Quantum information transfer necessary to reconcile black hole evaporation with quantum mechanics, while approximately preserving regular near-horizon geometry, can be simply parametrized in terms of couplings of the black hole internal state to quantum fields of the black hole atmosphere. The necessity of transferring sufficient information for unitarization sets the strengths of these couplings. Such couplings via the stress tensor offer apparently significant advantages, and behave like quantum fluctuations of the effective metric near the horizon. At the requisite strength, these fluctuations, while soft (low energy/momentum), have significant magnitude, and so can deflect near-horizon geodesics that span distances of order the black hole radius. Thus, the presence of such couplings can result in effects that could be detected or constrained by observation: disruption of near-horizon accretion flows, scintillation of light passing close to the black hole, and alteration of gravitational wave emission from inspirals. These effects could in particular distort features of Sgr A* expected to be observed, e.g., by the Event Horizon Telescope, such as the black hole shadow and photon ring.

While black hole perturbation theory predicts a rich quasinormal mode structure, technical challenges have limited the numerical study of excitations to the fundamental, lowest order modes caused by the coalescence of black holes. Here, we present a robust method to identify quasinormal mode excitations beyond the fundamentals within currently available numerical relativity waveforms. In applying this method to waveforms of 68 initially nonspinning black hole binaries, of mass ratios $1:1$ to $15:1$, we find not only the fundamental quasinormal mode amplitudes, but also overtones, and evidence for second order quasinormal modes. We find that the mass-ratio dependence of quasinormal mode excitation is very well modeled by a post-Newtonian-like sum in symmetric mass ratio. Concurrently, we find that the mass-ratio dependence of some quasinormal mode excitations is qualitatively different from their post-Newtonian inspired counterparts, suggesting that the imprints of nonlinear merger are more evident in some modes than in others. We present new fitting formulas for the related quasinormal mode excitations, as well as for remnant black hole spin and mass. We also discuss the relevance of our results in terms of gravitational wave detection and characterization.

The recent classical nonlocal generalization of Einstein’s theory of gravitation is presented within the framework of general relativity via the introduction of a preferred frame field. The nonlocal generalization of Einstein’s field equations is derived. The linear approximation of nonlocal gravity is thoroughly examined and the solutions of the corresponding field equations are discussed. It is shown that nonlocality, with a characteristic length scale of order 1 kpc, simulates dark matter in the linear regime while preserving causality. Light deflection in linearized nonlocal gravity is studied in connection with gravitational lensing; in particular, the propagation of light in the weak gravitational field of a uniformly moving source is investigated. The astrophysical implications of the results are briefly mentioned.

In the quasistatic regime, generic modifications to gravity can give rise to novel scale dependence of the gravitational field equations. Crucially, the detectability of the new scale-dependent terms hinges upon the existence of an effective mass scale or length scale at which corrections to general relativity become relevant. Starting from only a few basic principles, we derive the general form of this scale dependence. Our method recovers results previously known in the specific case of Horndeski gravity, but also shows that they are valid more generally, beyond the regime of scalar field theories. We forecast the constraints that upcoming experiments will place on the existence of a new fundamental mass scale or length scale in cosmology.

The CMS collaboration has recently reported a $2.8\sigma$ excess of $eejj$ events with an invariant mass around 2 TeV. This observation can be explained in the context of standard model extensions with new gauge bosons $W^{\prime }$, $Z^{\prime }$ and heavy neutrinos coupling (mainly) to the electron. We discuss additional signals that allow us to confirm or discard the $W^{\prime }$ and $Z^{\prime }$ hypotheses.

We exploit the complementarity among supersymmetry, inflation, axions, big bang nucleosynthesis (BBN), and cosmic microwave background radiation (CMB) to constrain supersymmetric axion models in the light of the recent Planck and BICEP results. In particular, we derive BBN bounds coming from altering the light element abundances by taking into account hadronic and electromagnetic energy injection, and CMB constraints from black-body spectrum distortion. Last, we outline the viable versus excluded region of these supersymmetric models that might account for the mild dark radiation observed.

