sensitivity of overtones occurs due to the quantum deformation near the event horizon. Finally, integration in the time domain shows that the oscillatory tails decay as $\ensuremath{\sim}{t}^{\ensuremath{-}(\frac{8}{6}+\ensuremath{\ell})}$ at…

The $\ensuremath{\sim}5\ensuremath{\sigma}$ mismatch between the value of the Hubble parameter measured by SH0ES and the one inferred from the inverse distance ladder (IDL) constitutes the biggest tension afflicting the standard model of cosmology, which could be pointing to the need of physics beyond $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$. In this paper, we study the background history required to solve the ${H}_{0}$ tension if we consider standard prerecombination physics, paying special attention to the role played by the data on baryon acoustic oscillations (BAO) employed to build the IDL. We show that the anisotropic BAO data favor an ultra-late-time (phantomlike) enhancement of $H(z)$ at $z\ensuremath{\lesssim}0.2$, accompanied by a transition in the absolute magnitude of supernovae of type Ia $M(z)$ in the same redshift range. This agrees with previous findings in the literature. The effective dark energy (DE) density must be smaller than in the standard model at higher redshifts. Instead, when angular BAO data (claimed to be less subject to model dependencies) is…

Eikonal quasinormal modes (QNMs) of black holes (BHs) and parameters of null geodesics, ultimately tied to the appearance of BHs to external observers, are known to be related, and the eikonal QNM-BH shadow radii correspondence has been extensively studied for spherically symmetric BHs. The extension to rotating BHs is nontrivial, and has been worked out only for equatorial ($m=\ifmmode\pm\else\textpm\fi{}\ensuremath{\ell}$) QNMs, or for general modes but limited to the Kerr metric. We extend the QNM-shadow radius correspondence to more general rotating space-times, and argue that the requirements for it to hold amount to conditions on the separability of the Hamilton-Jacobi equation for null geodesics and the Klein-Gordon equation. Metrics obtained by the Newman-Janis algorithm enjoy these conditions, provided certain mathematical requirements are imposed on the line element. We explicitly verify the correspondence for the rotating Bardeen and Hayward regular BHs, both of which satisfy the separability requirements. Our findings show that the QNM-shadow radius correspondence holds…

The excitation of quadratic quasinormal modes is an important nonlinear phenomenon for a Kerr black hole ringing at a specific linear mode. The amplitude of this second-order effect is proportional to the square of the linear mode amplitude, with the ratio being linked to the nature of the Kerr black hole. Focusing on the linear $(l=m=2,n=0)$ mode, we compute the dependency of the ratio on the dimensionless spin of the black hole, ranging up to 0.99, with the method applicable for more general mode couplings. Our calculation makes use of the frequency-domain, second-order Teukolsky equation, which involves two essential steps: (a) analytically reconstructing the metric through the Chrzanowski-Cohen-Kegeles approach and (b) numerically solving the second-order Teukolsky equation using the shooting method along a complex contour. We find that the spin dependence of the ratio shows a strong correlation with the angular overlap between parent and child modes, providing qualitative insights into the origin of the dependence. Depending on the nature of the angular overlap, the ratio…

For the analysis of gravitational-wave signals, fast and accurate gravitational-waveform models are required. These enable us to obtain information on the system properties from compact binary mergers. In this article, we introduce the model, which contains a closed-form expression that describes tidal effects, focusing on the description of binary neutron star systems. The model improves upon previous versions by employing a larger set of numerical-relativity data for its calibration, by including high-mass ratio systems covering also a wider range of equations of state. It also takes into account dynamical tidal effects and the known post-Newtonian mass-ratio dependence of individual calibration parameters. We implemented the model in the publicly available uite software library by augmenting different binary black hole waveform models (, , and ). We test the validity of by comparing it with numerical-relativity waveforms, as well as other tidal models. Finally, we perform parameter estimation for GW170817 and GW190425 with the new tidal approximant and find overall consistent…

We present an up-to-date compilation of published Hubble constant (${H}_{0}$) measurements that are independent of the cosmic microwave background sound horizon scale. This compilation is split in two distinct groups: A. Distance ladder measurements sample comprising of 20 recent measurements, primarily from the past four years, utilizing various rung 2 calibrators and rung 3 cosmic distance indicators. B. One-step measurements sample including 33 measurements of ${H}_{0}$ that are independent of both the cosmic microwave background sound horizon scale and the distance ladder approach. These 33 measurements are derived from diverse probes such as cosmic chronometers, gamma-ray attenuation, strong lensing, megamasers etc. Statistical analysis reveals a significant distinction between the two samples. The distance ladder-based sample yields a best fit ${H}_{0}=72.8\ifmmode\pm\else\textpm\fi{}0.5\text{ }\text{ }\mathrm{km}\text{ }{\mathrm{s}}^{\ensuremath{-}1}\text{ }{\mathrm{Mpc}}^{\ensuremath{-}1}$ with ${\ensuremath{\chi}}^{2}/\mathrm{d}.\mathrm{o}.\mathrm{f}.=0.51$ indicating some…

