Modified gravity with a square root function of curvature

We present and analyze an f(R) gravity model characterized by a square-root form of the gravitational Lagrangian. The theory is consistent with local gravitational tests, which impose constraints on the models free parameter. We derive the constant-curvature solutions and determine the scalar-field potential and the scalaron mass in the Einstein frame. We show that the proposed model is free from matter instabilities. In addition, we investigate the inflationary dynamics of the model by evaluating the slow-roll parameters and the number of e-folds.