118466324
Nonlinear CMB temperature anisotropy from gravitational perturbations
Nonlinear CMB temperature anisotropies up to the third order on large scales are calculated. On large scales and in the Sachs-Wolfe limit, we give the explicit expression for the observed temperature anisotropy in terms of the primordial curvature perturbation up to the third order. We derived the final bispectrum and trispectrum of anisotropies and the corresponding nonlinear parameters, in which the contributions to the observed non-Gaussianity from primordial perturbations and from the nonlinear mapping from primordial curvature perturbation to the temperature anisotropy are transparently separated.
119252720
From k-essence to generalised Galileons
We determine the most general scalar field theories which have an action that depends on derivatives of order two or less, and have equations of motion that stay second order and lower on flat space-time. We show that those theories can all be obtained from linear combinations of Lagrangians made by multiplying a particular form of the Galileon Lagrangian by an arbitrary scalar function of the scalar field and its first derivatives. We also obtain curved space-time extensions of those theories which have second-order field equations for both the metric and the scalar field. This provides the most general extension, under the condition that field equations stay second order, of k-essence, Galileons, k-Mouflage as well as of the kinetically braided scalars. It also gives the most general action for a possible scalar classicalizer with second-order field equations. We discuss the relation between our construction and the Euler hierarchies of Fairlie et al. showing, in particular, that Euler hierarchies allow one to obtain the most general theory when the latter is shift symmetric. As a simple application of our formalism, we give the covariantized version of the conformal Galileon.
118951601
Derivative interactions for a spin-2 field at cubic order
Lorentz invariant derivative interactions for a single spin-2 field are investigated, up to the cubic order. We start from the most general Lorentz invariant terms involving two spacetime derivatives, which are polynomials in the spin-2 field as well as its first derivatives. Using a perturbative Arnowitt-Deser-Misner analysis, we determined the parameters such that the corresponding Hamiltonian possesses a Lagrange multiplier, which would signify there are at most 5 degrees of freedom that are propagating. The resulting derivative terms are linear combinations of terms coming from the expansion of the Einstein-Hilbert Lagrangian around a Minkowski background, as well as the cubic "pseudolinear derivative term" identified in Hinterbichler [J. High Energy Phys. 10 (\textbf{2013}) 102]. We also derived the compatible potential terms, which are linear combinations of the expansions of the first two de Rham-Gabadadze-Tolley mass terms in unitary gauge.
118591690
On the primordial trispectrum from exchanging scalar modes in general multiple field inflationary models
We make a complementary investigation of the primordial trispectrum from exchanging intermediate scalar modes in multi-field inflationary models with generalized kinetic terms. Together with the calculation of irreducible contributions to the primordial trispectrum in ref. [104], we give the full leading-order primordial trispectrum in generalized multi-field models.
1159729
Loop corrections to cosmological perturbations in multi-field inflationary models
We investigate one-loop quantum corrections to the power spectrum of adiabatic perturbation from entropy modes/adiabatic mode cross-interactions in multiple DBI inflationary models. We find that due to the non-canonical kinetic term in DBI models, the loop corrections are enhanced by slow-varying parameter epsilon and small sound speed c(s). Thus, in general the loop-corrections in multi-DBI models can be large. Moreover, we find that the loop-corrections from adiabatic/entropy cross-interaction vertices are IR finite.
119111716
Inflation and primordial non-Gaussianities of “generalized Galileons”
We set up cosmological perturbation theory and study the cosmological implications of the so-called "generalized Galileon" developed in [6, 7]. This is the most general scalar field theory whose Lagrangian contains derivatives up to second order while keeping second order equations of motion, and contains as sub-cases k-inflation, G-inflation and many other models. We calculate the power spectrum of the primordial curvature perturbation, finding a modification of the usual consistency relation of the tensor-to-scalar ratio in k-inflation or perfect fluid models. Finally we also calculate the bispectrum, which contains no new shapes beyond those of k-inflation.
119114774
On non-Gaussianities in two-field poly-instanton inflation
A bstractIn the context of Type IIB LARGE volume orientifold setup equipped with poly-instanton corrections, the standard single-field poly-instanton inflation driven by a ‘Wilson’ divisor volume modulus is generalized by the inclusion of respective axion modulus. This two-field dynamics results in a “Roulette” type inflation with the presence of several inflationary trajectories which could produce 50 (or more) e-foldings. The evolution of various trajectories along with physical observables are studied. The possibility of generating primordial non-Gaussianities in the slow-roll as well as in the beyond slow-roll region is investigated. We find that although the non-linearity parameters are quite small during the slow-roll regime, the same are significantly enhanced in the beyond slow-roll regime investigated up to the end of inflation.
119282531
Non-equilibrium field dynamics of an honest holographic superconductor
A bstractMost holographic models of superconducting systems neglect the effects of dynamical boundary gauge fields during the process of spontaneous symmetry-breaking. Usually a global symmetry gets broken. This yields a superfluid, which then is gauged “weakly” afterwards. In this work we build and probe the dynamics of a holographic model in which a local boundary symmetry is spontaneously broken instead. We compute two-point functions of dynamical non-Abelian gauge fields in the normal and in the broken phase, and find non-trivial gapless modes. Our AdS3 gravity dual realizes a p-wave superconductor in (1+1) dimensions. The ground state of this model also breaks (1 + 1) dimensional parity spontaneously, while the Hamiltonian is parity-invariant. We discuss possible implications of our results for a wider class of holographic liquids.
119246227
Cosmological observables in multi-field inflation with a non-flat field space
Using delta N formalism in the context of a generic multi-field inflation driven on a non-flat field space background, we revisit the analytic expressions of the various cosmological observables such as scalar tensor power spectra, scalar/tensor spectral tilts, non-Gaussianity parameters, tensor-to-scalar ratio, and the various runnings of these observables. In our backward formalism approach, the subsequent expressions of observables automatically include the terms beyond the leading order slow-roll expansion correcting many of the expression at subleading order. To connect our analysis properly with the earlier results, we rederive the (well) known (single field) expressions in the limiting cases of our generic formulae. Further, in the light of PLANCK results, we examine for the compatibility of the consistency relations within the slow-roll regime of a two-field roulette poly-instanton inflation realized in the context, of large volume scenarios.
41586733
Combining universal and odd RR axions for aligned natural inflation
We successfully embed the Kim-Nilles-Peloso (KNP) alignment mechanism for enhancing the axion decay constant in the context of large volume type IIB orientifolds. The flat direction is generated in the plane of (C-0-C-2) axions corresponding to the involutively even universal axion C-0 and odd axion C-2, respectively. The moduli stabilization with large volume scheme has been established as well.
119211261
Dimensional oxidation of non-geometric fluxes in type II orientifolds
A bstractSome aspects of string compactifications with non-geometric fluxes are revisited in the light of recent progress in double field theory. After rederiving the general form of these fluxes, we consider the proposed flux induced four-dimensional effective superpotential and oxidize its induced scalar potential to terms in a ten-dimensional action. This analysis is performed independently for an explicit toroidal type IIA and its T-dual type IIB orientifold. We show in detail that the result of this bottom-up approach is compatible with the gauged supergravity motivated flux formulation of the double field theory action in both the NS-NS and the R-R sector.