Abstract
After setting out the general background and lecture plan, this first lecture will introduce the spin formalism ½, a model system for describing quantum information bits (qubits). It is used to describe qubits known as " stationary " such as the energy levels of an electron in an atom or in a defect in silicon or diamond, etc. We will show how to represent, manipulate and characterize a qubit, drawing parallels between quantum physics and quantum information. This common language makes it possible to describe the first ingredients of a quantum processor, as well as the operation of magnetic quantum sensors.
