We explore the properties of a simple renormalizable shift-symmetric model with a higher-derivative kinetic energy and quartic-derivative coupling that can serve as a toy model for higher-derivative theories of gravity. The scattering amplitude behaves as in a normal effective field theory below the threshold for the production of ghosts, but has an unexpectedly soft behavior above the threshold. The physical running of the parameters is extracted from the two-point and four-point amplitudes. The results are compared to those obtained by other methods and are found to agree only in limiting cases. We draw several lessons that may also apply to gravity.

We show that even $\zeta$-functions may be removed from the $\beta$-functions of general multicoupling theories up to high loop order by means of coupling redefinitions. For theories whose $\beta$-function is determined by the anomalous dimensions of the fields, such as supersymmetric theories, this corresponds to a renormalization scheme change to a momentum subtraction scheme.

We present a public catalog of numerical-relativity binary-black-hole simulations. The catalog contains datasets from 80 distinct configurations of precessing binary-black-hole systems, with mass ratios up to $m_2/m_1=8$, dimensionless spin magnitudes on the larger black hole up to $|{\overrightarrow{S}}_2|/m_2^2=0.8$ (the small black hole is nonspinning), and a range of five values of spin misalignment for each mass-ratio/spin combination. We discuss the physical properties of the configurations in our catalog, and assess the accuracy of the initial configuration of each simulation and of the gravitational waveforms. We perform a careful analysis of the errors due to the finite resolution of our simulations and the finite distance from the source at which we extract the waveform data and provide a conservative estimate of the mismatch accuracy. We find that the upper limit on the mismatch uncertainty of our waveforms (including multipoles $\ell \le 5$) is 0.4%. In doing this we present a consistent approach to combining mismatch uncertainties from multiple error sources. We compare this release to previous catalogs and discuss how these new simulations complement the existing public datasets. In particular, this is the first catalog to uniformly cover this parameter space of single-spin binaries and there was previously only sparse coverage of the precessing-binary parameter space for mass ratios $\gtrsim 5$. We discuss applications of these new data, and the most urgent directions for future simulation work.

In this work, we explore the effects of surrounding dark matter featuring different equations of state on the axial gravitational quasinormal modes of supermassive black holes situated at the center of galaxies. Our attention primarily rests on dark matter exhibiting a spike structure, originating from relativistic Bondi accretion through an adiabatic process, which diminishes at a certain distance from the black hole. We analyze how varying the equation of state of the dark matter influences the properties of the spacetime in the black hole’s vicinity. Our findings reveal that different states of dark matter spikes correspondingly affect the black hole’s quasinormal modes. In particular, we identify deviations in both the ringing frequency and damping time, reaching magnitudes of up to ${10}^{-3}$ for certain parameter values. These variations can potentially be detected by upcoming space-borne detectors. Our findings thus indicate the feasibility of discerning and limiting the essential properties of dark matter surrounding supermassive black holes using future gravitational wave detections, particularly in the case of extreme mass ratio inspiral systems.

We propose a new method to determine the physical parameters of Kerr black holes (namely, specific angular momentum $a$, inclination angle $i$, and distance $D$ from an observer) only from the shadow’s information such as the size and shape. Key points in our method are (i) to treat the distance as a free parameter, (ii) to expand the shadow’s outline as a Fourier series, and (iii) to construct principal components from the Fourier coefficients. These points enable us to obtain a one-to-one mapping between three principal components, being observables characterizing the size and deviation of shadow’s shape from a circular disk, and the values of three parameters ($D/M,a/M$, $i$), where $M$ is the mass of black hole. Our method is applicable to various type of black holes and even to ones with accretion disks.

We study gravitational lensing of gravitational waves taking into account the spin of gravitational waves coupled with a dragged spacetime made by a rotating object. We decompose the phase of gravitational waves into helicity-dependent and helicity-independent components with spin optics, analyzing waves whose wavelengths are shorter than the curvature radius of a lens object. We analytically confirm that the trajectory of gravitational waves splits depending on the helicity, generating additional time delay and elliptical polarization onto the helicity-independent part. We exemplify monochromatic gravitational waves lensed by a Kerr black hole and derive the analytical expressions of corrections in phase and magnification. The corrections are enhanced for longer wavelengths, potentially providing a novel probe of rotational properties of lens objects in low-frequency gravitational-wave observations in the future.

