Quantum Optics and Quantum Computers
Pierre Richard Dahoo, Philippe Pougnet, Abdelkhalak El Hami · 2021
Quantum computing is based on the properties of quantum mechanics. To process information, quantum computers use two-level quantum systems known as qubits (qubit means quantum bit). This chapter provides theoretical background and examples of applications, in order to help understand the operation of a quantum gate. It reviews the modeling of polarized light in quantum mechanics and the representation by the Bloch sphere of the states of a two-level quantum system. The chapter introduces the operating principle of a quantum computer. With a quantum measurement being able to modify the superposition of the states of the qubits, the measurements of the qubits are generally carried out at the end of the sequences of the algorithm. The chapter presents an exercise that uses Ramsey fringes and their application to the operation of a quantum gate.