Over the past decade, f (R) theories have been extensively studied as one of the simplest
modifications to General Relativity. In this article we review various applications of f (R) …

We give a comprehensive review of recent developments on using the pure spinor
formalism to compute massless superstring scattering amplitudes at tree level. The main …

The past two decades have seen transformative advances in cosmology and string theory.
Observations of the cosmic microwave background have revealed strong evidence for …

A bstract We consider higher derivative corrections to the graviton three-point coupling
within a weakly coupled theory of gravity. Lorentz invariance allows further structures …

We provide a derivation of holographic entanglement entropy for spherical entangling
surfaces. Our construction relies on conformally map** the boundary CFT to a hyperbolic …

A bstract The concept of the species scale as the quantum gravity cut-off has been recently
emphasised in the context of the Swampland program. Along these lines, we continue the …

Black hole solutions to Einstein's equations are examined in asymptotically flat N+ 1
dimensional space-times. First generalizations of Schwarzschild and Reissner-Nordstrøm …

Increasing evidence suggests that most of the energy density of the universe consists of a
dark energy component with negative pressure that causes the cosmic expansion to …

String theory is one of the most exciting and challenging areas of modern theoretical
physics. This book guides the reader from the basics of string theory to recent developments …

We calculate the complete low-energy effective action to quartic order in the bosonic fields
for the heterotic string. We find that, in addition to the term involving Ξ (3) found previously …