Primordial black hole (PBH) formation during cosmic phase transitions and annihilation periods, such as the QCD transition or the ${e}^{+}{e}^{\ensuremath{-}}$ annihilation, is thought to be particularly efficient due to a softening of the equation of state. We present a detailed numerical study of PBH formation during the QCD epoch in order to derive an accurate PBH mass function. We also briefly consider PBH formation during the ${e}^{+}{e}^{\ensuremath{-}}$-annihilation epoch. Our investigation confirms that, for nearly scale-invariant spectra, PBH abundances on the QCD scale are enhanced by a factor $\ensuremath{\sim}{10}^{3}$ compared to a purely radiation dominated Universe. For a power spectrum producing an (almost) scale-invariant PBH mass function outside of the transition, we find a peak mass of ${M}_{\mathrm{pbh}}\ensuremath{\approx}1.9{M}_{\ensuremath{\bigodot}}$ with a fraction $f\ensuremath{\approx}1.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}$ of the PBHs having a mass of ${M}_{\mathrm{pbh}}>10{M}_{\ensuremath{\bigodot}}$, possibly contributing to the…

The nonlinear character of general relativity leaves its imprint in the coalescence of two black holes, from the inspiral to the final ringdown stage. To quantify the impact of nonlinearities, we work at second order in black hole perturbation theory and we study the excitation of second-order modes relative to the first-order modes that drive them as we vary the black hole spin and the initial data for the perturbations. The relative amplitude of second-order modes is only mildly dependent on the initial data that we consider, but it strongly decreases for large black hole spins. This implies that the extrapolation of calculations based on the Kerr--conformal field theory correspondence to subextremal Kerr black holes should be viewed with caution.

We develop a numerical approach to compute polar parity perturbations within fully relativistic models of black hole systems embedded in generic, spherically symmetric, anisotropic fluids. We apply this framework to study gravitational wave generation and propagation from extreme mass-ratio inspirals in the presence of several astrophysically relevant dark matter models, namely the Hernquist, Navarro-Frenk-White, and Einasto profiles. We also study dark matter spike profiles obtained from a fully relativistic calculation of the adiabatic growth of a BH within the Hernquist profile, and provide a closed-form analytic fit of these profiles. Our analysis completes prior numerical work in the axial sector, yielding a fully numerical pipeline to study black hole environmental effects. We study the dependence of the fluxes on the DM halo mass and compactness. We find that, unlike the axial case, polar fluxes are not adequately described by simple gravitational-redshift effects, thus offering an exciting avenue for the study of black hole environments with gravitational waves.

We revisit a question asked by Dyson: “Is a graviton detectable?” We demonstrate that in both Dyson’s original sense and in a more modern measurement-theoretic sense, it is possible to construct a detector sensitive to single gravitons, and in fact a variety of existing and near-term gravitational wave detectors can achieve this. However, while such a signal would be consistent with the quantization of the gravitational field, we draw on results from quantum optics to show how the same signal could just as well be explained via classical gravitational waves. We outline the kind of measurements that would be needed to demonstrate quantization of gravitational radiation and explain why these are substantially more difficult than simply counting graviton clicks or observing gravitational noise in an interferometer, and likely impossible to perform in practice. Published by the American Physical Society 2024

We present details on a new measurement of the muon magnetic anomaly, a μ = ( g μ − 2 ) / 2 . The result is based on positive muon data taken at Fermilab’s Muon Campus during the 2019 and 2020 accelerator runs. The measurement uses 3.1 GeV / c polarized muons stored in a 7.1-m-radius storage ring with a 1.45 T uniform magnetic field. The value of a μ is determined from the measured difference between the muon spin precession frequency and its cyclotron frequency. This difference is normalized to the strength of the magnetic field, measured using nuclear magnetic resonance. The ratio is then corrected for small contributions from beam motion, beam dispersion, and transient magnetic fields. We measure a μ = 116 592 057 ( 25 ) × 10 − 11 (0.21 ppm). This is the world’s most precise measurement of this quantity and represents a factor of 2.2 improvement over our previous result based on the 2018 dataset. In combination, the two datasets yield a μ ( FNAL ) = 116 592 055 ( 24 ) × 10 − 11 (0.20 ppm). Combining this with the measurements from Brookhaven National Laboratory for both positive…

The ATLAS Collaboration has recently reported the results of a low-mass Higgs-boson search in the diphoton final state based on the full Run 2 dataset. The results are based on an improved analysis with respect to the previous analysis, which included a part of the Run 2 data, with a substantially better sensitivity. The “model-dependent” search carried out by ATLAS shows an excess of events at a mass of about 95.4 GeV with a local significance of 1.7σ . The results are compatible with a previously reported excess at the same mass, but with somewhat higher significance of 2.9σ , from the CMS collaboration, also based on the full Run 2 dataset. Combining the two results (neglecting possible correlations), we find a signal strength of μγγATLAS+CMS=0.24−0.08+0.09 , corresponding to an excess of 3.1σ . In this work, we investigate the implications of this result, updating a previous analysis based solely on the CMS Run 2 data. We demonstrate that the ATLAS/CMS combined diphoton excess can be interpreted as the lightest Higgs boson in a Two-Higgs doublet model that is extended by a…

