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Full-Text Articles in Physical Sciences and Mathematics
Fermi-Bounce Cosmology And Scale-Invariant Power Spectrum, Stephon Alexander, Cosimo Bambi, Antonino Marcianò, Leonardo Modesto
Fermi-Bounce Cosmology And Scale-Invariant Power Spectrum, Stephon Alexander, Cosimo Bambi, Antonino Marcianò, Leonardo Modesto
Dartmouth Scholarship
We develop a non-singular bouncing cosmology using a non-trivial coupling of general relativity to fermionic fields. The usual Big Bang singularity is avoided thanks to a negative energy density contribution from the fermions. Our theory is ghost-free since the fermionic operator that generates the bounce is equivalent to torsion, which has no kinetic terms. The physical system consists of standard general relativity plus a topological sector for gravity, and fermionic matter described by Dirac fields with a non-minimal coupling. We show that a scale invariant power-spectrum generated in the contracting phase can be recovered by suitable choice s of fermion …
Cosmological Consequences Of Classical Flavor-Space Locked Gauge Field Radiation, Jannis Bielefeld, Robert R. Caldwell
Cosmological Consequences Of Classical Flavor-Space Locked Gauge Field Radiation, Jannis Bielefeld, Robert R. Caldwell
Dartmouth Scholarship
We propose a classical SU(2) gauge field in a flavor-space locked configuration as a species of radiation in the early Universe, and show that it would have a significant imprint on a primordial stochastic gravitational wave spectrum. In the flavor-space locked configuration, the electric and magnetic fields of each flavor are parallel and mutually orthogonal to other flavors, with isotropic and homogeneous stress energy. Due to the non-Abelian coupling, the gauge field breaks the symmetry between left- and right-circularly polarized gravitational waves. This broken chiral symmetry results in a unique signal: nonzero cross-correlation of the cosmic microwave background temperature and …