The aim of the Center on Bose-Einstein Condensation (BEC) is to promote theoretical research on the various phenomena related to Bose-Einstein condensation and to the physics of cold atomic gases in traps. Since the first observation of BEC in cold gases in 1995, the study of ultracold gases has become an emerging area of research at the crossing point of several disciplines, including atomic, molecular and optical (AMO) physics, statistical mechanics and condensed matter physics. BEC has been presently achieved with Rb, Na, Li, K, H, He, Cs and Yb. More than twenty groups worldwide have reported experimental production of BEC and there is a vast range of theoretical and computational activity.

Interest in BEC derives from several factors. BEC is the only known phase transition taking place also in the absence of interactions, its origin being purely quantum mechanical. Thus it is one of the cornerstones of quantum statistical mechanics. Before 1995 BEC had only been explored in strongly interacting systems, such as superfluid helium, where the effects of the interaction mask some crucial features of BEC. The dilute gas experiments of the past years have made it possible to compare in a systematic way experimental data with the predictions of first principle theory. The theoretical approaches have been mainly based, in the first years, on the use of Gross-Pitaevskii theory for the order parameter and have proven quite successful, especially to predict the behaviour of these systems at low temperature, both at equilibrium and out of equilibrium.

Despite this great success there remain a number of important problems of conceptual relevance which are presently the object of intense research activity. These include, among others, the dynamics of the condensate at finite temperature, the kinetic phenomena in the presence of BEC, the nucleation of quantized vortices, the dynamics of vortex arrays, the nature of the phase transition for reduced dimensionalities and in the presence of array geometries, the emergence of new quantum phases, like number squeezed and Schroedinger cat states, the occurrence of new topological structures in multicomponent condensates, the behaviour of BEC for large scattering lengths and the role of Feshbach resonances, the occurrence of chaos in the dynamics of BEC, the fluctuations of the condensate for small samples, the theory of the order parameter beyond mean field, the mechanisms of decoherence of the phase, the stability of solitons and vortex rings. The remarkable property exhibited by BEC of generating a macroscopic population of atoms in the same quantum state has also opened up the new field of coherent atomic optics. This has already led to the development of coherent matter waves sources (the so called atom laser) to be employed for interferometry. This is a major step towards the ultimate control of fundamental characteristics of atomic beams with important applications like precision spectroscopy, frequency standards, atomic gyroscope, atom lithography and holography, sensors, etcetera.

In the last few years an impressive activity in the field of ultracold gases has also concerned the study of Fermi gases. Despite the initial difficulty in cooling such systems experimentalists have been quite successful in obtaining highly degenerate samples, providing new concrete perspectives in the study of Fermi superfluidity, including the long sought BCS-BEC crossover. At present Bose-Einstein condensation of molecules (pairs of fermions) has been succefully achieved and new challenging experimental and theoretical perspectives are characterizing the international scene. Finally, BEC research boosted several important applications in related branches of physics. A few examples concern the use of BEC to generate gases with very high non-linear optical susceptibility, where light propagates at extremely low speed and the perspective of using ultracold gases to implement logical operations with important links with the field of quantum information.

The growth of the BEC field has crucially benefited by the cooperative efforts of experimental and theoretical groups in many laboratories. The aim of the BEC Center is to reinforce the interdisciplinary links of the theoretical research. On the other hand the Center is intended to reinforce the scientific collaborations between theoretical and experimental activities, establishing direct and systematic links with the main laboratories in the world.

Start

The BEC Center was established by the Istituto Nazionale per la Fisica della Materia in Trento in June 2002, following a selection made by an international panel. The Center is hosted by the Department of Physics of the University of Trento on the basis of an official agreement with INFM (now CNR). Scientists belonging to the BEC Center include CNR researchers as well as personnel from the University, together with a large number of PhD students and post-doctoral fellows, who are partly funded by CNR and partly by the University. The budget of the BEC Center is provided by CNR and by the Provincia Autonoma di Trento (PAT) on the basis of official agreements. The research activity of the Center is also supported by the Italian Ministry of Research. The Trento BEC Center is expected to contribute to the the worldwide development of research activities in the field of ultracold gases through a series of scientific publications, the reinforcement and the creation of international collaborations, the organization of workshops and conferences, as well as through the training of young scientists.
An inauguration meeting was organized on 14th and 15th March 2003.

Scientific Reports

2002-04

The scientific report of first two years (June 2002 - May 2004) is avaliable on-line (pdf file, 2440 Kb, 118 pages). The report provides an overview of the main activities on Bose-Einstein condensation and related topics. Most of the scientific work carried out at the Center can be naturally classified according to the following research lines: Rotating quantum gases, Quantum gases in low dimensions, Excitations in Bose-Einstein condensates, Dynamics of BEC in optical lattices, Breakdown of coherence in optical lattices, Ultracold Fermi gases, Bose-Fermi mixtures, Numerical simulations in quantum gases. The two following research lines are just at the beginning: Quantum information applications, Interferometry and sensors with ultracold gases.

2004-06

The scientific report of the second two years (June 2004 - May 2006) is avaliable on-line (pdf file, 4360 Kb, 153 pages). The report provides an overview of the main activities along these lines: Rotating quantum gases, Low dimensions, Excitations in Bose-Einstein condensates, Ultracold atoms in optical lattices, Ultracold Fermi gases, Quantum Monte Carlo methods, Casimir-Polder force, Quantum optics and solid state physics, Quantum information processing, Matter-waves interferometry.

2006-08

The third scientific report (June 2006 - May 2008) is available (pdf file, 1710 Kb, 144 pages). It gives an overview of the main activities along these lines: Fermionic superfluidity and BCS-BEC crossover, Polarized Fermi gases, Quantum Monte Carlo, Rotating gases and quantized vorticity, Nonlinear dynamics and solitons, Ultracold gases in optical lattices, Dipolar gases, Semiconductor microcavities and exciton-polarons, Quantum optics and quantum fields, Casimir forces, Matter-waves interferometry, Quantum information processing.