We review recent progress in massive gravity. We start by showing how different theories of
massive gravity emerge from a higher-dimensional theory of general relativity, leading to the …

We review in detail a number of approaches that have been adopted to try and explain the
remarkable observation of our accelerating universe. In particular we discuss the arguments …

The observable universe could be a 1+ 3-surface (the “brane”) embedded in a 1+ 3+ d-
dimensional spacetime (the “bulk”), with Standard Model particles and fields trapped on the …

We present an explicit calculation of the spectrum of a general class of string models,
corresponding to Calabi-Yau flux compactifications with h 1, 2> h 1, 1> 1 with leading …

This chapter presents a brief introduction to 'naturalness' problems in cosmology, and to the
cosmological constant problem in particular. The main focus is the 'old'cosmological …

Recent developments in the physics of extra dimensions have opened up new avenues to
test such theories. We review cosmological aspects of brane world scenarios such as the …

A bstract The previous studies of the island and double holography mainly focus on
codimension-one branes. This paper explores the island on the codimension-two brane in …

We construct a class of 4D'yoga'(naturally relaxed) models for which the gravitational
response of heavy-particle vacuum energies is strongly suppressed. The models contain …

We argue that accidental approximate scaling symmetries are robust predictions of weakly
coupled string vacua, and show that their interplay with supersymmetry and other …

Abstract Cosmologically active Brans-Dicke (or dilaton) scalar fields are generically ruled
out by solar system tests of gravity unless their couplings to ordinary matter are much …