We solve the Einstein-Maxwell-Klein-Gordon system of equations and derive a compact, static axially symmetric magnetized object which is electrically neutral and made of two complex massive-charged scalar fields. We describe several properties of such solution, including the torus form of the matter density and the expected dipolar distribution of the magnetic field, with some peculiar features in the central regions. The solution shows no divergencies in any of the field and metric functions. A discussion is presented on a case where the gravitational and magnetic fields in the external region are similar to those of neutron stars.

We provide an explicit, closed, and compact expression for the Debye superpotential of a circular source. This superpotential is obtained by integrating the Green’s function of the Teukolsky Master Equation (TME). The Debye potential itself is then, for a particular configuration, calculated in the same manner as the ${\phi }_0$ field component is calculated from the Green’s function of the TME—by convolution of the Green’s function with sources. This way, we provide an exact field of charged ring and circular current on the Kerr background, finalizing thus the work of Linet.

Gravitational-wave parameter estimation for compact binary signals typically relies on sequential estimation of the properties of the detector Gaussian noise and of the binary parameters. This procedure assumes that the noise variance, expressed through its power spectral density, is perfectly known in advance. We assess the impact of this approximation on the estimated parameters by means of an analysis that simultaneously estimates the noise and compact binary parameters, thus allowing us to marginalize over uncertainty in the noise properties. We compare the traditional sequential estimation method and the new full marginalization method using events from the GWTC-3 catalog. We find that the recovered signals and inferred parameters agree to within their statistical measurement uncertainty. At current detector sensitivities, uncertainty about the noise power spectral density is a subdominant effect compared to other sources of uncertainty.

Tolman VII (TVII) is an analytical model for the nonrotating perfect fluid sphere with a simple quadratic density profile where its value is zero at the surface and a finite critical density value at the center. Therefore, compared to another analytical model like the constant density star, TVII is more realistic. Except for the dominant energy condition (DEC), which is violated in the region near the star’s center, the TVII satisfies all energy conditions. However, the causal condition is also violated for $\mathcal{C}>0.26$, and the maximum compactness of the TVII is restricted, i.e., ${\mathcal{C}}_{\max }\approx 0.38$. Here, we investigate the impacts of nonlocal gravity on the properties of the star of TVII within the range of the compactness of an ultracompact star ($0.33\le \mathcal{C}\le 0.44$). This nonlocal gravity version of TVII (NGTVII) is parametrized by the nonlocal parameters ($\tilde{\beta }$) and the compactness ($\mathcal{C}$). We have found that NGTVII can reach ${\mathcal{C}}_{\max }=0.43$ with ${\tilde{\beta }}_{\max }=3$ which is significantly more compact than TVII. The nonlocal density and pressure profile differs from the TVII, depending on the stars’ compactness and nonlocal parameter. We have also found that for the relatively small value of $\tilde{\beta }$ and the compactness, i.e., $\mathcal{C}\lesssim 0.31$, the causality condition and the DEC are not violated. We have also found that the NGTVII’s effective potential in the interior can be larger and deeper than that of the TVII model, indicating the deceleration of the echo time. Moreover, using the effective potential of NGTVII, the quasinormal mode and gravitational echo are calculated using Bohr-Sommerfeld fitting and solving the time-dependent Reggae-Wheeler equation. We can infer that the NGVTII with the maximum compactness and nonlocal parameter values enables the existence of the ultracompact star with more trapped modes.

We consider the well-posedness of the initial value problem for Einstein-Maxwell theory modified by higher derivative effective field theory corrections. Field redefinitions can be used to bring the leading parity-symmetric 4-derivative corrections to a form which gives second order equations of motion. We show that a recently introduced “modified harmonic” gauge condition can be used to obtain a formulation of these theories which admits a well-posed initial value problem when the higher derivative corrections to the equations of motion are small.

