We explore charged black hole solutions in Einstein-Gauss-Bonnet gravity in five dimensions, with a charged scalar hair. We interpret such hairy black holes as the final state of the superradiant instability previously reported for this system. We explore the relation of the hairy black hole solutions with the nonbackreacting quasibound states and scalar clouds, as well as with the boson star solutions.

The nonequilibrium attractors of systems undergoing Gubser flow within relativistic kinetic theory are studied. In doing so we employ well-established methods of nonlinear dynamical systems which rely on finding the fixed points, investigating the structure of the flow diagrams of the evolution equations, and characterizing the basin of attraction using a Lyapunov function near the stable fixed points. We obtain the attractors of anisotropic hydrodynamics, Israel-Stewart (IS) and transient fluid (DNMR) theories and show that they are indeed nonplanar and the basin of attraction is essentially three dimensional. The attractors of each hydrodynamical model are compared with the one obtained from the exact Gubser solution of the Boltzmann equation within the relaxation time approximation. We observe that the anisotropic hydrodynamics is able to match up to high numerical accuracy the attractor of the exact solution while the second-order hydrodynamical theories fail to describe it. We show that the IS and DNMR asymptotic series expansions diverge and use resurgence techniques to perform the resummation of these divergences. We also comment on a possible link between the manifold of steepest descent paths in path integrals and the basin of attraction for the attractors via Lyapunov functions that opens a new horizon toward an effective field theory description of hydrodynamics. Our findings indicate that the reorganization of the expansion series carried out by anisotropic hydrodynamics resums the Knudsen and inverse Reynolds numbers to all orders and thus, it can be understood as an effective theory for the far-from-equilibrium fluid dynamics.

The vacuum solutions around a spherically symmetric and static object in the Starobinsky model are studied with a perturbative approach. The differential equations for the components of the metric and the Ricci scalar are obtained and solved by using the method of matched asymptotic expansions. The presence of higher order terms in this gravity model leads to the formation of a boundary layer near the surface of the star allowing the accommodation of the extra boundary conditions on the Ricci scalar. Accordingly, the metric can be different from the Schwarzschild solution near the star depending on the value of the Ricci scalar at the surface of the star while matching the Schwarzschild metric far from the star.

Gravitational wave astronomy has set in motion a scientific revolution. To further enhance the science reach of this emergent field of research, there is a pressing need to increase the depth and speed of the algorithms used to enable these ground-breaking discoveries. We introduce Deep Filtering—a new scalable machine learning method for end-to-end time-series signal processing. Deep Filtering is based on deep learning with two deep convolutional neural networks, which are designed for classification and regression, to detect gravitational wave signals in highly noisy time-series data streams and also estimate the parameters of their sources in real time. Acknowledging that some of the most sensitive algorithms for the detection of gravitational waves are based on implementations of matched filtering, and that a matched filter is the optimal linear filter in Gaussian noise, the application of Deep Filtering using whitened signals in Gaussian noise is investigated in this foundational article. The results indicate that Deep Filtering outperforms conventional machine learning techniques, achieves similar performance compared to matched filtering, while being several orders of magnitude faster, allowing real-time signal processing with minimal resources. Furthermore, we demonstrate that Deep Filtering can detect and characterize waveform signals emitted from new classes of eccentric or spin-precessing binary black holes, even when trained with data sets of only quasicircular binary black hole waveforms. The results presented in this article, and the recent use of deep neural networks for the identification of optical transients in telescope data, suggests that deep learning can facilitate real-time searches of gravitational wave sources and their electromagnetic and astroparticle counterparts. In the subsequent article, the framework introduced herein is directly applied to identify and characterize gravitational wave events in real LIGO data.

