In this paper, we holographically study the renormalization group (RG) flow in a three-dimensional Einstein-dilaton gravity with a specific scalar potential, which permits several different types of the RG flow with nontrivial beta functions. By using the intrinsic parameter of the potential, we classify the possible holographic RG flows and examine their physical features. Using the Ryu-Takayanagi formulation, furthermore, we investigate how the $c$ function of the entanglement entropy behaves along with the RG flow numerically. We show that the entanglement $c$ function monotonically decreases even in the cases with a nontrivial beta function. For checking the consistency, we also compare the result of the entanglement entropy with the $c$ function derived from the holographic renormalization procedure.

Using the fact that theories of gravity with asymptotically three-dimensional anti–de Sitter geometries have dual descriptions as two-dimensional conformal field theories (CFTs), we present the first study in field theory of the thermodynamic volume of various black hole solutions. We explain in general two-dimensional CFT terms why the presence of a thermodynamic volume can render certain black hole solutions “superentropic.” Superentropicity simply results from the fact that the Cardy formula, which gives the gravitational Bekenstein-Hawking entropy, can overcount the CFT entropy. The examples of charged Bañados, Teitelbiom, and Zanelli (BTZ) black holes and generalized exotic BTZ black holes are described. These observations help explain why the specific heat at constant volume can signal the instability of such solutions, as recently conjectured.

In this paper we continue earlier investigations [F. Beyer et al., Classical Quantum Gravity 34, 205014 (2017); F. Beyer et al., Classical Quantum Gravity 36, 175005 (2019); K. Csukás and I. Rácz, arXiv:1911.02900] of evolutionary formulations of the Einstein vacuum constraint equations originally introduced by Rácz. Motivated by the strong evidence from these works that the resulting vacuum initial data sets are generically not asymptotically flat we analyze the asymptotics of the solutions of a modified formulation by a combination of analytical and numerical techniques. We conclude that the vacuum initial data sets generated with this new formulation are generically asymptotically flat.

In this paper, we consider wormhole geometries in the context of the teleparallel equivalent of general relativity (TEGR) as well as $f(T)$ gravity. The TEGR is an alternative geometrical formulation of Einstein’s general relativity, where modified teleparallel gravity or $f(T)$ gravity has been invoked as an alternative approach for explaining an accelerated expansion of the universe. We present the analytical solutions under the assumption of spherical symmetry and the existence of a conformal Killing vectors to proceed a more systematic approach in searching for exact wormhole solutions. More preciously, the existence of a conformal symmetry places restrictions on the model. Considering the field equations with a diagonal tetrad and anisotropic distribution of the fluid, we study the properties of traversable wormholes in TEGR that violates the weak and the null energy conditions at the throat and its vicinity. In the second part, wormhole solutions are constructed in the framework of $f(T)$ gravity, where $T$ represents torsion scalar. As a consistency check, we also discuss the behavior of energy conditions with a viable power-law $f(T)$ model and the corresponding shape functions. In addition, a wide variety of solutions are deduced by considering a linear equation of state relating the density and pressure, for the isotropic and anisotropic pressure, independently of the shape functions, and various phantom wormhole geometries are explored.

The classical soft graviton theorem gives an expression for the spectrum of low frequency gravitational radiation, emitted during a classical scattering process, in terms of the trajectories and spin angular momenta of ingoing and outgoing objects, including hard radiation. This has been proved to subleading order in the expansion in powers of the soft frequency by taking the classical limit of the quantum soft graviton theorem. In this paper we give a direct proof of this result by analyzing the classical equations of motion of a generic theory of gravity coupled to interacting matter in space-time dimensions larger than four.

Using on-shell amplitude methods, we derive a rotating black hole solution in a generic theory of Einstein gravity with additional terms cubic in the Riemann tensor. We give an explicit expression for the metric in Einsteinian cubic gravity and low-energy effective string theory, which correctly reproduces the previously discovered solutions in the zero-angular-momentum limit. We show that at first order in the coupling, the classical potential can be written to all orders in spin as a differential operator acting on the nonrotating potential, and we comment on the relation to the Janis-Newman algorithm. Furthermore, we derive the classical impulse and scattering angle for such a black hole and comment on the phenomenological interest of such quantities.

