Sandro Stringari – författare

The book is an introductory text to the physics of Bose-Einstein condensation. This phenomenon, first predicted by Einstein in 1925, has been realized experimentally in 1995 in a remarkable series of experiments whose importance has been recognized by the award of the 2001 Nobel Prize in Physics. The condensate is actually a new state of matter, where quantum-mechanical wave functions of atoms behave as coherent matter waves in the same way as coherent light waves in the case of a laser. The authors provide a theoretical presentation of the main concepts underlying the physics of dilute atomic gases in conditions of extremely low temperatures where quantum effects play a crucial role. The main effort is devoted to discussion of the relevant theoretical aspects exhibited by these systems, such as the concept of order parameter, long range order, superfluidity and coherence. The mathematical formalism is presented in a form convenient for practical use. The book develops the theory of Bose gases starting from the pioneering Bogoliubov approach and gives special emphasis to the new physical features exhibited by non-uniform gases which are produced in the recent experiments with magnetic and optical traps. These features include the determination of the equilibrium profiles, the collective oscillations, the mechanism of the expansion of the gas after releasing the trap, the interference patterns obtained by overlapping two condensates, the rotational properties revealing the effects of superfluidity (quantized vortices, behaviour of the moment of inertia), the Josephson-like phenomena associated with the coherence of the phase, the beyond mean field phenomena exhibited by quantum gases in conditions of reduced dimensionality (1D and 2D) etc. The book also discusses the analogies and differences with the physics of "classical" superfluids like liquid helium and introduces some of the major features of trapped Fermi gases at low temperature, pointing out the consequences of superfluidity.

Ultracold atomic gases is a rapidly developing area of physics that attracts many young researchers around the world. Written by world renowned experts in the field, this book gives a comprehensive overview of exciting developments in Bose-Einstein condensation and superfluidity from a theoretical perspective. The authors also make sense of key experiments from the past twenty years with a special focus on the physics of ultracold atomic gases. These systems are characterized by a rich variety of features which make them similar to other important systems of condensed matter physics (like superconductors and superfluids). At the same time they exhibit very peculiar properties which are the result of their gaseous nature, the possibility of trapping in a variety of low dimensional and periodical configurations, and of manipulating the two-body interaction. The book presents a systematic theoretical description based on the most successful many-body approaches applied both to bosons and fermions, at equilibrium and out of equilibrium, at zero as well as at finite temperature. Both theorists and experimentalists will benefit from the book, which is mainly addressed to beginners in the field (master students, PhD students, young postdocs), but also to more experienced researchers who can find in the book novel inspirations and motivations as well as new insightful connections.Building on the authors' first book, Bose-Einstein Condensation (Oxford University Press, 2003), this text offers a more systematic description of Fermi gases, quantum mixtures, low dimensional systems and dipolar gases. It also gives further emphasis on the peculiar phenomenon of superfluidity and its key role in many observable properties of these ultracold quantum gases.