Boson mixing and flavor vacuum in the expanding Universe: a possible candidate for the dark energy

TL;DR

This paper investigates how boson mixing in an expanding universe can produce an energy component with properties similar to dark energy, suggesting a potential link between quantum field effects and cosmic acceleration.

Contribution

It introduces a novel analysis of boson mixing in curved spacetime and demonstrates that the flavor vacuum behaves as a perfect fluid with dark energy-like properties.

Findings

Flavor vacuum energy-momentum tensor acts as a perfect fluid.

Equation of state varies between -1 and 1, matching dark energy in flat spacetime.

Boson vacuum could be a component of the universe's dark energy.

Abstract

We analyze the boson mixing in curved spacetime and compute the expectation value of the energy-momentum tensor of bosons on the flavor vacuum in spatially flat Friedmann-Lemaitre-Robertson-Walker metrics. We show that the energy-momentum tensor of the flavor vacuum behaves as the effective energy-momentum tensor of a perfect fluid. Assuming a fixed de Sitter background, we show that the equation of state can assume values in the interval [-1, 1], and, in the flat spacetime limit has a value -1, which is the one of the dark energy. The results here presented show that vacuum of mixed bosons like neutrino super-partners, can represent a possible component of the dark energy of the Universe.