By using a method improved with a generalized optical metric, the deflection of light for an observer and source at finite distance from a lens object in a stationary, axisymmetric and asymptotically flat spacetime has been recently discussed [Ono et al. Phys. Rev. D 96, 104037 (2017)]. By using this method, in the weak field approximation, we study the deflection angle of light for an observer and source at finite distance from a rotating Teo wormhole, especially by taking account of the contribution from the geodesic curvature of the light ray in a space associated with the generalized optical metric. Our result of the deflection angle of light is compared with a recent work on the same wormhole but limited within the asymptotic source and observer [Jusufi, Övgün, Phys. Rev. D 97, 024042 (2018)], in which they employ another approach proposed by Werner with using the Nazim’s osculating Riemannian construction method via the Randers-Finsler metric. We show that the two different methods give the same result in the asymptotic limit. We obtain also the corrections to the deflection angle due to the finite distance from the rotating wormhole.

We give a novel definition of gravitational energy for an arbitrary theory of gravity including quadratic-curvature corrections to Einstein’s equations. We focus on the theory in four dimensions, in the presence of a negative cosmological constant, and with asymptotically anti–de Sitter (AdS) boundary conditions. As a first example, we compute the gravitational energy and angular momentum of Schwarzschild-AdS black holes, for which we obtain results consistent with previous computations performed using different methods. However, our method is qualitatively different due to the fact that it is intrinsically nonlinear. It relies on the idea of adding to the gravity action topological invariant terms which suffice to regularize the Noether charges and render the variational problem well-posed. This is an idea that has been previously considered in the case of second-order theories, such as general relativity and which, as shown here, extends to higher-derivative theories. Besides black holes, we consider other solutions such as gravitational waves in AdS, for which we also find results that are in agreement. This enables us to investigate the consistency of this approach in the non-Einstein sector of the theory.

The scrutiny of black hole perturbations and its application to testing gravity theories have been a very crucial frontier in modern physics. In this paper we study the quasinormal modes (QNM) of massless scalar perturbations for various charged black holes in the Palatini-type theories of gravity. Specifically, we consider the Palatini $f(R)$ theory coupled with Born-Infeld nonlinear electrodynamics and the Eddington-inspired-Born-Infeld gravity (EiBI) coupled with Maxwell electromagnetic fields. Special attention is paid to Einstein-Born-Infeld black holes, EiBI charged black holes and Born-Infeld charged black holes within $R\pm R^2$ gravity. These charged black holes are shown to be stable and their quasi-normal frequencies, including the frequencies in the eikonal limit, are calculated by using the Wentzel-Kramers-Brillouin (WKB) method up to the 6th order. We compare the results with the Reissner-Nordström charged black hole and prove that both the changes in the gravity sector and the matter sector of the action alter the QNM spectra.

Simulations of relativistic hydrodynamics often need both high accuracy and robust shock-handling properties. The discontinuous Galerkin method combines these features—a high order of convergence in regions where the solution is smooth and shock-capturing properties for regions where it is not—with geometric flexibility and is therefore well suited to solve the partial differential equations describing astrophysical scenarios. We present here evolutions of a general-relativistic neutron star with the discontinuous Galerkin method. In these simulations, we simultaneously evolve the spacetime geometry and the matter on the same computational grid, which we conform to the spherical geometry of the problem. To verify the correctness of our implementation, we perform standard convergence and shock tests. We then show results for evolving, in three dimensions, a Kerr black hole; a neutron star in the Cowling approximation (holding the spacetime metric fixed); and, finally, a neutron star where the spacetime and matter are both dynamical. The evolutions show long-term stability, good accuracy, and an improved rate of convergence versus a comparable-resolution finite-volume method.

Upcoming photometric lensing surveys will considerably tighten constraints on the neutrino mass and the dark energy equation of state. Nevertheless it remains an open question of how to optimally extract the information and how well the matter power spectrum must be known to obtain unbiased cosmological parameter estimates. By performing a principal component analysis (PCA), we quantify the sensitivity of 3D cosmic shear and tomography with different binning strategies to different regions of the lensing kernel and matter power spectrum, and hence the background geometry and growth of structure in the Universe. We find that a large number of equally spaced tomographic bins in redshift can extract nearly all the cosmological information without the additional computational expense of 3D cosmic shear. Meanwhile a large fraction of the information comes from small poorly understood scales in the matter power spectrum, that can lead to biases on measurements of cosmological parameters. In light of this, we define and compute a cosmology-independent measure of the bias due to imperfect knowledge of the power spectrum. For a Euclid-like survey, we find that the power spectrum must be known to an accuracy of less than 1% on scales with $k\le 7h{\mathrm{Mpc}}^{-1}$. This requirement is not absolute since the bias depends on the magnitude of modeling errors, where they occur in $k\text{−}z$ space, and the correlation between them, all of which are specific to any particular model. We therefore compute the bias in several of the most likely modeling scenarios and introduce a general formalism and public code, RequiSim, to compute the expected bias from any nonlinear model.