We present an updated data-analysis comparison of the most recent observations of the cosmic microwave background temperature anisotropies and polarization angular power spectra released by four different experiments: the Planck satellite on one side, and the Atacama Cosmology Telescope (ACTPol) and the South Pole Telescope (SPT-3G), combined with the WMAP satellite 9-years observation data in order to be “Planck-independent” on the other side. We investigate in a systematic way 8 extended cosmological models that differ from the baseline $\mathrm{\Lambda }\mathrm{CDM}$ case by the inclusion of many different combinations of additional degrees of freedom, with the aim of finding a viable minimal extended model that can bring all the CMB experiments in agreement. Our analysis provides several hints for anomalies in the CMB angular power spectra in tension with the standard cosmological model that persist even in these multiparameter spaces. This indicates that either significant unaccounted-for systematics in the CMB data are producing biased results or that $\mathrm{\Lambda }\mathrm{CDM}$ is an incorrect/incomplete description of Nature. We conclude that only future independent high-precision CMB temperature and polarization measurements could provide a definitive answer.

The catalog of gravitational-wave events is growing, and so are our hopes for constraining the underlying astrophysics of stellar-mass black-hole mergers by inferring the distributions of, e.g., masses and spins. While conventional analyses parametrize this population with simple phenomenological models, we propose an emulation-based approach that can compare astrophysical simulations against gravitational-wave data. We combine state-of-the-art deep-learning techniques with hierarchical Bayesian inference and exploit our approach to constrain the properties of repeated black-hole mergers from the gravitational-wave events in the most recent LIGO/Virgo catalog. Deep neural networks allow us to (i) construct a flexible single-channel population model that accurately emulates simple parametrized numerical simulations of hierarchical mergers, (ii) estimate selection effects, and (iii) recover the branching ratios of repeated-merger generations. Among our results, we find the following: The distribution of host-environment escape speeds favors values less than $100\mathrm{km}{\mathrm{s}}^{-1}$ but is relatively flat, with around 37% of first-generation mergers retained in their host environments; first-generation black holes are born with a maximum mass that is compatible with current estimates from pair-instability supernovae; there is multimodal substructure in both the mass and spin distributions, which, in our model, can be explained by repeated mergers; and binaries with a higher-generation component make up at least 14% of the underlying population. Though these results are inferred through emulation of a simplified model, the deep-learning pipeline we present is readily applicable to realistic astrophysical simulations.

When rotating primordial black holes evaporate via Hawking radiation, their rotational energy and mass are dissipated with different dynamics. We investigate the effect of these dynamics on the production of dark radiation—in the form of hot gravitons or vector bosons—and noncold dark matter. Although the production of higher spin particles is enhanced while primordial black holes (PBHs) are rotating, we show that the energy density of dark radiation experiences an extra redshift because their emission effectively halts before PBH evaporation completes. We find that taking this effect into account leads to suppression by a factor of $\mathcal{O}(10)$ of $\mathrm{\Delta }{N}_{\mathrm{eff}}$ for maximally rotating black holes as compared to previous results. Using the solution of the Friedmann and Boltzmann equations to accurately calculate the evolution of linear perturbations, we revisit the warm dark matter constraints for light candidates produced by evaporation and how these limits vary over black hole spins. Due to the interplay of enhanced production and late dilution, we obtain that higher spin particles are most affected by these bounds.

For broadband quantum noise reduction of gravitational-wave detectors, a frequency-dependent squeezed vacuum field realized using a filter cavity is the most promising technique and will be implemented in Advanced LIGO and Advanced Virgo in the fourth observing run. To obtain the benefit of frequency-dependent squeezing, the length and alignment of the filter cavity with respect to the squeezed vacuum field must be accurately controlled. To this purpose, a new length and alignment control scheme for a filter cavity, using coherent control sidebands, was suggested [Phys. Rev. D 102, 042003 (2020)]. The coherent control sidebands are already used to control the squeezing angle in squeezed vacuum sources for gravitational-wave detectors. As both the squeezed vacuum field and coherent control sidebands have the same mode-matching conditions and almost the same frequency, the length and alignment of the filter cavity with respect to the squeezed vacuum field can be accurately controlled with this scheme. In this paper, we experimentally demonstrate the new control scheme for a filter cavity with coherent control sidebands. In addition to the conventional filter cavity control with the green field, we succeed in controlling the length of a 300-m filter cavity with coherent control sidebands and reduce the filter cavity length noise (rms) from 6.8 to 2.1 pm.

