Polarized backgrounds of relic gravitons

  title={Polarized backgrounds of relic gravitons},
  author={Massimo Giovannini},
  journal={Physical Review D},
The polarizations of the tensor modes of the geometry evolving in cosmological backgrounds are treated as the components of a bispinor whose dynamics follows from an appropriate gauge-invariant action. This novel framework bears a close analogy with the (optical) Jones calculus and leads to a compact classification of the various interactions able to polarize the relic gravitons. 
3 Citations

Effective energy density of relic gravitons

The energy density, the pressure and the anisotropic stress of the relic gravitons do not have a unique gauge-invariant and frame-invariant expression since the equivalence principle ultimately

Primordial backgrounds of relic gravitons

Flat spectra of cosmic gravitons in the nHz and audio bands

  • M. Giovannini
  • Physics
    Journal of Cosmology and Astroparticle Physics
  • 2022
The spectra of the relic gravitons are customarily normalized in the low-frequency domain where the signal of the concordance paradigm is expected to peak and this is why their contribution to the



Spectra of relic gravitons and the early history of the Hubble parameter.

It is shown how one can reconstruct the time dependence of the very early Hubble parameter and matter energy density from a measured frequency-dependent spectrum of relic gravitational waves.

Effective field theory for inflation

The methods of effective field theory are used to study generic theories of inflation with a single inflaton field. For scalar modes, the leading corrections to the R correlation function are found

String theoretic axion coupling and the evolution of cosmic structures

We examine the effects of the axion coupling to RRon the evolution of cosmic structures. It is shown that the evolutions of the scalar- and vector-type perturbations are not affected by this axion

Graviton Creation by Small Scale Factor Oscillations in an Expanding Universe

We treat quantum creation of gravitons by small scale factor oscillations around the average of an expanding universe. Such oscillations are predicted both by modied gravity theories with a term

Quantum Fields in Curved Space

This book presents a comprehensive review of the subject of gravitational effects in quantum field theory. Although the treatment is general, special emphasis is given to the Hawking black hole

Quantized Gravitational Wave Perturbations in Robertson-Walker Universes

We consider the theory of quantized gravitational wave perturbations in the three types of Robertson-Walker universes. In a gauge analogous to the Coulomb gauge in electrodynamics it is possible to

Chern-Simons modification of general relativity

General relativity is extended by promoting the three-dimensional gravitational Chern-Simons term to four dimensions. This entails choosing an embedding coordinate v_\mu -- an external quantity,

Cosmological signature of new parity violating interactions

Are there any manifestations of parity violation other than those observed in weak interactions? A map of the cosmic microwave background (CMB) temperature and polarization will provide a new

Post-inflationary thermal histories and the refractive index of relic gravitons

We investigate the impact of the post-inflationary thermal histories on the cosmic graviton spectrum caused by the inflationary variation of their refractive index. Depending on the frequency band,