A technique for translating the classical scattering function of two gravitationally interacting bodies into a corresponding (effective one-body) Hamiltonian description has been recently introduced [Phys. Rev. D 94, 104015 (2016)]. Using this technique, we derive, for the first time, to second-order in Newton’s constant (i.e. one classical loop) the Hamiltonian of two point masses having an arbitrary (possibly relativistic) relative velocity. The resulting (second post-Minkowskian) Hamiltonian is found to have a tame high-energy structure which we relate both to gravitational self-force studies of large mass-ratio binary systems, and to the ultra high-energy quantum scattering results of Amati, Ciafaloni and Veneziano. We derive several consequences of our second post-Minkowskian Hamiltonian: (i) the need to use special phase-space gauges to get a tame high-energy limit; and (ii) predictions about a (rest-mass independent) linear Regge trajectory behavior of high-angular-momenta, high-energy circular orbits. Ways of testing these predictions by dedicated numerical simulations are indicated. We finally indicate a way to connect our classical results to the quantum gravitational scattering amplitude of two particles, and we urge amplitude experts to use their novel techniques to compute the two-loop scattering amplitude of scalar masses, from which one could deduce the third post-Minkowskian effective one-body Hamiltonian.

The dynamics of compact binary systems at the fourth post-Newtonian (4PN) approximation of general relativity has been recently completed in a self-consistent way. In this paper, we compute the ten Poincaré constants of the motion and present the equations of motion in the frame of the center of mass (CM), together with the corresponding CM Lagrangian, conserved energy and conserved angular momentum. Next, we investigate the reduction of the CM dynamics to the case of quasi-circular orbits. The non local (in time) tail effect at the 4PN order is consistently included, as well as the relevant radiation-reaction dissipative contributions to the energy and angular momentum.

We show that $R^2$ gravity coupled conformally to scalar fields is equivalent to the real bosonic sector of $\mathrm{SU}(\mathrm{N},1)/\mathrm{SU}(\mathrm{N})\times \mathrm{U}(1)$ no-scale supergravity, where the conformal factor can be identified with the Kähler potential, and we review the construction of Starobinsky-like models of inflation within this framework.

We study large-scale inhomogeneous perturbations and instabilities of interacting dark-energy models. Past analysis of large-scale perturbative instabilities has shown that we can only test interacting dark-energy models with observational data when their parameter ranges are either $w_x\ge -1$ and $\xi \ge 0$, or $w_x\le -1$ and $\xi \le 0$, where $w_x$ is the dark-energy equation of state and $\xi$ is a coupling parameter governing the strength and direction of the energy transfer. We show that by adding a factor ($1+w_x$) to the background energy transfer, the whole parameter space can be tested against all the data, and thus, the instabilities in such interaction models can be removed. We test three classes of interaction models using the latest astronomical data from the CMB, supernovae, baryon acoustic oscillations, redshift-space distortions, weak lensing, cosmic chronometers, and the local Hubble constant. Precise constraints are found. Our analysis shows that a very small but nonzero deviation from pure $\mathrm{\Lambda }$-cosmology is suggested by the observational data, while the no-interaction scenario can be recovered at the 68.3% confidence level. In particular, for three interacting dark-energy (IDE) models, identified as IDE 1, IDE 2, and IDE 3, the 68.3% confidence-level constraints on the interaction coupling strengths are $\xi =0.0360_{-0.0360}^{+0.0091}$ (IDE 1), $\xi =0.0433_{-0.0433}^{+0.0062}$ (IDE 2), $\xi =0.1064_{-0.1064}^{+0.0437}$ (IDE 3). In addition, we find that the dark-energy equation of state tends towards the phantom region. Taking the 68.3% confidence-level constraints, $w_x=-1.0230_{-0.0257}^{+0.0329}$ (IDE 1), $w_x=-1.0247_{-0.0302}^{+0.0289}$ (IDE 2), and $w_x=-1.0275_{-0.0318}^{+0.0228}$ (IDE 3). However, the possibility of $w_x>-1$ is also not rejected by the astronomical data employed in this analysis. Moreover, we find in all interaction models that, as the value of the Hubble constant decreases, the behavior of the dark-energy equation of state shifts from a phantom to a quintessence type with its equation of state very close to that of a simple cosmological constant at the present time. Finally, we compare the observational estimations of the coupling strength imposed on some interaction models studied in this work with the past constraints obtained on them for different regions of the dark-energy equation of state.