Semileptonic decay processes of ${\mathrm{\Xi }}_c\to \mathrm{\Xi }\ell {\nu }_{\ell }$ are studied by light-cone QCD sum rules in this paper. The six form factors of ${\mathrm{\Xi }}_c\to \mathrm{\Xi }$ semileptonic transition matrix elements are calculated by this method with the light-cone distribution amplitudes of $\mathrm{\Xi }$ baryon up to twist six. With the six form factors, the absolute branching ratios of ${\mathrm{\Xi }}_c^0\to {\mathrm{\Xi }}^{-}{\ell }^{+}{\nu }_{\ell }$ and ${\mathrm{\Xi }}_c^{+}\to {\mathrm{\Xi }}^0{\ell }^{+}{\nu }_{\ell }$ are calculated by the helicity amplitude formalism of semileptonic differential decay widths. The ratios of absolute branching ratios of electron and muon final-state processes give the proof of lepton flavor universality. Our results are in accordance with the recent experimental and theoretical reports.

The covariant parton model (CPM) is a consequent application of the parton model concept to the nucleon structure. In this model, there is a choice to put quarks either in a pure-spin state or in a mixed-spin state. We show that the mixed-spin version of the CPM does not support the quark-model relations among transverse momentum dependent parton distributions (TMDs) which were shown to hold in a large class of quark models. One can enforce the quark-model relations to be valid in the CPM by imposing a condition which is equivalent to putting the quarks in a pure-spin state. This gives a complementary perspective on the connection of the pure- and mixed-spin state CPM versions and provides a fresh view on the question whether the quark-model relations could be realized in QCD as “approximate relations” with some useful numerical accuracy.

We consider the corrections arising from the SIM(2) invariant realization of Very Special Relativity (VSR) to the energy spectrum of a $C$-invariant Dirac Fermion in a static and homogeneous magnetic field $\mathit{B}$. First, we analyze the case of $\mathit{B}$ parallel to the spatial VSR preferred direction $\mathit{n}$, finding that the expression for the energy spectrum stays the same, except for a mass shift arising from the VSR contribution. Then, we relax the parallelism condition, finding a new equation for the energy spectrum. We solve this equation perturbatively. With a Penning trap’s experiment in mind, we derive the first order VSR corrections to the electron’s $g-2$ factor. Finally, using the most accurate electron’s $g$-factor measurements in Penning trap’s experiments, we obtain an upper bound to the VSR electron mass parameter, and therefore also to the VSR electronic neutrino mass, of $1\mathrm{eV}$. This result does not contradict the possibility for VSR to be the origin of neutrino masses.

The separation of the connected and disconnected sea partons, which were uncovered in the Euclidean path-integral formulation of the hadronic tensor, is accommodated with an extended parametrization of the nonperturbative parton distribution functions in the CT18 global analysis. This is achieved with the help of the distinct small $x$ behaviors of these two sea partons and the constraint from the lattice calculation of the ratio of the strange momentum fraction to that of the $\overline{u}$ or $\overline{d}$ in the disconnected insertion. The whole dataset of CT18 is used in this CT18CS fit. The impact of the recent SeaQuest data on the $\overline{d}(x)-\overline{u}(x)$ distribution of CT18CS is also discussed. The separate momentum fractions for the valence, the connected sea and disconnected sea of $u$ and $d$, the strange and the gluon partons are presented at the input scale $\mu =1.3\mathrm{GeV}$ for the first time. They can be compared term-by-term with systematic error controlled lattice calculations.

We study the effect of a refined electron-photon vertex on the dynamical breaking of chiral symmetry in reduced quantum electrodynamics. We construct an educated ansatz for this vertex that satisfies the required discrete symmetries under parity, time reversal, and charge conjugation operations. Furthermore, it reproduces its asymptotic perturbative limit in the weak coupling regime and ensures the massless electron propagator is multiplicatively renormalizable in its leading logarithmic expansion. Employing this vertex ansatz, we solve the gap equation to compute dynamically generated electron mass whose dependence on the electromagnetic coupling is found to satisfy Miransky scaling law. We also investigate the gauge dependence of this dynamical mass as well as that of the critical coupling above which chiral symmetry is dynamically broken. As a litmus test of our vertex construction, both these quantities are rendered virtually gauge independent within a certain interval of values considered for the covariant gauge parameter.