Single production of vectorlike top partners is becoming a major focus of new searches, as the increasing mass limits on vectorlike quarks obtained by the ATLAS and CMS collaborations are such that single production is becoming competitive with respect to pair production. Typically searches focus on decays containing leptons in the final state in order to have less background from the Standard Model processes. However the current centre of mass energies available in the latest LHC runs limit the searches to low masses. Fully hadronic final states may be an alternative option for discovery, as they allow a larger number of signal events if backgrounds can be kept under control. We study the fully hadronic decay of a singly produced vectorlike top partner and we show a strategy to extract the signal over the background, considering as a benchmark the $20{\mathrm{fb}}^{-1}$ of data collected at 8 TeV with the run I of the LHC.

This paper presents basic aspects of a program to put field theories quantized in radial coordinates on the lattice. It discusses only scalar fields and uses simple examples to illustrate the strategy when applied to the three-dimensional Ising model.

The Bakamjian-Thomas relativistic quark model for hadron current matrix elements, while noncovariant at finite mass, is successful in the heavy quark limit: form factors are covariant and satisfy Isgur-Wise scaling and Bjorken-Uraltsev sum rules. Motivated by the so-called “$1/2$ vs $3/2$ puzzle” in $\overline{B}$ decays to positive parity $D^{**}$, we examine the implications of the model at finite mass. In the elastic case ${\frac{1}{2}}^{-}\to {\frac{1}{2}}^{-}$, the heavy quark effective theory (HQET) constraints for the $O(1/m_Q)$ corrections are analytically fulfilled. A number of satisfying regularities is also found for inelastic transitions. We compute the form factors using the wave functions given by the Godfrey-Isgur potential. We find a strong enhancement in the case ${\frac{1}{2}}^{-}\to {\frac{1}{2}}^{+}$ for $0^{-}\to 0^{+}$. This enhancement is linked to a serious difficulty of the model at finite mass for the inelastic transitions, namely a violation of the HQET constraints at zero recoil formulated by Leibovich et al. These are nevertheless satisfied in the nonrelativistic limit for the light quark. We conclude that these HQET rigorous constraints are crucial in the construction of a sensible relativistic quark model of inelastic form factors.

Current experimental data on the 125 GeV Higgs boson still allow room for large $CP$ violation. The observables usually considered in this context are triple product asymmetries, which require an input of four visible particles after imposing momentum conservation. We point out a new class of $CP$-violating observables in Higgs physics which require only three reconstructed momenta. They may arise if the process involves an interference of amplitudes with different intermediate particles, which provide distinct “strong phases” in the form of the Breit-Wigner widths, in addition to possible “weak phases” that arise from $CP$-violating couplings of the Higgs in the Lagrangian. As an example, we propose a forward-backward asymmetry of the charged lepton in the three-body Higgs decay, $h\to {\ell }^{-}{\ell }^{+}\gamma$, as a probe for $CP$-violating Higgs couplings to $Z\gamma$ and $\gamma \gamma$ pairs. Other processes exhibiting this type of $CP$ violation are also discussed.

We derive the Euclidean time formulation for the equilibrium canonical ensemble of the type IIA and type IIB superstrings, and the $\text{spin}(32)/{\mathrm{Z}}_2$ heterotic string. We compactify on $R^8\times T^2$, and twist by the Neveu-Schwarz sector antisymmetric 2-form $B$-field potential, spontaneously breaking supersymmetry at low temperatures, while preserving the tachyon-free low-energy gravitational field theory limit. We verify that the super partners of the massless dilaton-graviton multiplet obtain a mass which is linear in the temperature. In addition, we show that the free energy for the superstring canonical ensemble at weak coupling is always strongly convergent in the ultraviolet, high-temperature, regime dominated by the highest mass level number states. We derive the precise form of the exponential suppression as a linear power of the mass level, which erases the exponential Hagedorn growth of the degeneracies as the square root of mass level number. Finally, we close a gap in previous research giving an unambiguous derivation of the normalization of the one-loop vacuum energy density of the $\text{spin}(32)/Z_2$ perturbative heterotic string theory. Invoking the O(32) type IB-heterotic strong-weak duality, we match the normalization of the one loop vacuum energy densities of the $T$-dual O(32) type IA open and closed string with that of the $\text{spin}(32)/Z_2$ heterotic string on $R^9\times S^1$, for values of the compactification radius, $R_{[\mathrm{O}(32)]}$, $R_{\mathrm{IB}}\gg {\alpha }^{\prime 1/2}$, with $R_{\mathrm{IA}}<{\alpha }^{\prime 1/2}$. We show that the type IA thermal solitonic winding spectrum is a simple model for finite temperature pure QCD, transitioning above the critical duality phase transformation temperature to the deconfined ensemble of thermally excited IB gluons.