Large scale density modes are difficult to measure because they are sensitive to systematic observational errors in galaxy surveys, but we can study them indirectly by observing their impact on small scale perturbations. Cosmological perturbation theory predicts that second-order density inhomogeneities are a convolution of a short- and a long-wavelength mode. This arises physically because small scale structures grow at different rates depending on the large scale environment in which they reside. This induces an off diagonal term in the two-point statistics in Fourier space that we use as the basis for a quadratic estimator for the large scale field. We demonstrate that this quadratic estimator works well on an N-body simulation of size $(2.5h^{-1}\mathrm{Gpc}{)}^3$. In particular, the quadratic estimator successfully reconstructs the long-wavelength modes using only small-scale information. This opens up novel opportunities to study structure on the largest observable scales.

In this paper we explore possible extensions of interacting dark energy cosmologies, where dark energy and dark matter interact nongravitationally with one another. In particular, we focus on the neutrino sector, analyzing the effect of both neutrino masses and the effective number of neutrino species. We consider the Planck 2018 legacy release data combined with several other cosmological probes, finding no evidence for new physics in the dark radiation sector. The current neutrino constraints from cosmology should therefore be regarded as robust, as they are not strongly dependent on the dark sector physics, once all the available observations are combined. Namely, we find a total neutrino mass $M_{\nu }<0.15\mathrm{eV}$ and a number of effective relativistic degrees of freedom $N_{\mathrm{eff}}=3.03_{-0.33}^{+0.33}$, both at 95% C.L., which are close to those obtained within the $\mathrm{\Lambda }\mathrm{CDM}$ cosmology, $M_{\nu }<0.12\mathrm{eV}$ and $N_{\mathrm{eff}}=3.00_{-0.35}^{+0.36}$, for the same data combination.

We use six tilted spatially flat and untilted nonflat dark energy cosmological models in analyses of South Pole Telescope polarization (SPTpol) cosmic microwave background (CMB) data, alone and in combination with Planck 2015 CMB data and non-CMB data, namely, the Pantheon type Ia supernovae apparent magnitudes, a collection of baryon acoustic oscillation data points, Hubble parameter measurements, and growth rates. Although the cosmological models that best fit the Planck CMB and non-CMB data do not provide good fits to the SPTpol data, with the ${\chi }^2$’s exceeding the expected value, given the uncertainties, in each model the cosmological parameter constraints from the SPTpol data and from the Planck CMB and non-CMB data are largely mutually consistent. When the smaller angular scale SPTpol data are used jointly with either the Planck data alone or with the Planck CMB and the non-CMB data to constrain untilted nonflat models, spatially closed models remain favored over their corresponding flat limits. When used in conjunction with Planck data, non-CMB data (baryon acoustic oscillation measurements in particular, from six experiments) have significantly more constraining power than the SPTpol data.

We present a novel integrator based on normalizing flows which can be used to improve the unweighting efficiency of Monte Carlo event generators for collider physics simulations. In contrast to machine learning approaches based on surrogate models, our method generates the correct result even if the underlying neural networks are not optimally trained. We exemplify the new strategy using the example of Drell-Yan type processes at the LHC, both at leading and partially at next-to-leading order QCD.

We have witnessed in the past decade the observation of a puzzling cosmic-ray excess at energies larger than 10 GeV. The AMS-02 data published this year have new ingredients such as the bump around 300 GeV followed by a drop at 800 GeV, as well as smaller error bars. Adopting the background used by the AMS-02 Collaboration in their analysis, one can conclude that previous explanations to the new AMS-02 such as one component annihilating and decaying dark matter as well as pulsars seem to fail at reproducing the data. Here, we show that in the right-handed neutrino portal might reside the answer. We discuss a decaying two-component dark matter scenario where the two-body decay products are right-handed neutrinos that have their decay pattern governed by the type-I seesaw mechanism. This setup provides a very good fit to the data; for example, a conservative approach including just statistical uncertainties leads to ${\chi }^2/\mathrm{DOF}\sim 2.3$ for $m_{D{M}_1}=2150\mathrm{GeV}$ with ${\tau }_1=3.78\times {10}^{26}$ s and $m_{D{M}_2}=300$ with ${\tau }_2=5.0\times {10}^{27}\mathrm{s}$ for $M_N=10\mathrm{GeV}$, and, in an optimistic case, including systematic uncertainties, we find ${\chi }^2/\mathrm{DOF}\sim 1.12$, for $M_N=10\mathrm{GeV}$, with $m_{D{M}_1}=2200\mathrm{GeV}$ with ${\tau }_1=3.8\times {10}^{26}\mathrm{s}$ and $m_{D{M}_2}=323\mathrm{GeV}$ with ${\tau }_2=1.68\times {10}^{27}\mathrm{s}$.