Starting with on-shell amplitudes compatible with the scattering of Kerr black holes up to Compton-amplitude contact terms, we produce the gravitational waveform and memory effect including spin at their leading post-Minkowskian orders to all orders in the spins of both scattering objects. For the memory effect, we present results at next-to-leading order as well, finding a closed form for all spin orders when the spins are anti-aligned and equal in magnitude. Considering instead generically oriented spins, we produce the next-to-leading-order memory to sixth order in spin. Compton-amplitude contact terms up to sixth order in spin are included throughout our analysis. Published by the American Physical Society 2024

We present explicit black holes endowed with primary scalar hair within the shift-symmetric subclass of beyond Horndeski theories. These solutions depend, in addition to the conventional mass parameter, on a second free parameter encoding primary scalar hair. The properties and characteristics of the solutions at hand are analyzed with a varying scalar charge. We observe that when the scalar hair parameter is close to zero or relatively small in comparison to the black-hole mass, the solutions closely resemble the Schwarzschild spacetime. As the scalar hair increases, the metric solutions gradually depart from general relativity. Notably, for a particular relation between mass and scalar hair, the central singularity completely disappears, resulting in the formation of regular black holes or solitons. The scalar field accompanying the solutions is always found to be regular at future or past horizon(s), defining a distinct time direction for each. As a final by-product of our analysis, we demonstrate the existence of a stealth Schwarschild black hole in Horndeski theory with a…

We revisit the quantum-amplitude-based derivation of the gravitational waveform emitted by the scattering of two spinless massive bodies at the third order in Newton’s constant, h ∼ G + G 2 + G 3 (one-loop level), and correspondingly update its comparison with its classically derived multipolar-post-Minkowskian counterpart. A spurious-pole-free reorganization of the one-loop five-point amplitude substantially simplifies the post-Newtonian expansion. We find complete agreement between the two results up to the fifth order in the small velocity expansion after taking into account three subtle aspects of the amplitude derivation: (1) in agreement with [A. Georgoudis , ], the term quadratic in the amplitude in the observable-based formalism [D. A. Kosower , ] generates a frame rotation by half the classical scattering angle; (2) the dimensional regularization of the infrared divergences of the amplitude introduces an additional ( d − 4 ) / ( d − 4 ) finite term; and (3) zero-frequency gravitons are found to contribute additional terms both at order h ∼ G 1 and at order h ∼ G 3 when…

We present a feasibility study to probe quantum entanglement and Bell inequality violation in the process e+e−→τ+τ− at a center-of-mass energy of s=10.579 GeV . The sensitivity of the analysis is enhanced by applying a selection on the scattering angle ϑ in the τ+τ− center-of-mass frame. We analyze events in which both τ leptons decay to hadrons, using a combination of decay channels τ−→π−ντ , τ−→π−π0ντ , and τ−→π−π+π−ντ . The spin orientation of the τ leptons in these decays is reconstructed using the polarimeter-vector method. Assuming a dataset of 200 million τ+τ− events and accounting for experimental resolutions, we expect the observation of quantum entanglement and Bell inequality violation by the Belle-II experiment will be possible with a significance well in excess of five standard deviations. Published by the American Physical Society 2024

Black holes in anti--de Sitter spacetime provide an important testing ground for both gravitational and field-theoretic phenomena. In particular, the study of perturbations can be useful to further our understanding regarding certain physical processes, such as superradiance, or the dynamics of strongly coupled conformal field theories through the holographic principle. In this work we continue our systematic study of the ultraviolet instabilities of black-hole quasinormal modes, built on the characterization of the latter as eigenvalues of a (spectrally unstable) nonselfadjoint operator and using the pseudospectrum as a main analysis tool, extending our previous studies in the asymptotically flat setting to anti--de Sitter asymptotics. Very importantly, this step provides a singularly well-suited probe into some of the key structural aspects of the pseudospectrum. This is a consequence of the specific features of the Schwarzschild-anti-de Sitter geometry, together with the existence of a sound characterization by Warnick of quasinormal modes as eigenvalues, that is still absent in…

Recently, Bonanno et al. [Dust collapse in asymptotic safety: A path to regular black holes, Phys. Rev. Lett. 132, 031401 (2024)] presented an explicit metric describing the exterior of a collapsing dust ball within the framework of asymptotically safe gravity. Based on this metric, we investigate in detail the properties of the quasinormal mode (QNM) spectra for test massless scalar, vector, and Dirac fields. We find accurate values for the fundamental QNM frequency and the first overtones, demonstrating the appearance of a peculiar spiral-like behavior of the overtones compared to the fundamental modes. Additionally, we study black hole shadows and show that they align with Enstein Horizon Telescope observations. Finally, we study the gray-body factors and provide explicit lower bound estimates.