We examine the oscillon formation in a recently proposed inflation model of the pure natural inflation, where the inflaton is an axion that couples to a strongly coupled pure Yang-Mills theory. The plateau of the inflaton potential, which is favored by recent observations, drives the fragmentation of the inflaton and can produce spatially localized oscillons. We find that the oscillons are formed for $F\lesssim \mathcal{O}(0.1)M_{\mathrm{pl}}$, with $F$ the effective decay constant of the model. We also comment on observational implications of the oscillons.

We construct an analytic model for the void-galaxy cross-correlation function that enables theoretical predictions of the dipole signal produced dominantly by the gravitational redshift within voids for the first time. By extending a theoretical formulation for the redshift-space distortion of galaxies to include the second order terms of the galaxy peculiar velocity $\mathit{v}$ and the gravitational potential, we formulate the void-galaxy cross-correlation function multipoles in the redshift space, the monopole ${\xi }_0^{(s)}$, dipole ${\xi }_1^{(s)}$, and quadrupole ${\xi }_2^{(s)}$. We find that the dipole ${\xi }_1^{(s)}$ is dominated by the gravitational redshift, which provides a unique opportunity to detect the gravitational potential of voids. Thus, for the dipole ${\xi }_1^{(s)}(s)$, the gravitational redshift is crucial. Although the higher order effect is almost negligible on the monopole ${\xi }_0^{(s)}$, it has an influence on the quadrupole ${\xi }_2^{(s)}$. The effects from the random velocity of galaxies and the definition of the void center on the dipole signal are also discussed. Our model offers a new theoretical probe for the detection of gravitational redshift with voids and further tests on cosmology and gravity.

We show that gravitational-wave signals from compact binary mergers may be better distinguished from instrumental noise transients by using Bayesian models that look for signal coherence across a detector network. This can be achieved even when the signal power is below the usual threshold for detection. This method could reject the vast majority of noise transients, and therefore increase sensitivity to weak gravitational waves. We demonstrate this using simulated signals, as well as data for GW150914 and LVT151012. Finally, we explore ways of incorporating our method into existing Advanced LIGO and Virgo searches to make them significantly more powerful.

The balloon-borne HiCal radio-frequency (RF) transmitter, in concert with the ANITA radio-frequency receiver array, is designed to measure the Antarctic surface reflectivity in the RF wavelength regime. The amplitude of surface-reflected transmissions from HiCal, registered as triggered events by ANITA, can be compared with the direct transmissions preceding them by $\mathcal{O}(10)$ microseconds, to infer the surface power reflection coefficient $\mathcal{R}$. The first HiCal mission (HiCal-1, Jan. 2015) yielded a sample of 100 such pairs, resulting in estimates of $\mathcal{R}$ at highly glancing angles (i.e., zenith angles approaching 90°), with measured reflectivity for those events which exceeded extant calculations [P. W. Gorham et al., Journal of Astronomical Instrumentation, 1740002 (2017)]. The HiCal-2 experiment, flying from December 2016–January 2017, provided an improvement by nearly 2 orders of magnitude in our event statistics, allowing a considerably more precise mapping of the reflectivity over a wider range of incidence angles. We find general agreement between the HiCal-2 reflectivity results and those obtained with the earlier HiCal-1 mission, as well as estimates from Solar reflections in the radio-frequency regime [D. Z. Besson et al., Radio Sci. 50, 1 (2015)]. In parallel, our calculations of expected reflectivity have matured; herein, we use a plane-wave expansion to estimate the reflectivity $\mathcal{R}$ from both a flat, smooth surface (and, in so doing, recover the Fresnel reflectivity equations) and also a curved surface. Multiplying our flat-smooth reflectivity by improved Earth curvature and surface roughness corrections now provides significantly better agreement between theory and the HiCal-2 measurements.

The higher-order corrections become increasingly important with experiments reaching the subpercent level of uncertainty as they look for physics beyond the standard model. Our goal is to address the full set of two-loop electroweak corrections to Møller or electron-proton scattering. It is a demanding task which requires an application of various approaches where two-loop calculations can be automatized. We choose to employ dispersive subloop insertion approach and develop two-loop integrals using two-point functions basis. In that basis, we introduce a partial tensor reduction for many-point Passarino-Veltman functions, which later could be used in computer algebra packages. In this paper, we have considered self-energy, triangle and box subloop insertions into self-energy, vertex and box topology.

