Scalar fields pervade theoretical physics and are a fundamental ingredient to solve the dark matter problem, to realize the Peccei-Quinn mechanism in QCD or the string-axiverse scenario. They are also a useful proxy for more complex matter interactions, such as accretion disks or matter in extreme conditions. Here, we study the collision between scalar “clouds” and rotating black holes. For the first time we are able to compare analytic estimates and strong field, nonlinear numerical calculations for this problem. As the black hole pierces through the cloud it accretes according to the Bondi-Hoyle prediction, but is deflected through a purely kinematic gravitational “anti-Magnus” effect, which we predict to be present also during the interaction of black holes with accretion disks. After the interaction is over, we find large recoil velocities in the transverse direction. The end-state of the process belongs to the vacuum Kerr family if the scalar is massless, but can be a hairy black hole when the scalar is massive.

We establish the functional renormalization group as an exploratory tool to investigate a possible phase transition between a pregeometric discrete phase and a geometric continuum phase in quantum gravity. In this paper, based on the analysis of Eichhorn and Koslowski [Phys. Rev. D 88, 0840156 (2013)], we study three new aspects of the double-scaling limit of matrix models as renormalization group fixed points. First, we investigate multicritical fixed points, which are associated with quantum gravity coupled to conformal matter. Second, we discuss an approximation that reduces the scheme dependence of our results as well as computational effort while giving good numerical results. This is a consequence of the approximation being a solution to the unitary Ward identity associated to the U(N) symmetry of the Hermitian matrix model. Third, we discuss a scenario that relates the double-scaling limit to fixed points of continuum quantum gravity.

When extracting cosmological information from power spectrum measurements, we must consider the impact of super-sample density fluctuations whose wavelengths are larger than the survey scale. These modes contribute to the mean density fluctuation ${\delta }_{\mathrm{b}}$ in the survey and change the power spectrum in the same way as a change in the cosmological background. They can be simply included in cosmological parameter estimation and forecasts by treating ${\delta }_{\mathrm{b}}$ as an additional cosmological parameter enabling efficient exploration of its impact. To test this approach, we consider here an idealized measurement of the matter power spectrum itself in the $\mathrm{\Lambda }\mathrm{CDM}$ cosmology though our techniques can readily be extended to more observationally relevant statistics or other parameter spaces. Using subvolumes of large-volume $N$-body simulations for power spectra measured with respect to either the global or local mean density, we verify that the minimum variance estimator of ${\delta }_{\mathrm{b}}$ is both unbiased and has the predicted variance. Parameter degeneracies arise since the response of the matter power spectrum to ${\delta }_{\mathrm{b}}$ and cosmological parameters share similar properties in changing the growth of structure and dilating the scale of features especially in the local case. For matter power spectrum measurements, these degeneracies can lead in certain cases to substantial error degradation and motivates future studies of specific cosmological observables such as galaxy clustering and weak lensing statistics with these techniques.

It has been recently shown that any halo velocity bias present in the initial conditions does not decay to unity, in agreement with predictions from peak theory. However, this is at odds with the standard formalism based on the coupled-fluids approximation for the coevolution of dark matter and halos. Starting from conservation laws in phase space, we discuss why the fluid momentum conservation equation for the biased tracers needs to be modified in accordance with the change advocated in Baldauf et al. Our findings indicate that a correct description of the halo properties should properly take into account peak constraints when starting from the Vlasov-Boltzmann equation.

We deform $N$-dimensional (Euclidean, spherical and hyperbolic) oscillator and Coulomb systems, replacing their angular degrees of freedom by those of a generalized rational Calogero model. Using the action-angle description, it is established that maximal superintegrability is retained. For the rational Calogero model with Coulomb potential, we present all constants of motion via matrix model reduction. In particular, we construct the analog of the Runge–Lenz vector.