The current experimental data allow for a sub-TeV colorless weak-singlet scalar or pseudoscalar. If such a singlet field is present together with TeV-range vectorlike top and bottom partners, there is a possibility that the heavy quarks decay dominantly to the singlet state and a third-generation quark, and the singlet state decays to quark and boson pairs. Such a possibility may arise in various models but it has not been explored experimentally, especially in the context of vectorlike-quark searches. We consider some minimal models, covering the possible weak representations of the top and bottom partners, that can be mapped to many well-motivated ultraviolet-complete theories. We chart out the possible interesting and unexplored signatures of the exotic decay of vectorlike quarks and identify benchmark points representing different signal topologies for the high luminosity LHC. We perform a general scan of the parameter space with the relevant direct search bounds and find that large regions, which do not require any fine-tuning, remain open for the unexplored channels. We also perform a simple projection study in the cleanest channel and indicate how other new but experimentally challenging channels can be used to probe more regions of the parameter space.

It is well known that the precise measurement of $H\to \gamma \gamma$ can generate two degenerate parameter spaces of $H\gamma \gamma$ anomalous coupling. We propose to utilize the exclusive Higgs rare decays $H\to \mathrm{\Upsilon }(ns)+\gamma$ to break above mentioned degeneracy and further to constrain the $H\gamma \gamma$ anomalous coupling at the HL-LHC. We demonstrate that the branching ratios of $H\to \mathrm{\Upsilon }(ns)+\gamma$ can be significantly enhanced in the non-SM-like parameter space from $H\to \gamma \gamma$ measurement, due to the destructive interference between the direct and indirect production of $\mathrm{\Upsilon }(ns)$ in the SM. By applying the NRQCD factorization formalism, we calculate the partial decay widths of $H\to \mathrm{\Upsilon }(ns)+\gamma$ at the NLO accuracy of ${\alpha }_s$. We show that it is hopeful to break such degenerate parameter space at the HL-LHC if we can further highly suppress the background and enhance the signal efficiency compared to the ATLAS preliminary simulation.

Practical quantum computing holds clear promise in addressing problems not generally tractable with classical simulation techniques, and some key physically interesting applications are those of real-time dynamics in strongly coupled lattice gauge theories. In this article, we benchmark the real-time dynamics of ${\mathbb{Z}}_2$ and $U(1)$ gauge-invariant plaquette models using noisy intermediate-scale quantum (NISQ) hardware, specifically the superconducting-qubit-based quantum IBM Q computers. We design quantum circuits for models of increasing complexity and measure physical observables such as the return probability to the initial state and locally conserved charges. NISQ hardware suffers from significant decoherence and a corresponding difficulty to interpret the results. We demonstrate the use of hardware-agnostic error mitigation techniques, such as circuit folding methods implemented via the Mitiq package, and we show what they can achieve within the quantum volume restrictions for the hardware. Our study provides insight into the choice of Hamiltonians, the construction of circuits, and the utility of error mitigation methods to devise large-scale quantum computation strategies for lattice gauge theories.

Quantum computing holds the promise of substantially speeding up computationally expensive tasks, such as solving optimization problems over a large number of elements. In high-energy collider physics, quantum-assisted algorithms might accelerate the clustering of particles into jets. In this study, we benchmark quantum annealing strategies for jet clustering based on optimizing a quantity called “thrust” in electron-positron collision events. We find that quantum annealing yields similar performance to exact classical approaches and classical heuristics, after tuning the annealing parameters. Without tuning, comparable performance can be obtained through a hybrid quantum/classical approach.

Inspired by a recent study by Iancu, Mueller, and Triantafyllopoulos [Phys. Rev. Lett. 128, 202001 (2022)], we propose semi-inclusive diffractive deep inelastic scattering (SIDDIS) to investigate the gluon tomography in the nucleon and nuclei at small $x$. The relevant diffractive quark and gluon parton distribution functions (DPDFs) can be computed in terms of the color dipole $S$-matrices in the fundamental and adjoint representations, respectively.