Starobinsky-Bel-Robinson gravity (2205.13172v3)

Abstract: A novel superstring-inspired gravitational theory in four spacetime dimensions is proposed as a sum of the modified $(R+\alpha R^2)$ gravity motivated by the Starobinsky inflation and the Bel-Robinson-tensor-squared term motivated by the eleven-dimensional M-theory dimensionally reduced to four dimensions. The proposed Starobinsky-Bel-Robinson action has only two parameters, which makes it suitable for verifiable physical applications in black hole physics, cosmological inflation and Hawking radiation in the early universe.