Ultra-cold mixtures
Quantum gases close to absolute zero are ideal systems to
study fundamental questions on decoherence, quantum physics and many body
physics. They are also optimally suited for simulating condensed matter physics
or analog gravity and studying ultracold collisions and ultracold chemistry. We
cool bosonic Caesium 133 and fermionic Lithium 6 to ultracold temperatures
where they form either a Bose Einstein Condensate or a degenerate Fermi sea.
To carry out this project we have built an experiment for degenerate Bose-Fermi mixtures for Lithium and Caesium atoms. Currently we can load about 10ˆ9 Lithium and 10ˆ8 Caesium atoms into our double-species Magneto Optical Trap (MOT). We have included in our system Feshbach coils, which produce magnetic fields up to 1200G and new gradient coils, which provide a gradient up to 55 G/cm. After the MOT we load each species into an optical dipole trap formed by a tightly focussed high power laser, where the gases are further cooled to quantum degeneracy. In this way we have obtained Li-Li molecular Bose-Einstein-Condensate and a degenerate fermi sea for Lithium.
To carry out this project we have built an experiment for degenerate Bose-Fermi mixtures for Lithium and Caesium atoms. Currently we can load about 10ˆ9 Lithium and 10ˆ8 Caesium atoms into our double-species Magneto Optical Trap (MOT). We have included in our system Feshbach coils, which produce magnetic fields up to 1200G and new gradient coils, which provide a gradient up to 55 G/cm. After the MOT we load each species into an optical dipole trap formed by a tightly focussed high power laser, where the gases are further cooled to quantum degeneracy. In this way we have obtained Li-Li molecular Bose-Einstein-Condensate and a degenerate fermi sea for Lithium.
A Quantum Integrated Light-Matter Interface
We are investigating ways to couple cold and ultra-cold atoms to photons delivered through a waveguide. In principle such a light and matter interface can act as a building block for photon storage, optical switching or quantum computational tasks. The waveguides are written by short laser pulses into normal glass, which locally changes the refractive index. We are studying surface waveguides, where surrounding atoms in a magneto-optical trap couple to the photons in the waveguide through the evanescent field. Another scheme achieves much stronger coupling, where the atoms are trapped optically in a void intersecting a waveguide. In third scheme we are testing an array of coupled cavities, where each cavity hosts a void with one or several atoms.
Our work is funded by an EUFET young explorers project and includes researchers from the University of Vienna, Dresden, Jena and Nottingham (theory and experiment). More details can be found on http://nottingham.ac.uk/quilmi/index.aspx |