We investigate the effect of supersymmetry preserving mass deformation near the UV fixed point represented by the $\mathcal{N}=6$ Aharony-Bergman-Jafferis-Maldacena theory. In the context of the gauge/gravity duality, we analytically calculate the leading small mass effect on the renormalized entanglement entropy (REE) for the most general Lin-Lunin-Maldacena (LLM) geometries in the cases of the strip and disk-shaped entangling surfaces. Our result shows that the properties of the REE in ($2+1$) dimensions are consistent with those of the $c$ function in ($1+1$) dimensions. We also discuss the validity of our computations in terms of the curvature behavior of the LLM geometry in the large $N$ limit and the relation between the correlation length and the mass parameter for a special LLM solution.

The detection and characterization of gravitational wave signals from compact binary coalescence events relies on accurate waveform templates in the frequency domain. The stationary phase approximation (SPA) can be used to compute closed-form frequency-domain waveforms for nonprecessing, quasicircular binary inspirals. However, until now, no fast frequency-domain waveforms have existed for generic, spin-precessing quasicircular compact binary inspirals. Templates for these systems have had to be computed via a discrete Fourier transform of finely sampled time-domain waveforms, which is far more computationally expensive than those constructed directly in the frequency domain, especially for those systems that are dominated by the inspiral part. There are two obstacles to deriving frequency-domain waveforms for precessing systems: (i) the spin-precession equations do not admit closed-form solutions for generic systems; (ii) the SPA fails catastrophically, i.e. in some situations, the second derivative of the signal phase vanishes, so that the direct application of the SPA predicts a divergent amplitude. Presently there is no general solution to the first problem, so we must resort to numerical integration of the spin-orbit precession equations. This is not a significant obstacle, as numerical integration on the slow precession time scale adds very little to the computational cost of generating the waveforms. Our main result is to solve the second problem, by providing an alternative to the SPA that we call the method of shifted uniform asymptotics (SUA) that cures the divergences in the SPA. The construction of frequency-domain templates using the SUA can be orders of magnitude more efficient than the time-domain ones obtained through a discrete Fourier transform. Moreover, this method is very faithful to the discrete Fourier transform, with mismatches on the order of $10^{-5}$.

Motivated by the equivalence between the soft graviton theorem and Ward identities for the supertranslation symmetries belonging to the Bondi, van der Burg, Metzner and Sachs (BMS) group, we propose a new extension (different from the so-called extended BMS) of the BMS group that is a semidirect product of supertranslations and $\text{Diff}(S^2)$. We propose a definition for the canonical generators associated with the smooth diffeomorphisms and show that the resulting Ward identities are equivalent to the subleading soft graviton theorem of Cachazo and Strominger.

We present an implementation of the Galerkin-Collocation method to determine the initial data for nonrotating distorted three-dimensional black holes in the inversion and puncture schemes. The numerical method combines the key features of the Galerkin and Collocation methods which produces accurate initial data. We evaluated the ADM mass of the initial data sets, and we have provided the angular structure of the gravitational wave distribution at the initial hypersurface by evaluating the scalar ${\mathrm{\Psi }}_4$ for asymptotic observers.

