Group activity on CPM
For several years, the Jagiellonian University team guided by prof. W. Gawlik has been studying various aspects of quantum coherences in different atomic systems allowing preparation of CPM. The research is conducted following two complementary techniques using: (a) ultra-cold atomic gases, (b) low-density atomic vapors in special cells at room temperature.
Ultra-cold atomic gases
Ultra-cold gas samples allow creation of robust CPM thanks to very slow decoherence. They can also be prepared in optical lattices which can be regarded as an artificial optical crystal where individual atoms are confined by an optical potential in a periodic structure with controlled symmetry, spacing (i.e. lattice constant), and population. Optical lattices allow studies of many phenomena of condensed-state physics with much better control than in traditionally obtained solid-state samples. Most important are here the possibilities of changing the lattice constant, controlling the particle interactions and external perturbations. In many cases it is possible to address individual lattice sites which opens various possibilities of applications in quantum information . At temperatures close to absolute zero, matter exhibits quantum degeneracy: bosonic matter undergoes phase transition to Bose-Einstein condensate (BEC) in which all particles have the same quantum properties, i.e. behave as a single quantum object.
It was in our team at the Jagiellonian University where the first Polish experiments allowing laser cooling and trapping of atoms below 1 mK were conducted. This expertise was seminal for the work continued at the National Laboratory of Atomic, Molecular and Optical Physics (KL FAMO) in Torun which resulted in the creation of the first Polish Bose-Einstein condensate at 70 nK and the finding of new properties of BEC-thermal gas mixtures. Presently, in addition to the National Lab where our team conducts and supervises the BEC research, there are two magneto-optical traps and one optical dipole trap in Krakow.
Low-density atomic vapors in special cells at room temperature
The complementary approach to reducing decoherence in CPM is to work with room-temperature atomic gas samples contained in specially prepared glass cells. This approach is very simple, yet allows very long coherence lifetimes and seems to be the most promising for wide applications. One such application is optical magnetometry. We have developed an optical technique that allows measurements of magnetic fields in a very wide range of intensities with unprecedented precision. This opens many new avenues, particularly in medicine and defense, as well as in fundamental research in physics, biology, geology, and astrophysics. A specific example is our joint project prepared with colleagues from the University of California at Berkeley to build a global magnetometer array, where synchronized magnetometers placed in several distant locations on the globe would be able to detect the correlation of minute perturbations/changes of the global magnetic field. The project is important for geo- and astrophysics but also for new science as a gravitation-wave or new/exotic particle detector.