Breaking news: Getting closer to BEC: T = 16 nK, PSD = 0.07 (27.06.2016).

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Welcome to the website of the first Slovenian cold atoms lab. We are setting up an experimental system for the preparation of a Bose-Einstein condensate (BEC) of cesium atoms.

BEC is a state of coupled bosonic atoms at a temperature near absolute zero. Under these conditions, a large fraction of the atoms occupy the lowest quantum state, while the quantum nature of atoms is manifested in the form of superfluidity. The superfluidity is a macroscopic phenomenon where the material behaves as a quantum fluid that flows without viscosity and is analogous to the phenomenon of superconductivity in solids. Because of this analogy the BEC can be used as a quantum simulator of solid state physics, e.g., to study superconductivity and, in more general, to explore the physics of strongly correlated electrons.

Using lasers and magnetooptical trap the cesium atoms in the ultrahigh vacuum are first slowed down and caught, and thus cooled to the temperature range of several hundred μK. In the next step, by means of Raman transitions, the cesium atoms end up in one of the well-defined low-lying energy states and the temperature falls below 1 μK. At the same time the atoms are caught in the so-called optical trap by a set of extremely powerful laser beams. The atoms are further cooled by evaporation, which lowers the temperature to the range of nK, which is low enough for the atoms to condense.

We established a few research guidelines, potential avenues for future research, where cold atoms will be used as an experimental method.

Experiments on the optical lattice: Atomic quantum gases in optical lattices are becoming the main simulating tool for solid state physics systems. Atoms play the role of electrons in solids, while their motion through the lattice can be well controlled. Using optical lattices one can explore the physics of strongly correlated electrons, which leads to superconductivity and magnetism. With the proper choice of optical lattice geometry it is also possible to explore frustrated magnetic systems, where theory predicts exotic ground states, such as the spin liquid.

Synthetic fields: Although the atoms are charge neutral, one can use laser light and magnetic field gradients to create effective scalar and vector potentials, which play the role of electric and magnetic forces on the atoms. Thus it is possible to simulate quantum phenomena known from solid state physics, e.g. the quantum Hall effect.

Nonequilibrium dynamics: While the physics of equilibrium phenomena is fairly well known and accepted, the physics of nonequilibrium phenomena is far less explored, is much less intuitive and it can lead to new findings, which might have far-reaching implications for general science, including the social sciences and economics. Because of their flexibility, cold atoms provide exceptional laboratory for the study of nonequilibrium phenomena.