Gravitational Slip parameter and Gravitational Waves in Einstein-Cartan theory

Abstract

We study the evolution of scalar and tensor cosmological perturbations in the framework of the Einstein-Cartan theory of gravity. The value of the gravitational slip parameter which is defined as the ratio of the two scalar potentials in the Newtonian gauge, can be used to determine whether or not the gravity is modified. We calculate the value of slip parameter in the Einstein-Cartan cosmology and show that it falls within the observed range. We also discuss the evolution of the cosmic gravitational waves as another measure of the modification of gravity.

12 pages, 15 figures, References added

References in corpus (16)

• Unified cosmic history in modified gravity: from F(R) theory to Lorentz non-invariant models
• A direct empirical proof of the existence of dark matter
• Reconstructing Dark Energy
• A Parameterized Post-Friedmann Framework for Modified Gravity
• Measuring the dark side (with weak lensing)
• Anisotropic stress as signature of non-standard propagation of gravitational waves
• Recent Advances on Inflation
• Cosmology with torsion: An alternative to cosmic inflation
• Current constraints on the cosmic growth history
• On the Growth of Perturbations as a Test of Dark Energy
• How to optimally parametrize deviations from General Relativity in the evolution of cosmological perturbations
• Observables and unobservables in dark energy cosmologies
• Finite-time Cosmological Singularities and the Possible Fate of the Universe
• Spectrum of Primordial Gravitational Waves in Modified Gravities: A Short Overview
• The Einstein static universe with torsion and the sign problem of the cosmological constant
• On the torsion effects of a relativistic spin fluid in early cosmology