The next-generation CMB experiments are expected to constrain the tensor-to-scalar ratio $r$ with high precision. Delensing is an important process as the observed CMB $B$-mode polarization that contains the primordial tensor perturbation signal is dominated by a much larger contribution due to gravitational lensing. To do so successfully, it is useful to explore methods for lensing reconstruction beyond the traditional quadratic estimator (QE) (which will become suboptimal for the next-generation experiments), and the maximum a posterior estimator (which is still currently under development). In Caldeira et al. [Astron. Comput. 28, 100307 (2019)], the authors showed that a neural network (NN) method using the ResUNet architectrue performs better than the QE and slightly suboptimally compared to the iterative estimator in terms of the lensing reconstruction performance. In this work, we take one step further to evaluate the delensing performance of these estimators on maps with primordial tensor perturbations using a standard delensing pipeline, and show that the delensing performance of the NN estimator is optimal, agreeing with that of a converged iterative estimator, when tested on a suite of simulations with $r=0.01$ and $r=0.001$ for $12.7°\times 12.7°$ maps at a CMB-Stage 4 like polarization noise level $1\mathrm{\mu }\mathrm{K}\mathrm{arcmin}$ and 1’ beam. We found that for the purpose of delensing, it is necessary to train and evaluate the NN on a set of CMB maps with $l<l_{\mathrm{cut}}$ removed, in order to avoid spurious correlations on the scales of interest for the final delensed $B$-mode power spectrum $l<l_{\mathrm{cut}}$, similar to what was known previously for the QE and the iterative estimator. We also present various NN training techniques that can be extended for a simultaneous treatment of foregrounds and more complex instrumental effects where the modeling is more uncertain.

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 of EOSs. Interestingly, our results reveal a promising correlation between the dark matter model parameters and stellar properties, particularly when we ignore the uncertainties in the nuclear matter EOS. However, when introducing uncertainties in the nuclear sector, the correlation weakens, suggesting that the task of conclusively constraining any particular dark matter model might be challenging using global properties alone, such as mass, radius, and tidal deformability. Notably, we find that dark-matter admixed stars tend to have higher central baryonic density, potentially allowing for non-nucleonic degrees of freedom or direct Urca processes in stars with lower masses. There is also a tantalizing hint regarding the detection of stars with the same mass but different surface temperatures, which may indicate the presence of dark matter. With our robust and extensive dataset, we delve deeper and demonstrate that even in the presence of dark matter, the semiuniversal C-Love relation remains intact. This captivating finding adds another layer of complexity to the interplay between dark matter and neutron star properties.

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, we introduce main features of the pulse profile corresponding to the DM admixed NS as a novel observable quantity. We find that the depth of minimum fluxes in the pulse profiles crucially depends on the amount of DM around NS and its compactness. The current/future astrophysics missions may test for the possibility of the existence of DM within NSs and break the degeneracies between different scenarios via multiple observations.

We investigate the hypothetical X17 boson on neutron stars and quark stars (QSs) using various hadronic equation of states (EoSs) with phenomenological or microscopic origin. Our aim is to set realistic constraints on its coupling constant and the mass scaling, with respect to causality and various possible upper mass limits and the dimensionless tidal deformability ${\mathrm{\Lambda }}_{1.4}$. In particular, we pay special attention to two main phenomenological parameters of the X17, one is related to the coupling constant $\mathrm{g}$ that it has with hadrons or quarks and the other with the in-medium effects through regulator $\mathrm{C}$. Both are very crucial concerning the contribution on the total energy density and pressure. In the case of considering the X17 as a carrier of nuclear force in relativistic mean field theory, an admixture into the vector boson segment was constrained by 20% and 30%. In our investigation, we came to the general conclusion that the effect of the hypothetical X17 both on neutron and QSs is constrained mainly by the causality limit, which is a specific property of each EoS, and it depends on the interplay between the two main parameters, the interaction coupling $\mathrm{g}$ and the in-medium effects regulator $\mathrm{C}$. These effects are more pronounced in the case of QSs concerning all the bulk properties.

Time-domain (TD) Bayesian inference is important in ringdown analysis for gravitational wave (GW) astronomy. The validity of this method has been well studied by Isi and Farr [arXiv:2202.02941]. Using GW190521 as an example, we study the TD method in detail by comparing it with the frequency-domain (FD) method as a complement to previous study. We argue that the autocovariance function (ACF) should be calculated from the inverse fast Fourier transform of the power spectral density (PSD), which is usually estimated by the Welch method. In addition, the total duration of the GW data that are used to estimate the PSD and the slice duration of the truncated ACF should be long enough. Only when these conditions are fully satisfied can the TD method be considered sufficiently equivalent to the FD method.

