Abstract
The ninth and tenth lessons tackled the experimental aspect of this field of research by briefly describing a set of experiments recently carried out at ENS, in which qubits are carried by Rydberg atoms passing one by one through a superconducting cavity containing a small, well-controlled number of microwave photons. The entanglement between the atoms and the cavity field can be precisely manipulated, and simple quantum gates realized. These experiments show both the current possibilities and limits of quantum information processing, and highlight the considerable distance that still separates possible experiments from dreams of future applications.