A correlation between the secondary cosmic ray flux and the near-earth electric field intensity, measured during thunderstorms, has been found by analyzing the data of the ARGO-YBJ experiment, a full coverage air shower array located at the Yangbajing Cosmic Ray Laboratory (4300 m a. s. l., Tibet, China). The counting rates of showers with different particle multiplicities ($m=1$, 2, 3, and $\ge 4$) have been found to be strongly dependent upon the intensity and polarity of the electric field measured during the course of 15 thunderstorms. In negative electric fields (i.e., accelerating negative charges downwards), the counting rates increase with increasing electric field strength. In positive fields, the rates decrease with field intensity until a certain value of the field ${\mathrm{EF}}_{\min }$ (whose value depends on the event multiplicity), above which the rates begin increasing. By using Monte Carlo simulations, we found that this peculiar behavior can be well described by the presence of an electric field in a layer of thickness of a few hundred meters in the atmosphere above the detector, which accelerates/decelerates the secondary shower particles of opposite charge, modifying the number of particles with energy exceeding the detector threshold. These results, for the first time to our knowledge, give a consistent explanation for the origin of the variation of the electron/positron flux observed for decades by high altitude cosmic ray detectors during thunderstorms.

“Curvepole (2,0)-theory” is a deformation of the (2,0)-theory with nonlocal interactions. A curvepole is defined as a two-dimensional generalization of a dipole. It is an object of fixed two-dimensional shape of which the boundary is a charged curve that interacts with a 2-form gauge field. Curvepole theory was previously only defined indirectly via M-theory. Here, we propose a supersymmetric Lagrangian, constructed explicitly up to quartic terms, for an “Abelian” curvepole theory, which is an interacting deformation of the free (2,0) tensor multiplet. This theory contains fields of which the quanta are curvepoles (i.e., fixed-shape strings). Supersymmetry is preserved (at least up to quartic terms) if the shape of the curvepoles is (two-dimensional) planar. This nonlocal six-dimensional quantum field theory may also serve as a UV completion for certain (local) five-dimensional gauge theories.

The ongoing observations of merging black holes by the instruments of the fledging gravitational wave astronomy has opened the way for testing the general-relativistic Kerr black hole metric and, at the same time, for probing the existence of more speculative horizonless ultracompact objects. In this paper we quantify the difference that these two classes of objects may exhibit in the post-merger ringdown signal. By considering rotating systems in general relativity and assuming an eikonal limit and a third-order Hartle-Thorne slow-rotation approximation, we provide the first calculation of the early ringdown frequency and damping time as a function of the body’s multipolar structure. Using the example of a gravastar, we show that the main ringdown signal may differ by as much as a few percent with respect to that of a Kerr black hole, a deviation that could be probed by near-future Advanced LIGO/Virgo searches.

The six-year data set of high-energy starting events (HESEs) at IceCube indicates a spectrum of astrophysical neutrinos much softer than expected from the Fermi shock acceleration mechanism. On the other hand, IceCube’s up-going muon neutrino data set and Fermi-LAT’s gamma-ray spectrum point to an $E^{-2}$ neutrino spectrum. If the HESE data above 200 TeV are fit with the latter flux, an excess at lower energies ensues, which then suggests a multicomponent spectrum. We show that the HESE data set can be explained by a single $E^{-2}$ power-law neutrino flux from a muon-damped $p\gamma$ source if neutrino interactions are modified by $CPT$ violation. The low-energy excess is naturally explained by the pileup of events from superluminal neutrino decay, and there is no cutoff at high energies due to the contribution of subluminal antineutrinos. The best-fit scenario with $CPT$ violation also predicts the observation of Glashow resonance events in the near future.

