Fermionic Schwinger effect and induced current in de Sitter space

TL;DR

This paper analyzes the Schwinger effect for spin-1/2 particles in de Sitter space, revealing a negative induced current under certain conditions and noting the absence of IR hyperconductivity unlike scalar particles.

Contribution

It provides an analytical calculation of the fermionic current in de Sitter space and compares the phenomena with scalar particles, highlighting key differences.

Findings

Induced current can flow opposite to electric field at low field strengths.

Negative current depends on fermion mass and electric field strength.

IR hyperconductivity is absent for spinor particles.

Abstract

We explore Schwinger effect of spin 1/2 charged particles with static electric field in 1+3 dimensional de Sitter spacetime. We analytically calculate the vacuum expectation value of the spinor current which is induced by the produced particles in the electric field. The renormalization is performed with the adiabatic subtraction scheme. We find that the current becomes negative, namely it flows in the direction opposite to the electric field, if the electric field is weaker than a certain threshold value depending on the fermion mass, which is also known to happen in the case of scalar charged particles in 1+3 de Sitter spacetime. Contrary to the scalar case, however, the IR hyperconductivity is absent in the spinor case.