The gravitational waves emitted in the ringdown phase of binary black hole coalescence are a unique probe of strong gravity. At late times in the ringdown, these waves can be described by quasinormal modes, whose frequencies encode the mass and spin of the remnant, as well as the theory of gravity in play. Understanding precisely how deviations from general relativity affect the quasinormal mode frequencies of ringing black holes, however, is extremely challenging, as it requires solving highly coupled and sometimes higher-order partial differential equations. We here extend a novel approach, metric perturbations with spectral methods (METRICS), to study the gravitational metric perturbations and the quasinormal mode frequencies of ringing black holes in modified gravity. We first derive the asymptotic behavior of gravitational perturbations at the event horizon and spatial infinity for rotating black holes beyond general relativity. We then extend the eigenvalue-perturbation theory approach of METRICS to allow us to compute the leading-order beyond general relativity corrections to…

Primordial black holes are one possible formation channel for the binary black holes observed by LIGO-Virgo-Kagra. The authors perform a data analysis of the O3 events to infer stringent constraint on the primordial black hole abundance in a wide mass range. Furthermore, they show that this result is robust with respect to astrophysical modeling.

The Laser Interferometer Space Antenna (LISA) is a planned space-based observatory to measure gravitational waves in the millihertz frequency band. This frequency band is expected to be dominated by signals from millions of Galactic binaries and tens of merging massive black hole binaries. The LISA Data Challenge 2a is focused on robust signal extraction from a blend of these two types of gravitational wave signals. Here, we introduce a novel high performance and cost-effective global fit pipeline extracting and characterizing galactic binary and massive black hole binary signals and estimate the noise of the residual. We perform the pipeline in a time-evolving weekly analysis starting with an observation time of one week until we reach a full year. As expected we detect more galactic binaries and massive black hole binaries bringing the noise estimate of the residual closer to the instrument noise with each week of additional observation time. Furthermore, we present a novel maximum likelihood estimate-based algorithm for extracting multiple massive black hole binaries.…

We investigate the impact of postadiabatic (1PA) terms on parameter estimation for extreme and intermediate mass-ratio inspirals using state-of-the-art waveform models. Our analysis is the first to employ Bayesian inference to assess systematic errors for 1PA waveforms. We find that neglecting 1PA terms introduces significant biases for the (small) mass ratio $\ensuremath{\epsilon}\ensuremath{\gtrsim}{10}^{\ensuremath{-}5}$ for quasi circular orbits in Schwarzschild spacetime, which can be mitigated with resummed 3PN expressions at 1PA order. Moreover, we show that the secondary spin is strongly correlated with the other intrinsic parameters, and it can not be constrained for $\ensuremath{\epsilon}\ensuremath{\lesssim}{10}^{\ensuremath{-}5}$. Finally, we highlight the need for addressing eccentric waveform systematics in the small-mass-ratio regime, as they yield stronger biases than the circular limit in both intrinsic and extrinsic parameters.

We study the effects of exceptionally light QCD axions on the stellar configuration of white dwarfs. At finite baryon density, the nonderivative coupling of the axion to nucleons displaces the axion from its in-vacuum minimum, which implies a reduction of the nucleon mass. This dramatically alters the composition of stellar remnants. In particular, the modifications of the mass-radius relationship of white dwarfs allow us to probe large regions of unexplored parameter space without requiring that axions are dark matter. Published by the American Physical Society 2024

In this work, we investigate spectral complexity and Krylov complexity in quantum billiard systems at finite temperature. We study both circle and stadium billiards as paradigmatic examples of integrable and nonintegrable quantum-mechanical systems, respectively. We show that the saturation value and timescale of spectral complexity may be used to probe the nonintegrability of the system since we find that when computed for the circle billiard, it saturates at a later timescale compared to the stadium billiards. This observation is verified for different temperatures. Furthermore, we study the Krylov complexity of the position operator and its associated Lanczos coefficients at finite temperature using the Wightman inner product. We find that the growth rate of the Lanczos coefficients saturates the conjectured universal bound at low temperatures. Additionally, we also find that even a subset of the Lanczos coefficients can potentially serve as an indicator of integrability, as they demonstrate erratic behavior specifically in the circle billiard case, in contrast to the stadium…

Recently, it has been proposed that the black hole greybody factors can be important to model ringdown spectral amplitudes. We study the stability of greybody factors against a small-bump correction in the perturbation equation. We find (I) that the greybody factor is stable in the frequency region relevant to ringdown and (II) that it is destabilized at higher frequencies, especially for a sharper bump correction. This behavior is similar to the case of higher overtones, which is also very sensitive to a small correction. We clarify this (in)stability with the WKB analysis. As the greybody factor is stable at the frequency region relevant to the main part of ringdown, we conclude that the greybody factor is suitable to model ringdown amplitude. In order to investigate a bump correction in a self-consistent manner, we consider the small-bump correction that can be realized in the general framework of effective field theory of black hole perturbations.

