Manipulation in Single Quantum System (Quantum Measurement Revisited)

The “optical cavity” for trapping atoms is a very powerful technique to trap different types of atoms and study the different possible states of matter: insulation, superconductivity, Bose-Einstein condensate. Generally, as the number of atoms trapped in the cavity is generally quite low, one has to cool-them to very low temperatures (approaching absolute zero via laser cooling and controlled evaporation) so that the their de Broglie wavelength becomes large allowing the quantum Bose-Einstein and Fermi-Dirac statistics come into play. One uses the Feshbach resonance to vary the interaction between the particles and reach the different states of matter. The most precise optical clock with a relative precision of approaching 10^-18 is based on an optical clock. Moreover, the QM entanglement process for a number of particles can be set up and followed. One has gone even farther by studying the dispersion relations and the different-sound velocities in these cavities.