At proposed future hadron colliders and in the coming years at the LHC, top quarks will be produced at genuinely multi-TeV energies. Top-tagging at such high energies forces us to confront several new issues in terms of detector capabilities and jet physics. Here, we explore these issues in the context of some simple JHU/CMS-type declustering algorithms and the $N$-subjettiness jet-shape variable ${\tau }_{32}$. We first highlight the complementarity between the two tagging approaches at particle level with respect to discriminating top-jets against gluons and quarks, using multivariate optimization scans. We then introduce a basic fast detector simulation, including electromagnetic calorimeter showering patterns determined from GEANT. We consider a number of tricks for processing the fast detector output back to an approximate particle-level picture. Re-optimizing the tagger parameters, we demonstrate that the inevitable losses in discrimination power at very high energies can typically be ameliorated. For example, percent-scale mistag rates might be maintained even in extreme cases where an entire top decay would sit inside of one hadronic calorimeter cell and tracking information is completely absent. We then study three novel physics effects that will come up in the multi-TeV energy regime: gluon radiation off of boosted top quarks, mistags originating from $g\to t\overline{t}$, and mistags originating from $q\to (W/Z)q$ collinear electroweak splittings with subsequent hadronic decays. The first effect, while nominally a nuisance, can actually be harnessed to slightly improve discrimination against gluons. The second effect can lead to effective $O(1)$ enhancements of gluon mistag rates for tight working points. And the third effect, while conceptually interesting, we show to be of highly subleading importance at all energies.

We study all-optical signatures of the effective nonlinear couplings among electromagnetic fields in the quantum vacuum, using the collision of two focused high-intensity laser pulses as an example. The experimental signatures of quantum vacuum nonlinearities are encoded in signal photons, whose kinematic and polarization properties differ from the photons constituting the macroscopic laser fields. We implement an efficient numerical algorithm allowing for the theoretical investigation of such signatures in realistic field configurations accessible in experiment. This algorithm is based on a vacuum emission scheme and can readily be adapted to the collision of more laser beams or further involved field configurations. We solve the case of two colliding pulses in full $3+1$-dimensional spacetime and identify experimental geometries and parameter regimes with improved signal-to-noise ratios.

Spectral features in LHC dileptonic events may signal radiative corrections coming from new degrees of freedom, notably dark matter and mediators. Using simplified models, and under a set of simplifying assumptions, we show how these features can reveal the fundamental properties of the dark sector, such as self-conjugation, spin and mass of dark matter, and the quantum numbers of the mediator. Distributions of both the invariant mass $m_{\ell \ell }$ and the Collins-Soper scattering angle $\cos {\theta }_{\mathrm{CS}}$ are studied to pinpoint these properties. We derive constraints on the models from LHC measurements of $m_{\ell \ell }$ and $\cos {\theta }_{\mathrm{CS}}$, which are competitive with direct detection and $\text{jets}+\mathrm{MET}$ searches. We find that in certain scenarios the $\cos {\theta }_{\mathrm{CS}}$ spectrum provides the strongest bounds, underlining the importance of scattering angle measurements for nonresonant new physics.

The invisible variant axion model is one of the very attractive models which solves the strong $CP$ problem but does not provoke the domain wall problem. At the electroweak scale, this model requires at least two Higgs doublets, one of which carries a nonzero Peccei-Quinn (PQ) charge and the other is neutral. We consider a scenario where only the right-handed top quark is charged under the PQ symmetry and couples with the PQ-charged Higgs doublet. As a general prediction of this model, the top quark can decay to the observed standard model-like Higgs boson $h$ and the charm or up quark, $t\to hc/u$, which recently exhibited slight excesses at LHC run-I and run-II and will soon be testable at the LHC run-II. If the rare top decay excess stays at the observed central value, we show that $\tan \beta \sim 1$ or smaller is preferred by the Higgs data. The chiral nature of the Higgs flavor-changing interaction is a distinctive feature of this model and testable using the angular distribution of the $t\to ch$ decays at the LHC.