Diffractive deeply virtual Compton scattering (DiDVCS) is the process ${\gamma }^{*}(-Q^2)+N\to {\rho }^0+{\gamma }^{*}(Q^{\prime 2})+N^{\prime }$, where N is a nucleon or light nucleus, in the kinematical regime of large rapidity gap between the ${\rho }^0$ and the final photon-nucleus system, and in the generalized Bjorken regime where both photon virtualities $Q^2$ and $Q^{\prime 2}$ are large. We show that this process has the unique virtue of combining the large diffractive cross sections at high energy with the tomographic ability of deeply virtual Compton scattering to scrutinize the quark and gluon content of nucleons and light nuclei. Its study at an electron-ion collider will enlighten the internal structure of hadrons.

In the quark-gluon plasma, it is well known that the evolution of quarkonia is affected by the screening of the interaction between the quark and the antiquark. In addition, an exchange of energy and color with the surrounding medium can be included via the incorporation of noise terms in the evolution Hamiltonian. For noise correlated locally in time, these dynamics were studied in a simple setting by S. Kajimoto, Y. Akamatsu, M. Asakawa, and A. Rothkopf [Phys. Rev. D 97, 014003 (2018)]. We extend this calculation by considering non-Abelian dynamics for a three-dimensional wave function. We also propose a modification of the noise correlation, allowing it to have a finite correlation in time with the motivation to include long-lived gluonic correlations. We find that in both cases the results differ significantly from solutions of rate equations.

Precise extractions of ${\alpha }_s$ from $\tau \to (\mathrm{hadrons})+{\nu }_{\tau }$ and from $e^{+}{e}^{-}\to (\text{hadrons})$ below the charm threshold rely on finite energy sum rules where the experimental side is given by integrated spectral function moments. Here we study the renormalons that appear in the Borel transform of polynomial moments in the large-${\beta }_0$ limit and in full QCD. In large ${\beta }_0$, we establish a direct connection between the renormalons and the perturbative behavior of moments often employed in the literature. The leading IR singularity is particularly prominent and is behind the fate of moments whose perturbative series are unstable, while those with good perturbative behavior benefit from partial cancellations of renormalon singularities. The conclusions can be extended to QCD through a convenient scheme transformation to the $C$ scheme together with the use of a modified Borel transform which make the results particularly simple; the leading IR singularity becomes a simple pole, as in large ${\beta }_0$. Finally, for the moments that display good perturbative behavior, we discuss an optimized truncation based on renormalization scheme (or scale) variation. Our results allow for a deeper understanding of the perturbative behavior of integrated spectral function moments and provide theoretical support for low-$Q^2$ ${\alpha }_s$ determinations.

Scale invariance (SI) can in principle be realized in the elastic response of solid materials. There are two basic options: that SI is a manifest symmetry or that it is spontaneously broken. The manifest case corresponds physically to the existence of a nontrivial infrared fixed point with phonons among its degrees of freedom. We use simple bottom-up $\mathrm{AdS}/\mathrm{CFT}$ constructions to model this case. We characterize the types of possible elastic response and discuss how the sound speeds can be realistic, that is, sufficiently small compared to the speed of light. We also study the spontaneously broken case using effective field theory (EFT) methods. We present a new one-parameter family of nontrivial EFTs that includes the previously known “conformal solid” as a particular case as well as others which display small sound speeds. We also point out that an emergent Lorentz invariance at low energies could affect by order-one factors the relation between sound speeds and elastic moduli.