An analysis of solar neutrino data from the fourth phase of Super-Kamiokande (SK-IV) from October 2008 to May 2018 is performed and the results are presented. The observation time of the dataset of SK-IV corresponds to 2970 days and the total live time for all four phases is 5805 days. For more precise solar neutrino measurements, several improvements are applied in this analysis: lowering the data acquisition threshold in May 2015, further reduction of the spallation background using neutron clustering events, precise energy reconstruction considering the time variation of the PMT gain. The observed number of solar neutrino events in 3.49–19.49 MeV electron kinetic energy region during SK-IV is 65,443 − 388 + 390 ( stat . ) ± 925 ( syst . ) events. Corresponding B 8 solar neutrino flux is ( 2.314 ± 0.014 ( stat . ) ± 0.040 ( syst . ) ) × 10 6 cm − 2 s − 1 , assuming a pure electron-neutrino flavor component without neutrino oscillations. The flux combined with all SK phases up to SK-IV is ( 2.336 ± 0.011 ( stat . ) ± 0.043 ( syst . ) ) × 10 6 cm − 2 s − 1 . Based on the neutrino…

Recent measurements and analyses from the Dark Energy Spectroscopic Instrument (DESI) collaboration and supernova surveys combined with cosmic microwave background (CMB) observations, indicate that the dark energy density changes over time. Here we explore the possibility that the dark energy density is constant, but that the cosmological recombination history differs substantially from that in $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$. When we free up the ionization history, but otherwise assume the standard cosmological model, we find the combination of CMB and DESI data prefer (i) early recombination qualitatively similar to models with small-scale clumping, (ii) a value of ${H}_{0}$ consistent with the estimate from the SH0ES collaboration at the $2\ensuremath{\sigma}$ level, and (iii) a higher CMB lensing power, which takes pressure off of otherwise tight constraints on the sum of neutrino masses. Our work provides additional motivation for finding physical models that lead to the small-scale clumping that can theoretically explain the ionization history preferred by DESI and…

Perturbative, or effective field theory (EFT)-based, full-shape analyses of galaxy clustering data involve ``nuisance parameters'' to capture various observational effects such as the galaxy-dark matter connection (galaxy bias). We present an efficient approach to set informative physically motivated priors on these parameters. We extract these priors from simulated galaxy catalogs based on halo occupation distribution (HOD) models. First, we build a joint distribution between EFT galaxy bias and HOD parameters from a set of 10,500 HOD mock catalogs. We use the field level EFT technique that allows for cosmic variance cancellation, enabling a precision calibration of EFT parameters from computationally inexpensive small-volume simulations. Second, we use neural density estimators---normalizing flows---to model the marginal probability density of the EFT parameters, which can be used as a prior distribution in full shape analyses. As a first application, we use our HOD-based priors in a new analysis of galaxy power spectra and bispectra from the BOSS survey in the context of single…

We investigate the probable existence of dark matter in the interior of neutron stars. Despite the current state of knowledge, the observational properties of neutron stars have not definitively ruled out the possibility of dark matter. Our research endeavors to shed light on this intriguing mystery by examining how certain neutron star properties, including mass, radius, and tidal deformability, might serve as constraints for the dark matter model. In our investigation, we adopt a two-fluid approach to calculate the properties of neutron stars. For the nuclear matter equation-of-state (EOS), we employ several realistic EOS derived from the relativistic mean field model (RMF), each exhibiting varying stiffness and composition. In parallel, we look into the dark matter EOS, considering fermionic matter with repulsive interaction described by a relativistic mean field Lagrangian. A reasonable range of parameters is sampled meticulously. Our study primarily focuses on exploring correlations between the dark matter model parameters and different neutron star properties using a rich set…

We present a comprehensive study of compact stars admixed with nonself-annihilating self-interacting fermionic dark matter, delineating the dependence on the nuclear equation of state by considering the two limiting parametrized equations of state for neutron star matter obtained by smoothly matching the low-density chiral effective theory and the high-density perturbative QCD. These two parametrizations are the limiting cases of a wide variety of smooth equations of state, i.e., the softest and stiffest possible one without a phase transition, that generate masses and radii compatible with $2{M}_{\ensuremath{\bigodot}}$ observations and the tidal constraint from GW170817. With an exhaustive analysis of the possible stable mass-radius configurations, we determine the quantity of dark matter contained in stars with masses and radii compatible with the aforementioned astrophysical constraints. We find that for dark particle masses of a few tenths of GeV, the dark core collapses and no stable solutions are found for the two limiting ordinary matter equations of state. For lower masses,…

It has been shown, via specific examples and a pseudospectrum analysis, that the black hole quasinormal spectra are unstable. The implication of such a result for gravitational-wave physics and of our understanding of black holes is, still, unclear. The purpose of this work is twofold: (i) we show that some of the setups leading to instabilities are unphysical and triggered by exotic matter or extreme spacetimes; (ii) nevertheless, we also show simple examples of compelling physical scenarios leading to spectral instabilities. Our results highlight the importance of understanding the overtone content of time-domain waveforms, and their detectability.

The paper successfully models X-ray observational aspects of Quasi-Periodic Eruptions (QPEs) in galactic nuclei as due to collisions between a Tidal Disruption Event (TDE) accretion disk and a stellar mass black hole or main sequence star orbiting around a nuclear supermassive black hole (SMBH). This can have key implications in understanding EMRIs and stellar orbits in the vicinity of SMBHs.