We present a new multivariate regression model for analysis and parameter estimation of gravitational waves observed from well but not perfectly modeled sources such as core-collapse supernovae. Our approach is based on a principal component decomposition of simulated waveform catalogs. Instead of reconstructing waveforms by direct linear combination of physically meaningless principal components, we solve via least squares for the relationship that encodes the connection between chosen physical parameters and the principal component basis. Although our approach is linear, the waveforms’ parameter dependence may be nonlinear. For the case of gravitational waves from rotating core collapse, we show, using statistical hypothesis testing, that our method is capable of identifying the most important physical parameters that govern waveform morphology in the presence of simulated detector noise. We also demonstrate our method’s ability to predict waveforms from a principal component basis given a set of physical progenitor parameters.

We consider static spherically symmetric solutions in the scalar-tensor theory of gravity with a scalar field possessing the nonminimal kinetic coupling to the curvature. The Lagrangian of the theory contains the term $(ϵg^{\mu \nu }+\eta G^{\mu \nu }){\varphi }_{,\mu }{\varphi }_{,\nu }$ and represents a particular case of the general Horndeski Lagrangian, which leads to second-order equations of motion. We use the Rinaldi approach to construct analytical solutions describing wormholes with nonminimal kinetic coupling. It is shown that wormholes exist only if $ϵ=-1$ (phantom case) and $\eta >0$. The wormhole throat connects two anti–de Sitter spacetimes. The wormhole metric has a coordinate singularity at the throat. However, since all curvature invariants are regular, there is no curvature singularity there.

We consider a scalar-tensor model of dark energy with Gauss-Bonnet and nonminimal couplings. Exact cosmological solutions were found in the absence of potential that give equations of state of dark energy consistent with current observational constraints, but with different asymptotic behaviors depending on the couplings of the model. A detailed reconstruction procedure is given for the scalar potential and the Gauss-Bonnet coupling for any given cosmological scenario. In particular we consider conditions for the existence of a variety of cosmological solutions with accelerated expansion, including quintessence, phantom, de Sitter, and Little Rip. For the case of quintessence and phantom we have found a scalar potential of the Albrecht-Skordis type, where the potential is an exponential with a polynomial factor.

Directional detection of weakly interacting massive particles, in which the energies and directions of the recoiling nuclei are measured, currently presents the only prospect for probing the local velocity distribution of Galactic dark matter. We investigate the extent to which future directional detectors would be capable of probing dark matter substructure in the form of streams. We analyze the signal expected from a Sagittarius-like stream and also explore the full parameter space of stream speed, direction, dispersion and density. Using a combination of nonparametric directional statistics, a profile likelihood ratio test and Bayesian parameter inference we find that within acceptable exposure times [$\mathcal{O}(10)\mathrm{kg}\mathrm{yr}$ for cross sections just below the current exclusion limits] future directional detectors will be sensitive to a wide range of stream velocities and densities. We also examine and discuss the importance of the energy window of the detector.

The High Altitude Water Cherenkov (HAWC) observatory is a wide field-of-view detector sensitive to gamma rays of 100 GeV to a few hundred TeV. Located in central Mexico at 19° North latitude and 4100 m above sea level, HAWC will observe gamma rays and cosmic rays with an array of water Cherenkov detectors. The full HAWC array is scheduled to be operational in Spring 2015. In this paper, we study the HAWC sensitivity to the gamma-ray signatures of high-mass (multi-TeV) dark matter annihilation. The HAWC observatory will be sensitive to diverse searches for dark matter annihilation, including annihilation from extended dark matter sources, the diffuse gamma-ray emission from dark matter annihilation, and gamma-ray emission from nonluminous dark matter subhalos. Here we consider the HAWC sensitivity to a subset of these sources, including dwarf galaxies, the M31 galaxy, the Virgo cluster, and the Galactic center. We simulate the HAWC response to gamma rays from these sources in several well-motivated dark matter annihilation channels. If no gamma-ray excess is observed, we show the limits HAWC can place on the dark matter cross section from these sources. In particular, in the case of dark matter annihilation into gauge bosons, HAWC will be able to detect a narrow range of dark matter masses to cross sections below thermal. HAWC should also be sensitive to nonthermal cross sections for masses up to nearly 1000 TeV. The constraints placed by HAWC on the dark matter cross section from known sources should be competitive with current limits in the mass range where HAWC has similar sensitivity. HAWC can additionally explore higher dark matter masses than are currently constrained.