Scalar current of created pairs by Schwinger mechanism in de Sitter spacetime

Ehsan Bavarsad; Clément Stahl; She-Sheng Xue

doi:10.1103/PhysRevD.94.104011

paper

Scalar current of created pairs by Schwinger mechanism in de Sitter spacetime

arXiv:1602.06556 · doi:10.1103/PhysRevD.94.104011

Abstract

We consider a charged scalar field in a $D$ -dimensional de Sitter spacetime and investigate pair creation by a Schwinger mechanism in a constant electric field background. Using a semiclassical approximation the current of the created pairs has been estimated. We find that the semiclassical current of the created pairs in the strong electric field limit responds as $E^{\frac{D}{2}}$ . Going further but restricting to $D = 3$ dimensional de Sitter spacetime, the quantum expectation value of the spacelike component of the induced current has been computed in the in-vacuum state by applying an adiabatic subtraction scheme. We find that, in the strong electric field limit, the current responds as $E^{\frac{3}{2}}$ . In the weak electric field limit the current has a linear response in $E$ and an inverse dependence on the mass of the scalar field. In the case of a massless scalar field, the current varies with $E^{- 1}$ which leads to a phenomenon of infrared hyperconductivity. A new relation between infrared hyperconductivity, tachyons, and conformality is discussed, and a scheme to avoid an infrared hyperconductivity regime is proposed. In $D$ dimension, we eventually presented some first estimates of the backreaction of the Schwinger pairs to the gravitational field, and we find a decrease of the Hubble constant due to the pair creation.

v2: 41 pages, 4 figures, matches published version

Scalar current of created pairs by Schwinger mechanism in de Sitter spacetime

Abstract

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