Based on lattice QCD results of equation of state and baryon number susceptibility at zero baryon chemical potential, and supplemented by machine learning techniques, we construct the analytic form of the holographic black hole metric in the Einstein-Maxwell-Dilaton framework for pure gluon, 2-flavor, and ( 2+1 )-flavor systems, respectively. The dilaton potentials solved from Einstein equations are in good agreement with the extended nonconformal DeWolfe-Gubser-Rosen type dilaton potentials fixed by lattice QCD equation of state, which indicates the robustness of the Einstein-Maxwell-Dilaton framework. The predicted critical end point in the ( 2+1 )-flavor system is located at ( Tc=0.094 GeV , μBc=0.74 GeV ), which is close to the results from the realistic Polyakov-Nambu-Jona-Lasinio model, the functional renormalization group, and the holographic model with extended DeWolfe-Gubser-Rosen dilaton potential. Published by the American Physical Society 2024

Bayesian model averaging is a practical method for dealing with uncertainty due to model specification. Use of this technique requires the estimation of model probability weights. In this work, we revisit the derivation of estimators for these model weights. Use of the Kullback-Leibler divergence as a starting point leads naturally to a number of alternative information criteria suitable for Bayesian model weight estimation. We explore three such criteria, known to the statistics literature before, in detail: a Bayesian analog of the Akaike information criterion which we call the BAIC, the Bayesian predictive information criterion, and the posterior predictive information criterion (PPIC). We compare the use of these information criteria in numerical analysis problems common in lattice field theory calculations. We find that the PPIC has the most appealing theoretical properties and can give the best performance in terms of model-averaging uncertainty, particularly in the presence of noisy data, while the BAIC is a simple and reliable alternative.

We present a comprehensive reassessment of the state of interacting dark energy (DE) cosmology, namely models featuring a nongravitational interaction between dark matter and DE. To achieve high generality, we extend the dark sector physics by considering two different scenarios: a nondynamical DE equation of state w 0 ≠ − 1 , and a dynamical w ( a ) = w 0 + w a ( 1 − a ) . In both cases, we distinguish two different physical regimes resulting from a phantom or quintessence equation of state. To circumvent early time superhorizon instabilities, the energy-momentum transfer should occur in opposing directions within the two regimes, resulting in distinct phenomenological outcomes. We study quintessence and phantom nondynamical and dynamical models in light of two independent cosmic microwave background (CMB) experiments—the Planck satellite and the Atacama Cosmology Telescope. We analyze CMB data both independently and in combination with supernovae distance moduli measurements from the catalog and baryon acoustic oscillations from the SDSS-IV eBOSS survey. Our results update and…

Complete waveform models able to account for arbitrary nonplanar orbits represent a holy grail in current gravitational-wave astronomy. Here, we take a step toward this direction and present a simple yet efficient prescription to obtain the evolution of the spin vectors and of the orbital angular momentum along noncircularized orbits, that can be applied to any eccentric aligned-spins waveform model. The scheme employed is motivated by insights gained from the post-Newtonian (PN) regime. We investigate the phenomenology of the Euler angles characterizing the time-dependent rotation that connects the coprecessing frame to the inertial one, gauging the importance of noncircular terms in the evolution of the spins of a precessing binary. We demonstrate that such terms are largely negligible, irrespectively of the details of the orbit. Such insights are confirmed by studying the radiation-frame of a few eccentric, precessing numerical relativity (NR) simulations. Our investigations confirm that the usual ``twisting'' technique employed for quasispherical systems can be safely applied to…

We investigate quadratic quasinormal mode coupling in black hole spacetime through numerical experiments of single perturbed black holes using both numerical relativity and second-order black hole perturbation theory. Focusing on the dominant $\ensuremath{\ell}=|m|=2$ quadrupolar modes, we find good agreement (within $\ensuremath{\sim}10%$) between these approaches, with discrepancies attributed to truncation error and uncertainties from mode fitting. Our results align with earlier studies extracting the coupling coefficients from select binary black hole merger simulations, showing consistency for the same remnant spins. Notably, the coupling coefficient is insensitive to a diverse range of initial data, including configurations that led to a significant (up to 5%) increase in the remnant black hole mass. These findings present opportunities for testing the nonlinear dynamics of general relativity with ground-based gravitational wave observatories. Lastly, we provide evidence of a bifurcation in coupling coefficients between counterrotating and corotating quasinormal modes as black…

Very recently, the major pulsar timing array collaborations, including CPTA, EPTA, InPTA, NANOGrav, and PPTA, reported their results from searches for an isotropic stochastic gravitational wave background (SGWB), collectively representing positive evidence for a SGWB. In this work, we assessed the credibility of interpreting the Hellings-Downs correlated free-spectrum process of EPTA, PPTA, and NANOGrav as either the result of supermassive black hole binary mergers or various stochastic SGWB sources that originated in the early Universe, including first-order phase transitions, cosmic strings, domain walls, and large-amplitude curvature perturbations. Our results show that the current new datasets do not distinctly favor one specific SGWB source over the others based on Bayesian analysis. We also place constraints on new physics for the SGWB sources.

