On primordial cosmological density fluctuations in the Einstein-Cartan gravity and COBE data

TL;DR

This paper investigates how quantum spin fluctuations in Einstein-Cartan gravity could generate primordial density inhomogeneities, which are evolved to match COBE measurements of the early universe.

Contribution

It introduces a covariant, gauge-invariant approach to study density fluctuations in Einstein-Cartan gravity, linking quantum spin effects to observable cosmological inhomogeneities.

Findings

Quantum spin fluctuations trigger primordial density inhomogeneities.

Inhomogeneities evolve to match COBE data at decoupling.

Derived second-order differential equations for density evolution.

Abstract

We study cosmological density fluctuations within a covariant and gauge-invariant fluid-flow approach for a perfect fluid in the Einstein-Cartan gravity and derive the corresponding Raychaudhuri type of inhomogeneous coupled differential evolution equations of the second order. It appears that the quantum fluctuations of spin trigger primordial density inhomogeneities at the scale of weak interactions. These inhomogeneities are then evolved precisely to the value measured be COBE mission at the scale of decoupling.