$R^2$-Higgs inflation stands out as one of the best-fit models of Planck data. Using a covariant formalism for the inflationary dynamics and the production of helical gauge fields, we show that the observed baryon asymmetry of the Universe (BAU) can be obtained when this model is supplemented by a dimension-six $CP$-violating term $\sim (R/{\mathrm{\Lambda }}^2)B_{\mu \nu }{\tilde{B}}^{\mu \nu }$ in the hypercharge sector. At linear order, values of $\mathrm{\Lambda }\simeq 2.5\times {10}^{-5}{M}_{\mathrm{P}}$ produce, in the $R^2$-like regime, sufficient helical hypermagnetic fields to create the observed matter-antimatter asymmetry during the electroweak crossover. However, the Schwinger effect of fermion pair production can play a critical role in this context, and that scale is significantly lowered when the backreaction of the fermion fields on the gauge field production is included. In all cases, the helical field configurations can remain robust against washout after the end of inflation.

We study the spontaneous emission of a photon during the transitions between relativistic Landau states of an electron in a constant magnetic field that can reach the Schwinger value of $H_c=4.4\times {10}^9\mathrm{T}$. In contrast to the conventional method, in which detection of both the final electron and the photon are implied in a certain basis, here we derive the photon state as it evolves from the process itself. It is shown that the emitted photon state represents a twisted Bessel beam propagating along the field axis with a total angular momentum (TAM) projection onto this axis $\ell -{\ell }^{\prime }$, where $\ell$ and ${\ell }^{\prime }$ are the TAM of the initial electron and of the final one, respectively. Thus, the majority of the emitted photons turn out to be twisted, with $\ell -{\ell }^{\prime }\gtrsim 1$, even when the magnetic field reaches the critical value of $H\sim H_c$. The transitions without a change of the electron angular momentum, ${\ell }^{\prime }=\ell$, are possible, yet much less probable. We also compare our findings with those for a spinless charged particle and demonstrate their good agreement for the transitions without change of the electron spin projection even in the critical fields, while the spin-flip transitions are generally suppressed. In addition, we argue that whereas the ambiguous choice of an electron spin operator affects the differential probability of emission, this problem can partially be circumvented for the photon evolved state because it is the electron TAM rather than the spin alone that defines the TAM of the emitted twisted photon.

We present a comprehensive analysis of the vacuum stability of the two-Higgs-doublet model, for both type-I and type-II, augmented by vectorlike quarks in singlet, doublet, or triplet representations. We review the model briefly before introducing the extra fermionic states and their interactions, and impose restrictions on the parameters coming from both theoretical considerations and experimental bounds. We then study the renormalization group equation evolution of the parameters of the model in order to isolate the parameter regions that satisfy vacuum stability requirements. We then add the electroweak precision observables to ensure that the resulting parameter space is consistent with the data. We include complete expressions for the renormalization group equations and the $\mathbb{S}$ and $\mathbb{T}$ parameters used. Finally, we summarize the effects of various vectorlike quark representations on the parameter space. We indicate the regions constrained, highlighting the differences between representations in type-I and type-II, and pinpoint the effects of the interplay between the extended model and the additional fermions.

We examine a variety of renormalization schemes in QCD based on its 3-point vertices where the $\beta$-functions, gluon, ghost, quark and quark mass anomalous dimensions in each scheme do not depend on ${\zeta }_4$ or ${\zeta }_6$ in an arbitrary linear covariant gauge at five loops. We comment on the $C$-scheme.

We explore the quantum electrodynamic (QED) corrections to the ${\mathrm{\Xi }}_c^{+}-{\mathrm{\Xi }}_c^{\prime +}$ mixing within the framework of light-front quark model (LFQM) in the three-quark picture. After explicitly investigating the relation between the ${\mathrm{\Xi }}_c-{\mathrm{\Xi }}_c^{\prime }$ mixing and the flavor SU(3) and heavy quark symmetry breaking, we derive the QED contributions to the ${\mathrm{\Xi }}_c^{+}-{\mathrm{\Xi }}_c^{\prime +}$ mixing angle. Numerical results indicate the QED contribution is smaller than the one from the mass difference between the strange and up/down quark provided by a recent lattice quantum chromodynamics analysis. Adding these contributions together we find that at this stage the ${\mathrm{\Xi }}_c^{+}-{\mathrm{\Xi }}_c^{\prime +}$ mixing is small and still incapable to account for the large SU(3) symmetry breaking in the semileptonic ${\mathrm{\Xi }}_c$ decays.