GstLAL is a stream-based matched-filtering search pipeline aiming at the prompt discovery of gravitational waves from compact binary coalescences such as the mergers of black holes and neutron stars. Over the past three observation runs by the LIGO, Virgo, and KAGRA Collaboration, the GstLAL search pipeline has participated in several tens of gravitational wave discoveries. The fourth observing run (O4) is set to begin in May 2023 and is expected to see the discovery of many new and interesting gravitational wave signals which will inform our understanding of astrophysics and cosmology. We describe the current configuration of the GstLAL low-latency search and show its readiness for the upcoming observation run by presenting its performance on a mock data challenge. The mock data challenge includes 40 days of LIGO Hanford, LIGO Livingston, and Virgo strain data along with an injection campaign in order to fully characterize the performance of the search. We find an improved performance in terms of detection rate and significance estimation as compared to that observed in the O3…

We present the angular diameter distance measurement obtained with the baryonic acoustic oscillation (BAO) feature from galaxy clustering in the completed Dark Energy Survey, consisting of six years (Y6) of observations. We use the Y6 BAO galaxy sample, optimized for BAO science in the redshift range $0.6 0.75$ from any survey and the most precise measurement at any redshift from photometric surveys. The analysis was performed blinded to the BAO position, and it is shown to be robust against analysis choices, data removal, redshift calibrations, and observational systematics.

I review and discuss the possible implications for inflation resulting from considering new physics in light of the Hubble tension. My study is motivated by a simple argument that the constraints on inflationary parameters, most typically the spectral index n s , depend to some extent on the cosmological framework. To avoid broadening the uncertainties resulting from marginalizing over additional parameters (typical in many alternative models), I first adopt the same alternative viewpoint of previous studies and analyze what happens if a physical theory can extra parameters to nonstandard values. Focusing on the dark energy equation of state w and the effective number of relativistic species N eff , I confirm that physical theories able to fix w ≈ − 1.2 or N eff ≈ 3.9 produce values of H 0 from Cosmic Microwave Background and Baryon Acoustic Oscillations in line with the local distance ladder estimate. While in the former case I do not find any relevant implications for inflation, in the latter scenarios, I observe a shift toward n s ≈ 1 . From a model-selection perspective, both…

We explore the consequences of imposing robust thermodynamic constraints arising from perturbative quantum chromodynamics (QCD) when inferring the dense-matter equation-of-state (EOS). We find that the termination density, up to which the EOS modeling is performed in an inference setup, strongly affects the constraining power of the QCD input. This sensitivity in the constraining power arises from EOSs that have a specific form, with drastic softening immediately above the termination density followed by a strong stiffening. We also perform explicit modeling of the EOS down from perturbative-QCD densities to construct a new QCD likelihood function that incorporates additional perturbative-QCD calculations of the sound speed and is insensitive to the termination density, which we make publicly available.

The detection of gravitational waves resulting from the coalescence of binary black holes by the LIGO-Virgo-Kagra Collaboration has inaugurated a new era in gravitational physics. These gravitational waves provide a unique opportunity to test Einstein’s general relativity and its modifications in the regime of extreme gravity. A significant aspect of such tests involves the study of the ringdown phase of gravitational waves from binary black hole coalescence, which can be decomposed into a superposition of various quasinormal modes. In general relativity, the spectra of quasinormal modes depend on the mass, spin, and charge of the final black hole, but they can also be influenced by additional properties of the black hole spacetime, as well as corrections to the general theory of relativity. In this work, we focus on a specific modified theory known as dynamical Chern-Simons gravity. We employ the modified Teukolsky formalism developed in a previous study and lay down the foundations to investigate perturbations of slowly rotating black holes admitted by the theory. Specifically, we…

The predictivity of many nonthermal dark matter (DM) models is marred by the gravitational production background. Nevertheless, if the reheating temperature T R is low, the gravitationally produced relics can be diluted. We study the freeze-in dark matter production mechanism at temperatures below the dark matter mass. In this case, the coupling to the thermal bath has to be significant to account for the observed dark matter relic density. As a result, the direct DM detection experiments already probe such freeze-in models, excluding significant parts of parameter space. Published by the American Physical Society 2024

Due to rapidly improving quantum computing hardware, Hamiltonian simulations of relativistic lattice field theories have seen a resurgence of attention. This computational tool requires turning the formally infinite-dimensional Hilbert space of the full theory into a finite-dimensional one. For gauge theories, a widely used basis for the Hilbert space relies on the representations induced by the underlying gauge group, with a truncation that keeps only a set of the lowest dimensional representations. This works well at large bare gauge coupling, but becomes less efficient at small coupling, which is required for the continuum limit of the lattice theory. In this work, we develop a new basis suitable for the simulation of an SU(2) lattice gauge theory in the maximal tree gauge. In particular, we show how to perform a Hamiltonian truncation so that the eigenvalues of both the magnetic and electric gauge-fixed Hamiltonian are mostly preserved, which allows for this basis to be used at all values of the coupling. Little prior knowledge is assumed, so this may also be used as an…

