Inflation

Lensing anomaly and oscillations in the primordial power spectrum

The latest analysis of the cosmic microwave background by the Planck team finds more smoothing of the acoustic peaks in the temperature power spectrum than predicted by ΛCDM. Here we investigate whether this additional smoothing can be mimicked by an …

Mimicking features in alternatives to inflation with interacting spectator fields

It has been argued that oscillatory features from spectator fields in the primordial power spectrum could be a probe of alternatives to inflation. In this work, we soften this claim by showing that the frequency and amplitude dependence of the …

Gravitational waves from global cosmic strings in quintessential inflation

The combination of non-minimal couplings to gravity with the post-inflationary kinetic-dominated era typically appearing in quintessential inflation scenarios may lead to the spontaneous symmetry breaking of internal symmetries and its eventual …

Hamiltonian approach to second order gauge invariant cosmological perturbations

In view of growing interest in tensor modes and their possible detection, we clarify the definition of tensor modes up to 2nd order in perturbation theory within the Hamiltonian formalism. Like in gauge theory, in cosmology the Hamiltonian is a …

Inflationary Magnetogenesis with Broken Local U(1) Symmetry

We propose a new mechanism for inflationary magnetogenesis in which the local U(1) symmetry is broken during inflation. Nevertheless it is shown that the U(1) symmetry is recovered on-shell. We find that it is free from both the strong coupling and …

CMB Scale Dependent Non-Gaussianity from Massive Gravity during Inflation

We consider a cosmological model in which the tensor mode becomes massive during inflation, and study the Cosmic Microwave Background (CMB) temperature and polarization bispectra arising from the mixing between the scalar mode and the massive tensor …

Strongly scale-dependent CMB dipolar asymmetry from super-curvature fluctuations

We reconsider the observed CMB dipolar asymmetry in the context of open inflation, where a supercurvature mode might survive the bubble nucleation. If such a supercurvature mode modulates the amplitude of the curvature power spectrum, it would easily …

Consistency relation and inflaton field redefinition in the deltaN formalism

We compute for general single-field inflation the intrinsic non-Gaussianity due to the self-interactions of the inflaton field in the squeezed limit. We recover the consistency relation in the context of the δN formalism, and argue that there is a …

Conformal frames in cosmology

From higher dimensional theories, e.g. string theory, one expects the presence of nonminimally coupled scalar fields. We review the notion of conformal frames in cosmology and emphasize their physical equivalence, which holds at least at a classical …

Inflationary Magnetogenesis with Broken Local U(1) Symmetry

We point out that a successful inflationary magnetogenesis could be realised if we break the local U(1) gauge symmetry during inflation. The effective electric charge is fixed as a fundamental constant, which allows us to obtain an almost …