Dražen Glavan
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View article: One-loop correction to primordial tensor modes during radiation era
One-loop correction to primordial tensor modes during radiation era Open
A bstract The ability to infer properties of primordial inflation relies on the conservation of the superhorizon perturbations between their exit during inflation, and their re-entry during radiation era. Any considerable departure from th…
Spectrum of pure $R^2$ gravity: full Hamiltonian analysis Open
We perform a full Hamiltonian constraint analysis of pure Ricci-scalar-squared ($R^2$) gravity to clarify recent controversies regarding its particle spectrum. While it is well established that the full theory consistently propagates three…
Measurements in stochastic gravity and thermal variance Open
We analyze the thermal fluctuations of a free, conformally invariant, Maxwell quantum field (photon) interacting with a cosmological background spacetime, in the framework of quantum field theory in curved spacetimes and semiclassical and …
Two simple photon gauges in inflation Open
A bstract Photon propagators for power-law inflation are constructed in two one-parameter families of noncovariant gauges, in an arbitrary number of spacetime dimensions. In both gauges photon propagators take relatively simple forms expre…
View article: One-loop correction to primordial tensor modes during radiation era
One-loop correction to primordial tensor modes during radiation era Open
The ability to infer properties of primordial inflation relies on the conservation of the superhorizon perturbations between their exit during inflation, and their re-entry during radiation era. Any considerable departure from this propert…
Removing spurious degrees of freedom from EFT of gravity Open
In the effective field theory approach to gravity, the Lagrangian density for general relativity is supplemented by generally covariant terms of higher order in the Riemann tensor and its derivatives. At face value, these terms will result…
Critical reassessment of the restricted Weyl symmetry Open
A class of globally scale-invariant scalar-tensor theories have been proposed to be invariant under a larger class of transformations that take the form of local Weyl transformations supplemented by a restriction that the conformal factor …
Removing spurious degrees of freedom from EFT of gravity Open
In the effective field theory approach to gravity, the Lagrangian density for general relativity is supplemented by generally covariant terms of higher order in the Riemann tensor and its derivatives. At face value, these terms will result…
Photon quantization in cosmological spaces Open
Canonical quantization of the photon—a free massless vector field—is considered in cosmological spacetimes in a two-parameter family of linear gauges that treat all the vector potential components on equal footing. The goal is setting up a…
Hamiltonian analysis of metric-affine-R <sup>2</sup> theory Open
Determining the number of propagating degrees of freedom in metric-affine theories of gravity requires the use of Hamiltonian constraint analysis, except in some subclasses of theories. We develop the technicalities necessary for such anal…
Gauge independent logarithms from inflationary gravitons Open
A bstract Dependence on the graviton gauge enters the conventional effective field equations because they fail to account for quantum gravitational correlations with the source which excites the effective field and with the observer who me…
Hamiltonian analysis of metric-affine-$R^2$ theory Open
Determining the number of propagating degrees of freedom in metric-affine theories of gravity requires the use of Hamiltonian constraint analysis, except in some subclasses of theories. We develop the technicalities necessary for such anal…
When tadpoles matter: one-loop corrections for spectator Higgs in inflation Open
A bstract We consider the classical attractor regime of the spectator Abelian Higgs model in power-law inflation, and compute the one-loop corrections to its evolution. For computations we utilize dimensional regularization and the propaga…
Explaining large electromagnetic logarithms from loops of inflationary gravitons Open
A bstract Recent progress on nonlinear sigma models on de Sitter background has permitted the resummation of large inflationary logarithms by combining a variant of Starobinsky’s stochastic formalism with a variant of the renormalization g…
Explaining Large Electromagnetic Logarithms from Loops of Inflationary Gravitons Open
Recent progress on nonlinear sigma models on de Sitter background has permitted the resummation of large inflationary logarithms by combining a variant of Starobinsky's stochastic formalism with a variant of the renormalization group. We r…
When tadpoles matter: One-loop corrections for spectator Higgs in inflation Open
We consider the classical attractor regime of the spectator Abelian Higgs model in power-law inflation, and compute the one-loop corrections to its evolution. For computations we utilize dimensional regularization and the propagators in th…
Photon propagator in de Sitter space in the general covariant gauge Open
A bstract We consider a free photon field in D -dimensional de Sitter space, and construct its propagator in the general covariant gauge. Canonical quantization is employed to define the system starting from the classical theory. This guar…
Photon quantization in cosmological spaces Open
Canonical quantization of the photon -- a free massless vector field -- is considered in cosmological spacetimes in a two-parameter family of linear gauges that treat all the vector potential components on equal footing. The goal is settin…
Even the photon propagator must break de Sitter symmetry Open
The propagator for the massless vector field in de Sitter space cannot maintain de Sitter invariance in the general covaraint gauge, except in the exactly transverse gauge limit. This is due to a previously overlooked Ward-Takahashi identi…
Photon propagator in de Sitter space in the general covariant gauge Open
We consider a free photon field in $D$-dimensional de Sitter space, and construct its propagator in the general covariant gauge. Canonical quantization is employed to define the system starting from the classical theory. This guarantees th…
Large logarithms from quantum gravitational corrections to a massless, minimally coupled scalar on de Sitter Open
A bstract We consider single graviton loop corrections to the effective field equation of a massless, minimally coupled scalar on de Sitter background in the simplest gauge. We find a large temporal logarithm in the approach to freeze-in a…
One-loop graviton corrections to conformal scalars on a de Sitter background Open
We exploit a recent computation of one graviton loop corrections to the self-mass [D. Glavan et al., Single graviton loop contribution to the self-mass of a massless, conformally coupled scalar on a de Sitter background, Phys. Rev. D 101, …
One-loop Graviton Corrections to Conformal Scalars on de Sitter Open
We exploit a recent computation of one graviton loop corrections to the self-mass [1] to quantum-correct the field equation for a massless, conformally coupled scalar on de Sitter background. With the obvious choice for the finite part of …
Single graviton loop contribution to the self-mass of a massless, conformally coupled scalar on a de Sitter background Open
We use a simplified formalism to recompute the single graviton loop contribution to the self-mass of a massless, conformally coupled scalar on de Sitter background which was originally made by Boran et al., [Phys. Rev. D 90, 124054 (2014);…
Einstein-Gauss-Bonnet Gravity in Four-Dimensional Spacetime Open
In this Letter we present a general covariant modified theory of gravity in D=4 spacetime dimensions which propagates only the massless graviton and bypasses Lovelock's theorem. The theory we present is formulated in D>4 dimensions and its…