Extended Theories of Gravity can be considered as a new paradigm to cure shortcomings of
General Relativity at infrared and ultraviolet scales. They are an approach that, by …

We review the holographic correspondence between field theories and string/M theory,
focusing on the relation between compactifications of string/M theory on Anti-de Sitter …

The Einstein equations with a negative cosmological constant admit black hole solutions
which are asymptotic to anti-de Sitter space. Like black holes in asymptotically flat space …

Our aim is to propose a theory which goes beyond the classical formulation of
thermodynamics. This is achieved by enlarging the space of basic independent variables …

This report gives a detailed account of relativistic quantum field theory in the grand
canonical ensemble. Three approaches are discussed: traditional Euclidean Matsubara …

Extending recent discussions of the Hagedorn transition in string theory, we argue that this
transition is a first-order phase transition with a very large heat (corresponding to a genus …

A cosmological wave function describing the tunneling of the Universe from" nothing" into a
de Sitter space is found in a simple minisuperspace model. The tunneling probability is …

Unimodular gravity (UG) is an alternative to general relativity (GR) which, however, is so
closely related to the latter that one can wonder to what extent they are different. The …

Quantum gravity seems to introduce a new level of unpredictability into physics over and
above that normally associated with the uncertainty principle. This is because the metric of …

Using the approach to black-hole thermodynamics initiated by Gibbons and Hawking, in
terms of the Euclidean Einstein action, I show that the canonical ensemble with elements of …