The aim of the Center on Bose-Einstein Condensation (BEC) is to promote 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.

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. Together with the rapid progress of experimental investigations, new themes emerged in the theoretical side. 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 manipulation of matter waves, with interesting implications for 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. Other hot topics concern ultracold gases of atoms with long-range dipolar interaction, gases of dipolar molecules, and a variety of proposals to use ultracold atoms in optical lattices as quantum simulators, for the search of novel quantum phases.

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.

What is the BEC Center

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. In 2006, INFM became part of the Consiglio Nazionale delle Ricerche (CNR), which in turn was reorganized in new institutes. As a result of such a reorganization, since February 2010 the BEC Center has been finally incorporated into the Istituto Nazionale di Ottica (INO) of the Department of Materials and Devices. The Center is hosted by the Department of Physics of the University of Trento on the basis of an official agreement with 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 and by other funding agencies on specific projects. 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.

Opening a new experimental laboratory

The opening of a laboratory for ultracold atoms in Trento represents the novelty of the recent years. The motivations behind this choice are manifold. An impressive number of experimental groups worldwide are actively working in the field of ultracold atomic gases, but only a few of them are operating in Italy, namely at LENS-Florence and in Pisa. This field of research is still growing and there is no sign of saturation; indeed ultracold atoms have proven to be a versatile tool for exploring new physics in an interdisciplinary context, from atomic physics to quantum optics, statistical mechanics and condensed matter physics. Hence there is still plenty of space for novel experimental projects. This is also an opportunity for increasing the visibility and the attractiveness of the area of Trento, by properly combining the already existing theoretical activities with new experimental programs, thus opening new directions of research and a wider network of collaborations. With these motivations and with the support of INO-CNR, the Department of Physics of the University and the Provincia Autonoma di Trento, in 2010 the project has finally started. The project leader is Gabriele Ferrari.

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.

2010-11