We investigate the consequences of different regularizations and ambiguities in loop cosmological models on the predictions in the scalar and tensor primordial spectrum of the cosmic microwave background using the dressed metric approach. Three models, standard loop quantum cosmology (LQC), and two modified loop quantum cosmologies (mLQC-I and mLQC-II) arising from different regularizations of the Lorentzian term in the classical Hamiltonian constraint are explored for chaotic inflation in spatially flat Friedmann-Lemaître-Robertson-Walker (FLRW) universe. In each model, two different treatments of the conjugate momentum of the scale factor are considered. The first one corresponds to the conventional treatment in dressed metric approach, and the second one is inspired from the hybrid approach which uses the effective Hamiltonian constraint. For these two choices, we find the power spectrum to be scale-invariant in the ultraviolet regime for all three models, but there is at least a 10% relative difference in amplitude in the infrared and intermediate regimes. All three models result in significant differences in the latter regimes. In mLQC-I, the magnitude of the power spectrum in the infra-red regime is of the order of Planck scale irrespective of the ambiguity in conjugate momentum of the scale factor. The relative difference in the amplitude of the power spectrum between LQC and mLQC-II can be as large as 50% throughout the infrared and intermediate regimes. Differences in amplitude due to regularizations and ambiguities turn out to be small in the ultraviolet regime.

We present a holographic analysis of diffractive photoproducton of charmonium $J/\psi$ and upsilonium $\mathrm{\Upsilon }$ on a proton, considered as a bulk Dirac fermion, for all ranges of $\sqrt{s}$, i.e., from near threshold to very high energy. Using the bulk wave functions of the proton and vector mesons, within holographic QCD, and employing Witten diagrams in the bulk, we compute the diffractive photoproduction amplitude of $J/\psi$ and $\mathrm{\Upsilon }$. The holographic amplitude shows elements of the strictures of vector meson dominance. It is dominated by the exchange of a massive graviton or $2^{++}$ glueball resonances near threshold, and its higher spin-j counterparts that reggeize at higher energies. Both the differential and total cross sections are controlled by the gravitational form factor $A(t)$, and compare well to the recent results reported by the GlueX Collaboration near threshold and the world data at large $\sqrt{s}$. The holographic gravitational form factors, including the D-term, which is due to the exchange of massive spin-0 glueballs, are in good agreement with lattice simulations. We use it to extract the holographic pressure and shear forces inside the proton. Finally, using a pertinent integral representation of the holographic gravitational form factor $A(t)$ near threshold, and its Pomeron counterpart way above threshold, we extract the generalized parton distribution of gluons inside the proton at different resolutions.

Inspired by the recent proposal for the quantum effective dynamics of the Schwarzschild spacetime given in [1], we investigate the effective dynamics of the loop quantized Janis-Newman-Winicour (JNW) spacetime which is an extension of the Schwarzschild spacetime with an extra minimally coupled massless scalar field. Two parameters are introduced in order to regularize the Hamiltonian constraint in the quantum effective dynamics. These two parameters are assumed to be Dirac observables when the effective dynamics is solved. By carefully choosing appropriate conditions for these two parameters, we completely determine them, and the resulted new effective description of the JNW spacetime leads to a well-behaved quantum dynamics which on one hand resolves the classical singularities, and on the other hand, agrees with the classical dynamics in the low curvature region.

We discuss what happens when a field that receives an Aharonov-Bohm (AB) phase develops a vacuum expectation value (VEV), using the example of an Alice string in a $U(1)\times SU(2)$ gauge theory coupled with complex triplet scalar fields. We introduce scalar fields belonging to the doublet representation of $SU(2)$, charged or chargeless under the $U(1)$ gauge symmetry, that receives an AB phase around the Alice string. When the doublet develops a VEV, the Alice string becomes a global string in the absence of the interaction depending on the relative phase between the doublet and triplet, while in the presence of such an interaction the Alice string is confined by a soliton or domain wall, and therefore the spatial rotation around the string is spontaneously broken. We call such an object induced by an AB phase an “AB defect,” and argue that such a phenomenon is ubiquitous in various systems.

In this paper, we discuss some specific features for the stress-energy tensor of vacuum nonlinear electrodynamics and based on these features we propose the inequalities which in form are close to the energy conditions widely used in general relativity and which can be interpreted as their possible nonlinear extension. The modified energy conditions were verified for the perfect fluid and real scalar field with an arbitrary coupling to the kinetic term.