The ${\gamma }^{*}N\to N^{*}(1520)$ reaction is studied in the framework of the light cone QCD sum rules method. The sum rules for the multipole form factors, namely, for the magnetic dipole $G_M(Q^2)$, electric quadrupole $G_E(Q^2)$, and Coulomb quadrupole $G_C(Q^2)$ [i.e., form factors responsible for the ${\gamma }^{*}N\to N^{*}(1520)$ transition] are derived. Using these sum rules, the helicity amplitudes are presented as combinations of these multipole form factors, and their $Q^2$ dependences are studied. We compare our results on the helicity amplitudes with those of the spectator model predictions and with the existing experimental data.

The appearance of the radion field and of the radion, the corresponding lowest Kaluza-Klein (KK) mode, is a generic prediction of stabilized brane world models. In such models the radion plays the role of the dilaton, and its mass may be somewhat smaller than that of all the KK modes of other particles propagating in the multidimensional bulk. Because of its origin, the radion couples to the trace of the energy-momentum tensor of the standard model (SM), the interaction Lagrangian of the radion, and the standard model fermions similar to those of the SM Higgs boson-fermion interactions except for additional terms, which come into play only in the case of off-shell fermions. In the present paper it is shown that all the contributions due to these additional terms to perturbative amplitudes of physical processes with emitted single radion and an arbitrary number of gauge bosons are canceled out for both massless and massive off-shell fermions. Thus, in this case the additional fermion-radion terms in the interaction Lagrangian do not alter any production and decay properties of the radion compared to those of the Higgs boson.

We suggest a criterion to minimize the amount of fine-tuning in a composite Higgs model. The paradigm of this type of model is the top-condensate model of Bardeen-Hill-Lindner. Although “minimally fine-tuned,” this model fails to account correctly for the masses of the top quark and the 125 GeV Higgs boson. We propose a generalization of the Bardeen-Hill-Lindner model that employs finely tuned extended technicolor plus technicolor (TC) interactions. The additional freedom of this model may accommodate both $m_t(173)$ and $M_H(125)$. This paper studies the large-$N_{\mathrm{TC}}$ and -$N_C$ limit of this model in which technicolor is weak and does not contribute to electroweak symmetry breaking. Refinements including walking-TC dynamics and a renormalization-group analysis of $m_t$ and $M_H$ will appear in a subsequent paper. A likely generic signal of this model is enhanced production of longitudinally polarized weak bosons, alone and in association with $H(125)$.

We present a numerical analysis of helicity independent nucleon generalized parton distributions (GPDs) using the known formalism based on inclusion of higher Fock states in the soft-wall approach of the anti–de Sitter/QCD model. We calculate the momentum space GPDs by matching the electromagnetic form factors in the AdS model to the sum rules in QCD. We investigate their Mellin moments, transverse impact parameter GPDs, transverse mean square radius, and transverse width. We further extend this work to investigate the charge and anomalous magnetization densities for both unpolarized and transversely polarized nucleons. A comparison of results on density functions with phenomenological parametrization is also presented.

We study the $W^{+}{W}^{-}$ and $Z^0{Z}^0$ electroweak boson production in double parton scattering using QCD evolution equations for double parton distributions. In particular, we analyze the impact of splitting terms in the evolution equations on the double parton scattering cross sections. Unlike the standard terms, the splitting terms are not suppressed for large values of the relative momentum of two partons in the double parton scattering. Thus, they play an important role which we discuss in detail for the single splitting contribution to the cross sections under the study.

We study interference effects in the production channel $ZZ+\text{jet}$, in particular focusing on the role of the Higgs boson. This production channel receives contributions both from Higgs boson mediated diagrams via the decay $H\to ZZ$ (signal diagrams), as well as from diagrams where the $Z$ bosons couple directly to a quark loop (background diagrams). We consider the partonic processes $gggZZ$ and $gq\overline{q}ZZ$ in which interference between signal and background diagrams first occurs. Since interference is primarily an off-resonant effect for the Higgs boson, we treat the $Z$ bosons as on shell. Thus our analysis is limited to the region above threshold, where the invariant mass of the $Z$-pair $m_{ZZ}$ satisfies the condition $m_{ZZ}>2m_Z$. In the region $m_{ZZ}>300\mathrm{GeV}$ we find that the interference in the $ZZ+\text{jet}$ channel is qualitatively similar to interference in the inclusive $ZZ$ channel. Moreover, the rates are sufficient to study these effects at the LHC once jet-binned data become available.