The chromomagnetic dipole moment (CMDM) and chromoelectric dipole moment (CEDM) of the top quark are calculated at the one-loop level in the framework of the two-Higgs doublet model with four fermion generations (4GTHDM), which is still consistent with experimental data and apart from new scalar bosons ($H^0$, $A^0$, and $H^{\pm }$) and quarks ($b^{\prime }$ and $t^{\prime }$) predicts new sources of $CP$ violation via the extended $4\times 4$ CKM matrix. Analytical expressions for the CMDM and CEDM of a quark are presented both in terms of Feynman parameter integrals, which are explicitly integrated, and Passarino-Veltman scalar functions, with the main contributions arising from loops carrying the scalar bosons accompanied by the third- and fourth-generation quarks. The current bounds on the parameter space of the 4GTHDM are discussed and a region still consistent with the LHC data on the 125 GeV Higgs boson and the oblique parameters is identified. It is found that the top quark CMDM, which is induced by all the scalar bosons, can reach values of the order of ${10}^{-2}–{10}^{-1}$. As for the top quark CEDM, it only receives contributions from the charged scalar boson and can reach values of the order of ${10}^{-20}–{10}^{-19}\mathrm{ecm}$ for relatively light $m_{H^{\pm }}$ and heavy $m_{b^{\prime }}$, with the dominant contribution arising from the $b$ quark. The CEDM would be the most interesting prediction of this model as it can be larger than the value predicted by the usual THDMs by one order of magnitude.

In orbifold family unification on the basis of $SU(N)$ gauge theory on the six-dimensional space-time $M^4\times T^2/Z_m$ ($m=2$, 3, 4, 6), enormous numbers of models with three families of the standard model matter multiplets are derived from a massless Dirac fermion in a vectorlike representation $[N,3]+[N,N-3]$ of $SU(N)$ ($N=8$, 9). They contain models with three or more than three neutrino singlets and without any non-Abelian continuous flavor gauge symmetries. The relationship between flavor numbers from a fermion in $[N,N-k]$ and those from a fermion in $[N,k]$ are studied from the viewpoint of charge conjugation.

We demonstrate that in a class of the $U(1{)}^{\prime }$ extension of the Standard Model (SM), under which all the Standard Model matter fields are uncharged and the additional neutral gauge boson $Z^{\prime }$ couples to a set of heavy nonstandard fermions, dark matter (DM) production mediated by $Z^{\prime }$ can proceed through the generation of generalized Chern-Simons (GCS) couplings. The origin of the GCS terms is intimately connected to the cancellation of gauge anomalies. We show that the DM production cross section triggered by GCS couplings is sufficient even for an intermediate scale $Z^{\prime }$. A large range of DM and $Z^{\prime }$ masses is then allowed for reasonably high reheating temperature ($T_{\mathrm{RH}}\gtrsim {10}^{10}\mathrm{GeV}$). This type of scenario opens up a new paradigm for unified models. We also study the UV completion of such effective field theory constructions, augmenting it by a heavy fermionic spectrum. The latter, when integrated out, generates the GCS-like terms and provides a new portal to the dark sector. The presence of a number of derivative couplings in the GCS-like operators induces a high temperature dependence in the DM production rate. The mechanism has novel consequences and leads to a new reheating dependence of the relic abundance.

The well-known baryon and lepton numbers of the standard model of quarks and leptons are extended to include new fermions and bosons in a simple structure with several essential features. The usual heavy right-handed neutrino singlets (for neutrino mass and leptogenesis) are related to the axion which solves the strong $CP$ problem. At the same time, baryon number is broken softly, allowing the proton to decay. Associated with this breaking, a long-lived dark-matter candidate (called the pseudosakharon) emerges. This new insight connects proton decay to a new component of dark matter.

We propose an extension of the standard model with an extra $U(1{)}^{\prime }$ Abelian symmetry, three Higgs doublets and two Higgs singlets, where the new $U(1{)}^{\prime }$ charges are flavor nonuniversal. As a result, the model introduces an enlarger particle spectrum in the TeV scale with large new physics possibilities. The model reproduces the mixing angles and mass structures of the quarks, charged and neutral leptons. We found scenarios where the observed anomaly of the $B^{+}\to K^{+}\ell \ell$ decay can be explained due to the existence of couplings with new extra fermions at the TeV scale. By modifying the parametrization of the mixing matrices, we found solution in the decoupling limit.

We introduce a method to investigate the static and dynamic properties of both Abelian and non-Abelian lattice gauge models in $1+1$ dimensions. Specifically, we identify a set of transformations that disentangle different degrees of freedom, and apply a simple Gaussian variational ansatz to the resulting Hamiltonian. To demonstrate the suitability of the method, we analyze both static and dynamic aspects of string breaking for the U(1) and SU(2) gauge models. We benchmark our results against tensor network simulations and observe excellent agreement, although the number of variational parameters in the Gaussian ansatz is much smaller.