This article is dedicated to Claudio Bunster on the occasion of his 60th birthday. It is a great honor to take this opportunity to express my gratitude to him, who in my opinion has been the greatest national physicist ever, for his wise guidance and intrepid support through the years. As a Chilean, I can further tell that Claudio’s contributions have been well far beyond theoretical physics, helping our country to be ready to face future challenges through science. Gravity in diverse dimensions is a subject in which Claudio has done major c- tributions, encouraging in many ways the following work, that is being made along different fronts in collaboration with my colleagues Diego Correa, Gustavo Dotti, Julio Oliva and David Tempo. Thepursuitforwormholesolutions,whicharehandlesinthespacetimetopology, it is as old as General Relativity and it has appeared in theoretical physics within different subjects, ranging from the attempt of describing physics as pure geometry, as in the Einstein–Rosen bridge model of a particle [1], to the concept of “charge withoutcharge”[2],aswell asindifferentissuesconcerningthe Euclideanapproach to quantum gravity (see, e.g., [3]). More recently, the systematic study of this kind of objects was pushed forward by the works of Morris, Thorne and Yurtsever [4,5].

In the last few years modified gravity theories have been proposed as extensions of Einstein's theory of gravity. Their main motivation is to explain the latest cosmological and astrophysical data on dark energy and dark matter. The study of general relativity at small scales has already produced important results (cf e.g. LNP 863 Quantum Gravity and Quantum Cosmology) while its study at large scales is challenging because recent and upcoming observational results will provide important information on the validity of these modified theories. In this volume, various aspects of modified gravity at large scales will be discussed: high-curvature gravity theories; general scalar-tensor theories; Galileon theories and their cosmological applications; F(R) gravity theories; massive, new massive and topologically massive gravity; Chern-Simons modifications of general relativity (including holographic variants) and higher-spin gravity theories, to name but a few of the most important recent developments. Edited and authored by leading researchers in the field and cast into the form of a multi-author textbook at postgraduate level, this volume will be of benefit to all postgraduate students and newcomers from neighboring disciplines wishing to find a comprehensive guide for their future research.

Leading theorists share their important insights into the ongoing quest of theoretical physics to find a quantum theory of gravity.

Jacob Bekenstein, an Israeli physicist of the Hebrew University, Jerusalem, planted the seeds of a revolution of our understanding of space-time. Using conservative intuitive methods including time-old gedanken experiments, he discovered that black holes have thermodynamical properties such as entropy.Moreover, he found that their entropy was not extensive, unlike that of any other thermodynamical system considered before, but rather is proportional to the surface of their horizon. Furthermore, Bekenstein pioneered the study of black holes by focusing on their information content aspects. This led him to obtain bounds of a holographic nature on the amount of information that can be stored in a given region of space-time.This book contains a series of scientific and personal contributions by his contemporaries who recall the struggle against his ideas and then with them: the fate accompanying many revolutionary ideas. This is followed by original scientific contributions by many of the leaders of current research on black hole physics and holography. They have trodden his path and expanded it. The impact of Jacob Bekenstein's visionary ideas is just starting to be understood.

Stephen Hawking was widely recognized as the world's best physicist and even the most brilliant man alive–but what if his true talent was self-promotion? When Stephen Hawking died, he was widely recognized as the world's best physicist, and even its smartest person. He was neither. In Hawking Hawking, science journalist Charles Seife explores how Stephen Hawking came to be thought of as humanity's greatest genius. Hawking spent his career grappling with deep questions in physics, but his renown didn't rest on his science. He was a master of self-promotion, hosting parties for time travelers, declaring victory over problems he had not solved, and wooing billionaires. In a wheelchair and physically dependent on a cadre of devotees, Hawking still managed to captivate the people around him—and use them for his own purposes. A brilliant exposé and powerful biography, Hawking Hawking uncovers the authentic Hawking buried underneath the fake. It is the story of a man whose brilliance in physics was matched by his genius for building his own myth.

This volume examines the latest advances emerging from the theoretical exploration into the quantum mechanical structure of our universe. It will be of interest to researchers dealing with strings, quantum fields, gauge theory, and quantum gravity.

Il capitano generale lagrimo per allegrezza e nomino quel capo: Deseado, perehe l'avevamo gia gran tempo desiderato. Antonio Pigafetta Il Primo Viaggo in torno al Mondo I would like to take some poetic license in introducing this volume in a way that seems appropriate for a country, like Chile, that Iooks to the ocean. I believe it was Heisenberg who compared different times in physics with sailing a ship. He said that most of the time we keep our ships in port, or in the protection of a bay. But on a few occasions we go into the open sea, and those occasions are really the great times in theoretical physics, when everything can change. It does not seem totally unwarranted to hope that we are now entering one of those times. In that spirit, I would like to mention a wonderful book, which in English would be called something like Chile, Or a Crazy Geography.