The thermal plasma in the early Universe produced a stochastic gravitational wave (GW) background, which peaks today in the microwave regime and was dubbed the cosmic gravitational microwave background (CGMB). In previous works, only single graviton production processes that contribute to the CGMB have been considered. Here, we also investigate graviton pair production processes and show that these can lead to a significant contribution if the ratio between the maximum temperature and the Planck mass, Tmax/mp , divided by the internal coupling in the heat bath is large enough. As the dark matter freeze-in production mechanism is conceptually very similar to the GW production mechanism from the primordial thermal plasma, we refer to the latter as “GW freeze-in production.” We show that quantum gravity effects appear in single graviton production and are smaller by a factor (Tmax/mp)2 than the leading order contribution. In our work, we explicitly compute the CGMB spectrum within a scalar model with quartic interaction. Published by the American Physical Society 2024

Within the framework of relative and absolute quantum field theories (QFTs), we present a general formalism for understanding polarizations of the intermediate defect group and constructing noninvertible duality defects in theories in 2k spacetime dimensions with self-dual gauge fields. We introduce the polarization pair, which fully specifies absolute QFTs as far as their ( k−1 )-form defect groups are concerned, including their ( k−1 )-form symmetries, global structures (including discrete θ -angle), and local counterterms. Using the associated symmetry topological field theory (TFT), we show that the polarization pair is capable of succinctly describing topological manipulations, e.g., gauging ( k−1 )-form global symmetries and stacking counterterms, of absolute QFTs. Furthermore, automorphisms of the ( k−1 )-form charge lattice naturally act on polarization pairs via their action on the defect group; they can be viewed as dualities between absolute QFTs descending from the same relative QFT. Using this formalism, we present a prescription for building noninvertible symmetries of…

Rotating black holes can produce superradiant clouds of ultralight bosons. When the black hole is part of a binary system, its cloud can undergo resonances and ionization. These processes leave a distinct signature on the gravitational waveform that depends on the cloud's properties. To determine the state of the cloud by the time the system enters the band of future millihertz detectors, we study the chronological sequence of resonances encountered during the inspiral. For the first time, we consistently take into account the nonlinearities induced by the orbital backreaction and we allow the orbit to have generic eccentricity and inclination. We find that the resonance phenomenology exhibits striking new features. Resonances can "start" or "break" above critical thresholds of the parameters, which we compute analytically, and induce dramatic changes in eccentricity and inclination. Applying these results to realistic systems, we find two possible outcomes. If the binary and the cloud are sufficiently close to counter-rotating, the cloud survives in its original state until the…

We compute the gravitational wave (GW) spectrum sourced by the sound waves produced during a first-order phase transition in the radiation-dominated epoch. The correlator of the velocity field perturbations is evaluated in accordance with the sound shell model. In our derivation we include the effects of the expansion of the Universe, which are relevant in particular for sourcing processes whose time duration is comparable with the Hubble time. Our results show a causal growth of the GW spectrum at small frequencies, ${\mathrm{\ensuremath{\Omega}}}_{\mathrm{GW}}\ensuremath{\sim}{k}^{3}$, possibly followed by a linear regime ${\mathrm{\ensuremath{\Omega}}}_{\mathrm{GW}}\ensuremath{\sim}k$ at intermediate $k$, depending on the phase transition parameters. Around the peak, we find a steep growth that approaches the $\ensuremath{\sim}{k}^{9}$ scaling previously found within the sound shell model. The resulting bump around the peak of the GW spectrum may represent a distinctive feature of GWs produced from acoustic motion. Nothing similar has been observed for vortical…

R7-branes are a class of recently discovered nonsupersymmetric real codimension-two duality defects in type IIB string theory predicted by the swampland cobordism conjecture. For type IIB realizations of 6D SCFTs with N=(2,0) supersymmetry, wrapping an R7-brane “at infinity” leads to a topological operator associated with a zero-form charge conjugation symmetry that squares to the identity. Similar considerations hold for those theories obtained from further toroidal compactification, but this can be obstructed by bundle curvature effects. Using some minimal data on the topological sector of the R7-branes, we extract the associated fusion rules for these charge conjugation operators. More broadly, we sketch a top down realization of various topological operators/interfaces associated with C , R , and T transformations. We also use holography to provide strong evidence for the existence of the R7-brane which is complementary to the cobordism conjecture. Similar considerations apply to other string-realized QFTs with symmetry operators constructed via nonsupersymmetric branes which…

In this paper, we investigate the quasinormal mode (QNM) spectra for the scalar perturbation over the quantum-corrected black hole (BH) known as the quantum Oppenheimer-Snyder (qOS) BH. The fundamental modes of the qOS BH exhibit two key properties. First, there is a nonmonotonic behavior concerning the quantum-corrected parameter for zero multipole number. Second, the quantum gravity effects result in slower decay modes. For higher overtones, a significant deviation becomes evident between the quasinormal frequencies (QNFs) of the qOS and Schwarzschild BHs. The intervention of quantum gravity corrections induces a significant outburst of overtones. This outburst of these overtones can be attributed to the distinctions near the event horizons between the Schwarzschild and qOS BHs. Therefore, overtones can serve as a means to probe physical phenomena or disparities in the vicinity of the event horizon.