Amplification of the primordial gravitational waves energy spectrum by a kinetic scalar in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si135.svg" display="inline" id="d1e55"><mml:mrow><mml:mi>F</mml:mi><mml:mrow><mml:mo>(</mml:mo><mml:mi>R</mml:mi><mml:mo>)</mml:mo></mml:mrow></mml:mrow></mml:math> gravity

V. K. Oikonomou