We use an effective field theory which includes all possible gluon-Higgs dimension-5 and dimension-7 operators to study Higgs boson plus jet production in next-to-leading order QCD. The effective field theory sheds light on the effect of a finite top quark mass as well as any beyond-the-Standard-Model modifications of Higgs-gluon effective couplings. In the gluon channel, the accuracy of the heavy-top approximation for differential distributions arises from the noninterference between the helicity amplitudes of the $G^{3}h$ and $G^{2}h$ operators in the $m_h<p_T$ limit at lowest order. One dimension-7 operator involving quark bilinears, however, contributes significantly at high $p_T$ and potentially offers a channel for seeing beyond-the-Standard-Model effects. One-loop renormalization of these operators is determined, allowing resummation of large logarithms via renormalization group running. Next-to-leading-order numerical results at the LHC are presented, which include $\mathcal{O}(1/m_t^2)$ contributions in the Standard Model limit.

The recent claim by BICEP2 of evidence for primordial gravitational waves has focused interest on the potential for early-Universe cosmology using gravitational waves. In addition to cosmic microwave background detectors, efforts are underway to carry out gravitational-wave astronomy with pulsar timing arrays, space-based detectors, and terrestrial detectors. These efforts will probe a wide range of times in the early Universe, during which backgrounds may have been produced through processes such as phase transitions or preheating. We derive a rule of thumb (not so strong as an upper limit) governing the maximum energy density of cosmological backgrounds. For most scenarios, we expect the energy density spectrum to peak at values of ${\mathrm{\Omega }}_{\mathrm{gw}}(f)\lesssim 10^{-12\pm 2}$. We discuss the applicability of this rule and the implications for gravitational-wave astronomy.

We construct the supergravity duals of marginal deformations of a (0, 2) Landau-Ginsburg theory that describes the supersymmetric lowest Landau level. These deformations preserve supersymmetry and it is proposed that they are associated with the introduction of a phase in the (0, 2) superpotential. We also consider marginal deformations of various field theories that exhibit Schrödinger symmetry and Lifshitz scaling. This includes countably infinite examples with dynamical exponent $z=2$ based on the Sasaki-Einstein spaces $Y^{p,q}$ and $L^{p,q,r}$, as well as an example with general dynamical exponent $z\ge 1$.

We study rigidly rotating strings in the background of ${\mathrm{AdS}}_3\times S^3$ with Neveu-Schwarz fluxes. We find two interesting limiting cases corresponding to the known giant magnon and the new single spike solution of strings in the above background and write down the dispersion relations among various conserved charges. We use proper regularization to find the correct relations among them. We further study the circular strings and infinite spikes on anti–de Sitter (AdS) and study their properties.

Three-dimensional (3D) loop quantum gravity with a vanishing cosmological constant can be related to the quantization of the SU(2) BF theory discretized on a lattice. At the classical level, this discrete model characterizes discrete flat geometries and its phase space is built from $T^{*}\mathrm{SU}(2)$. In a recent paper [Bonzom et al., arXiv:1402.2323], this discrete model was deformed using the Poisson-Lie group formalism and was shown to characterize discrete hyperbolic geometries while still being topological. Hence, it is a good candidate to describe the discretization of SU(2) BF theory with a (negative) cosmological constant. We proceed here to the quantization of this model. At the kinematical level, the Hilbert space is spanned by spin networks built on ${\mathcal{U}}_q(\mathfrak{su}(2))$ (with $q$ real). In particular, the quantization of the discretized Gauss constraint leads naturally to ${\mathcal{U}}_q(\mathfrak{su}(2))$ intertwiners. We also quantize the Hamiltonian constraint on a face of degree 3 and show that physical states are proportional to the quantum 6j symbol. This suggests that the Turaev-Viro amplitude with $q$ real is a solution of the quantum Hamiltonian. This model is therefore a natural candidate to describe 3D loop quantum gravity with a (negative) cosmological constant.