We compute and explore numerically the finite system size correction to next-to-leading-order $2\to 2$ scattering in massive scalar ${\varphi }^4$ theory. The derivation uses “denominator regularization” (instead of the usual dimensional regularization) on a spacetime with spatial directions compactified to a torus, with characteristic lengths not necessarily of equal size. We determine a useful analytic continuation of the generalized Epstein zeta function to isolate the usual UV divergence. Self-consistently, the renormalized finite system size correction reduces to zero as the system size goes to infinity and, further, satisfies the optical theorem. One of our checks of unitarity leads to a generalization of a number-theoretic result from Hardy and Ramanujan. Precise numerical exploration of the finite system size correction to the amplitude and coupling when two spatial dimensions are finite requires the exploitation of the analytic structure of the finite system size result via a dispersion relation. We find that the finite system size scattering amplitude exhibits “geometric” bound states. Even away from these bound states, the finite system size correction to the effective coupling can be large.

An updated global fit on the parameter-space of the aligned two-Higgs-doublet model is performed with the help of the open-source package hepfit, assuming the Standard-Model Higgs to be the lightest scalar. No new sources of $CP$ violation, other than the phase in the Cabibbo-Kobayashi-Maskawa matrix of the Standard Model, are considered. A similar global fit was previously performed by O. Eberhardt et al. [Global fits in the aligned two-Higgs-doublet model, J. High Energy Phys. 05 (2021) 005] with a slightly different set of parameters. Our updated fit incorporates improved analyses of the theoretical constraints required for the perturbative unitarity and boundedness of the scalar potential from below, additional flavor observables and updated data on direct searches for heavy scalars at the LHC, Higgs signal strengths, and electroweak precision observables. Although not included in the main fit, the implications of the CDF measurement of the $W^{\pm }$ mass are also discussed.

Supersymmetric models with the anomaly-mediated supersymmetry (SUSY) breaking (AMSB) form for soft SUSY breaking terms arise in two different settings: (1) extra-dimensional models where SUSY breaking occurs in a sequestered sector, and (2) $4-d$ models with dynamical SUSY breaking in a hidden sector where scalars gain masses of order the gravitino mass $m_{3/2}$, but gaugino masses and trilinear soft terms are assumed to be of the AMSB form. Both models run into serious conflicts with (1) LHC sparticle and Higgs mass constraints, (2) constraints from winolike weakly interacting massive particle dark matter searches, and (3) bounds from naturalness. These conflicts may be avoided by introducing minor changes to the underlying phenomenological models consisting of nonuniversal bulk scalar Higgs masses and $A$ terms, providing a setting for natural anomaly mediation (nAMSB). In nAMSB, the wino is still expected to be the lightest of the gauginos, but the Higgsinos are expected to be the lightest electroweakinos (EWinos) in accord with naturalness. We examine what sorts of spectra are expected to emerge when nAMSB arises from a string landscape setting: While model 2 can only be natural for a Higgs mass $m_h\lesssim 123\mathrm{GeV}$, model 1 can accommodate naturalness along with $m_h\sim 125\mathrm{GeV}$ while still respecting LHC bounds on sparticle masses. We explore the LHC phenomenology of nAMSB models where we find that for Higgsino pair production, typically larger dilepton mass gaps arise from the soft dilepton-plus-jets signature than in models with gaugino mass unification. For wino-pair production, the higher $m_{3/2}$ portion of nAMSB parameter space is excluded by recent LHC bounds from gaugino pair production searches. We characterize the dominant LHC signatures arising from the remaining lower $m_{3/2}\sim 90–200\mathrm{TeV}$ range of parameter space, which should be fully testable at high-luminosity LHC via EWino pair production searches.

In this paper, we show the application of the quantum Metropolis sampling (QMS) algorithm to a toy gauge theory with discrete non-Abelian gauge group $D_4$ in ($2+1$)-dimensions, discussing in general how some components of hybrid quantum-classical algorithms should be adapted in the case of gauge theories. In particular, we discuss the construction of random unitary operators which preserve gauge invariance and act transitively on the physical Hilbert space, constituting an ergodic set of quantum Metropolis moves between gauge invariant eigenspaces, and introduce a protocol for gauge invariant measurements. Furthermore, we show how a finite resolution in the energy measurements distorts the energy and plaquette distribution measured via QMS, and propose a heuristic model that takes into account part of the deviations between numerical results and exact analytical results, whose discrepancy tends to vanish by increasing the number of qubits used for the energy measurements.