In arXiv:hep-th/0011245, in the context of domain wall backgrounds, it was shown that spontaneous breaking of diffeomorphism invariance results in gravitational Higgs mechanism. Recently in arXiv:0708.3184 't Hooft discussed gravitational Higgs mechanism in the context of obtaining massive gravity directly in four dimensions, and pointed out some subtleties with unitarity. We attribute these subtleties to breaking time-like diffeomorphisms, and discuss gravitational Higgs mechanism with all but time-like diffeomorphisms spontaneously broken. The resulting background is no longer flat but exhibits expansion, which is linear in time. For space-time dimensions D <= 10 the background is stable and has no non-unitary propagating modes. The absence of non-unitary modes is due to the unbroken time-like diffeomorphism invariance. The physical states correspond to those of a massive graviton. The effective mass squared of the graviton is positive for D < 10, and vanishes for D = 10. For D > 10 the graviton modes become effectively tachyonic. The special value of D=10, which coincides with the critical dimension of superstring theory, arises in our setup completely classically.
Starobinsky inflation and Higgs inflation in gravity, and their equivalence based on the common inflationary potential are extended to supergravity in the proper framework, where the Starobinsky and Higgs descriptions of inflation arise in two different gauges of the same supergravity model.
Models of inflation in which the Higgs field is non-minimally coupled to gravity lead, after a recaling of the metric, to a complicated expression for the potential of the inflaton field. Nevertheless, this potential produces the desired features, both theoretical and experimental, after some approximations are made. In this note, we also allow for a modification of the Higgs kinetic term in such a way that the resulting potential for the inflaton field is, without any approximation, of the simplest form after the rescaling of the metric.
This article investigates the effects of Tree Level Higgs Potential on reheating in $f(Q)$ gravity. We examine the formalism of tree level inflation in a modified $f(Q)$ model, finding that the slow roll and e-folds number during inflation depend on the $f(Q)$ model $α$ parameter. Additionally, we calculate the reheating as a function of the decay rate, constraining the inflationary parameters and reheating temperature. Our study reveals that the Tree Level Higgs Potential influences the reheating temperature and decay rate. We conclude that increasing the decay rate energy leads to higher reh…
We derive a Higgs inflationary model in the context of a complex geometrical scalar-tensor theory of gravity. In this model the Higgs inflaton scalar field has geometrical origin playing the role of the Weyl scalar field in the original non-riemannian background geometry. The energy scale enough to generate inflation from the Higgs energy scale is achieved due to the compatibility of the theory with its background complex Weyl-integrable geometry. We found that for a number of e-foldings $N=63$, a nearly scale invariant spectrum for the inflaton is obtained with an spectral index $n_s\simeq 0.…
We consider an extension of Higgs inflation in which the Higgs field is non-minimally coupled to gravity through its kinetic term. We analyzed power-law coupling functions with positive or negative integer power and found that the Higgs boson can drive a successful inflation only for the cases $n=2,1,0,-1$. Theoretical predictions for both tensor to scalar ratio $r$ and scalar spectral index $n_s$ are within the 2018 \textit{Planck} $95\%$ CL. The behavior of the self coupling $λ$ with respect to the scalar field at the horizon crossing was obtained, and It was found that it can take values in…
First, we propose a scale-invariant modified gravity interacting with a neutral scalar "inflaton" and a Higgs-like SU(2)xU(1) iso-doublet scalar field based on the formalism of non-Riemannian (metric-independent) spacetime volume-elements. This model describes in the physical Einstein frame a quintessential inflationary scenario driven by the "inflaton" together with gravity-inflaton assisted dynamical spontaneous SU(2)xU(1) symmetry breaking in the post-inflationary universe, whereas SU(2)xU(1) symmetry remains intact in the inflationary epoch. Next, we find the explicit representation of the…
We consider a family of new Higgs-Chern-Simons (HCS) gravity models in 2n+1 dimensions (n=1,2,3). This provides a generalization of the (usual) gravitational Chern-Simons (CS) gravitaties resulting from non- Abelian CS densities in all odd dimensions, which feature vector and scalar fields in addition to the metric. The derivation of the new HCS gravitational (HCSG) actions follows the same method as in the usual-CSG case resulting from the usual CS densities. The HCSG result from the HCS densities, which result through a one-step descent of the Higgs-Chern-Pontryagin (HCP), the latter being d…
In this letter we investigate gauge invariant scalar fluctuations of the metric in a non-perturbative formalism for a Higgs inflationary model recently introduced in the framework of a geometrical scalar-tensor theory of gravity. In this scenario the Higgs inflaton field has its origin in the Weyl scalar field of the background geometry. We found a nearly scale invariance of the power spectrum for linear scalar fluctuations of the metric. For certain parameters of the model we obtain values for the scalar spectral index $n_s$ and the scalar to tensor ratio $r$ that fit well with the Planck 201…
Higgs Mechanism for New Massive Gravity and Weyl Invariant Extensions of Higher Derivative Theories
New Massive Gravity为2+1维的引力子提供了Fierz-Pauli质量的非线性扩展。在这里，我们构建一个外尔不变的版本，这个理论。当外尔对称性破缺时，引力子会得到类似于希格斯机制的质量。在（反）-de Sitter背景中，对称性可以自发破缺，而在平坦背景中，辐射修正在双圈水平上，以Coleman-Weinberg机制破缺Weyl对称性。我们还构造了其他一些高阶导数模型的Weyl不变扩张，如Gauss-Bonnet理论（在三维中约化为Maxwell理论）和Born-Infeld型引力。
We present an updated review of Kraichnan's derivation of Einstein's equations from quantum field theory, including the period after the discovery of the Higgs mechanism. Gravitation in the Einstein sense is seen to be renormalizable and consistent with the Standard Model of Fundamental Interactions.
There are indications that an asymptotically safe UV completion of the Standard Model with gravity could constrain the Higgs self-coupling, resulting in a prediction of the Higgs mass close to the vacuum stability bound in the Standard Model. The predicted value depends on the top quark mass and comes out somewhat higher than the experimental value if the current central value for the top quark mass is assumed. Beyond the Standard Model, the predicted value also depends on dark fields coupled through a Higgs portal. Here we study the Higgs self-coupling in a toy model of the Standard Model wit…
We consider Weyl's conformal gravity coupled to a complex matter field in Weyl geometry. It is shown that a Higgs potential naturally arises from a $\tilde R^2$ term in moving from the Jordan frame to the Einstein frame. A massless Nambu-Goldstone boson, which stems from spontaneous symmetry breakdown of the Weyl gauge invariance, is absorbed into the Weyl gauge field, thereby the gauge field becoming massive. We present a model where the gravitational interaction generates a Higgs potential whose form is a perfect square. Finally, we show that a theory in the Jordan frame is gauge-equivalent …
059<p type="texpara" tag="Body Text" et="f_0" bin="clone" >Massive Gauge Field Theory Without Higgs Mechanism Massive Gauge Field Theory Without Higgs Mechanism III. Proof of Renormalizability
We study the parametrization and gauge dependences in the Higgs field coupled to gravity in the context of asymptotic safety. We use the exponential parametrization to derive the fixed points for the cosmological constant, Planck mass, Higgs mass and its coupling, keeping arbitrary gauge parameters $α$ and $β$, and compare the results with the linear split. We find that the beta functions for the Higgs potential are expressed in terms of redefined Planck mass such that the apparent gauge dependence is absent. Only the trace mode of the gravity fluctuations couples to the Higgs potential and it…