In many quantum gravity approaches, the cosmological constant is introduced by deforming the gauge group into a quantum group. In three dimensions, the quantization of the Chern-Simons formulation of gravity provided the first example of such a deformation. The Turaev-Viro model, which is an example of a spin-foam model, is also defined in terms of a quantum group. By extension, it is believed that in four dimensions, a quantum group structure could encode the presence of $\mathrm{\Lambda }\ne 0$. In this article, we introduce by hand the quantum group ${\mathcal{U}}_q(\mathfrak{s}u(2))$ into the loop quantum gravity (LQG) framework; that is, we deal with ${\mathcal{U}}_q(\mathfrak{s}u(2))$-spin networks. We explore some of the consequences, focusing in particular on the structure of the observables. Our fundamental tools are tensor operators for ${\mathcal{U}}_q(\mathfrak{s}u(2))$. We review their properties and give an explicit realization of the spinorial and vectorial ones. We construct the generalization of the $\mathrm{U}(N)$ formalism in this deformed case, which is given by the quantum group ${\mathcal{U}}_q(\mathfrak{u}(N))$. We are then able to build geometrical observables, such as the length, area or angle operators, etc. We show that these operators characterize a quantum discrete hyperbolic geometry in the three-dimensional LQG case. Our results confirm that a quantum group structure in LQG can be a tool to introduce a nonzero cosmological constant into the theory. Our construction is both relevant for three-dimensional Euclidian quantum gravity with a negative cosmological constant and four-dimensional Lorentzian quantum gravity with a positive cosmological constant.

Usually a dark energy as a perfect fluid is characterized by the ratio of pressure to energy density ($w=p/\rho$) and the ratio of their perturbations in its rest frame ($c_s^2=\delta p/\delta \rho$). However, a dark energy would have other characteristics beyond its equation of state and the effective speed of sound. Here the extra property is the anisotropic stress sourced by matter as a simple extension to the perfect fluid model. At the background level, this anisotropic stress is zero with respect to the cosmological principle, but not at the first-order perturbation. We tested the viability of the existence of this kind of anisotropic stress by using the currently available cosmic observations through the geometrical and dynamical measurements. Using the Markov-chain Monte Carlo method, we found that the upper bounds on the anisotropic stress which enters into the summation of the Newtonian potentials should be of the order $\mathcal{O}(10^{-3}){\mathrm{\Delta }}_m$. We did not find any strong evidence for the existence of this matter-sourced anisotropic stress, even in the $1\sigma$ region.

We present a decaying dark matter scenario where the daughter products are a single massless relativistic particle and a single, massive but possibly relativistic particle. We calculate the velocity distribution of the massive daughter particle and its associated equation of state and derive its dynamical evolution in an expanding universe. In addition, we present a model of decaying dark matter where there are many massless relativistic daughter particles together with a massive particle at rest. We place constraints on these two models using supernovae type Ia observations. We find that for a daughter relativistic fraction of 1% and higher, lifetimes of at least less than 10 Gyrs are excluded, with larger relativistic fractions constraining longer lifetimes.

We compute the cosmic microwave background (CMB) bispectrum induced by the evolution of the primordial density perturbations, including for the first time both temperature and polarization using a second-order Boltzmann code. We show that including polarization can increase the signal-to-noise by a factor 4 with respect to temperature alone. We find the expected signal-to-noise for this intrinsic bispectrum of $S/N=3.8,2.9,1.6$ and 0.5 for an ideal experiment with an angular resolution of ${\ell }_{\max }=3000$, the proposed CMB surveys PRISM and COrE, and Planck’s polarized data, respectively; the bulk of this signal comes from $E$-mode polarization and from squeezed configurations. We discuss how CMB lensing is expected to reduce these estimates as it suppresses the bispectrum for squeezed configurations and contributes to the noise in the estimator. We find that the presence of the intrinsic bispectrum will bias a measurement of primordial non-Gaussianity of local type by $f_{\mathrm{NL}}^{\text{intr}}=0.66$ for an ideal experiment with ${\ell }_{\max }=3000$. Finally, we verify the robustness of our results by recovering the analytic approximation for the squeezed-limit bispectrum in the general polarized case.