The Physics Society of Iran Iranian Journal of Physics Research 1682-6957 18 1 2019 11 26 Trace of energy-momentum tensor and gravitational backreaction of Schwinger scalars in 3D de Sitter spacetime Trace of energy-momentum tensor and gravitational backreaction of Schwinger scalars in 3D de Sitter spacetime 91 103 1337 10.29252/ijpr.18.1.91 FA E Bavarsad M Mortezazadeh Journal Article 2019 11 26 In this paper, we consider a massive charged scalar field coupled to a uniform electric field background in a 3 dimensional de Sitter spacetime. We consider the value of the dimensionless coupling constant of the scalar field to the scalar curvature of a 3 dimensional de Sitter spacetime equal to 1/8. We compute the expectation value of the trace of the energy-momentum tensor in the in-vacuum state and we show that using adiabatic subtraction regularization method the linear ultraviolet divergence is removed and a finite expression obtain. We investigate the behavior of the regularized trace for different intensities of the scalar field mass and the electric field. We show that the trace as a function of the electric field has a discontinuity at which it changes the sign. We show that for the case of a conformally coupled scalar field to the de Sitter spacetime the trace vanishes, and there is no trace anomaly. We discuss the gravitational backreaction effect of the created Schwinger pairs.   In this paper, we consider a massive charged scalar field coupled to a uniform electric field background in a 3 dimensional de Sitter spacetime. We consider the value of the dimensionless coupling constant of the scalar field to the scalar curvature of a 3 dimensional de Sitter spacetime equal to 1/8. We compute the expectation value of the trace of the energy-momentum tensor in the in-vacuum state and we show that using adiabatic subtraction regularization method the linear ultraviolet divergence is removed and a finite expression obtain. We investigate the behavior of the regularized trace for different intensities of the scalar field mass and the electric field. We show that the trace as a function of the electric field has a discontinuity at which it changes the sign. We show that for the case of a conformally coupled scalar field to the de Sitter spacetime the trace vanishes, and there is no trace anomaly. We discuss the gravitational backreaction effect of the created Schwinger pairs.   https://ijpr.iut.ac.ir/article_1337_e48e13207341b6bffb7fb1622282247b.pdf