Recently, some reformulations of the Yang-Mills theory inspired by the Cho-Faddeev-Niemi decomposition have been developed in order to understand confinement from the viewpoint of the dual superconductivity. In this paper we focus on the reformulated $SU(N)$ Yang-Mills theory in the minimal option with $U(N-1)$ stability group. Despite existing numerical simulations on the lattice we perform the perturbative analysis to one-loop level as a first step towards the nonperturbative analytical treatment. First, we give the Feynman rules and calculate all renormalization factors to obtain the standard renormalization group functions to one-loop level in light of the renormalizability of this theory. Then we introduce a mixed gluon-ghost composite operator of mass dimension 2 and show the Bechi-Rouet-Stora-Tyutin invariance and the multiplicative renormalizability. Armed with these results, we argue the existence of the mixed gluon-ghost condensate by means of the so-called local composite operator formalism, which leads to various interesting implications for confinement as shown in preceding works.

I present higher-order corrections from soft-gluon emission for the associated production of a top quark with a $Z$ boson via anomalous $t\text{−}q\text{−}Z$ couplings at LHC energies. Approximate next-to-next-to-leading order (aNNLO) double-differential cross sections are derived from soft-gluon resummation at next-to-leading-logarithm accuracy. The total $tZ$ production cross sections and the top-quark transverse-momentum and rapidity distributions are calculated at aNNLO for various LHC energies. It is shown that the soft-gluon corrections are dominant and large for this process.

Inspired by the five newly observed ${\mathrm{\Omega }}_c^0$ states by the LHCb detector, we study the ${\mathrm{\Omega }}_c^0$ states as the $S$-wave molecular pentaquarks with $I=0$, $J^P={\frac{1}{2}}^{-}$, ${\frac{3}{2}}^{-}$, and ${\frac{5}{2}}^{-}$ by solving the renormalization group method equation in the framework of the chiral quark model. Both the energies and the decay widths are obtained in this work. Our results suggest that ${\mathrm{\Omega }}_c(3119{)}^0$ can be explained as an $S$-wave resonance state of $\mathrm{\Xi }D$ with $J^P={\frac{1}{2}}^{-}$, and the decay channels are the $S$-wave ${\mathrm{\Xi }}_c\overline{K}$ and ${\mathrm{\Xi }}_c^{\prime }\overline{K}$. Other reported ${\mathrm{\Omega }}_c^0$ states cannot be obtained in our present calculation. Another ${\mathrm{\Omega }}_c^0$ state with much higher mass 3533 MeV with $J^P={\frac{5}{2}}^{-}$ is also obtained. In addition, the calculation is extended to the ${\mathrm{\Omega }}_b^0$ states, and results similar to those of ${\mathrm{\Omega }}_c^0$ are obtained.

In a wide class of cosmological models, a positive cosmological constant drives cosmological evolution toward an asymptotically de Sitter phase. Here we connect this behavior to the increase of entropy over time, based on the idea that de Sitter spacetime is a maximum-entropy state. We prove a cosmic no-hair theorem for Robertson-Walker and Bianchi I spacetimes that admit a Q-screen (“quantum” holographic screen) with certain entropic properties: If generalized entropy, in the sense of the cosmological version of the generalized second law conjectured by Bousso and Engelhardt, increases up to a finite maximum value along the screen, then the spacetime is asymptotically de Sitter in the future. Moreover, the limiting value of generalized entropy coincides with the de Sitter horizon entropy. We do not use the Einstein field equations in our proof, nor do we assume the existence of a positive cosmological constant. As such, asymptotic relaxation to a de Sitter phase can, in a precise sense, be thought of as cosmological equilibration.