From Einstein's questions to quantum bits: a new quantum age?

Alain Aspect

In 1935, with Podolsky and Rosen, Einstein discovered what Schrödinger called entanglement", a phenomenon so strange that Einstein concluded that the quantum mechanics was "incomplete". Niels Bohr immediately opposed this conclusion, and the debate lasted until the death of these two giants of physics. Then, in 1964, John Bell produced his famous inequalities which would allow experimentalists to settle the debate, and to show that the revolutionary concept of entanglement is indeed a reality.

Based on this concept, a new field of research has emerged, quantum information, where one uses quantum bits, the so-called "qubits", which can be simultaneously in 2 states, just as a Schrödinger cat can be simultaneously dead and alive. Entanglement between qubits enables conceptually new methods for processing and transmitting information. Large scale practical implementation of such concepts may revolutionize our society (as did the laser, the transistor and integrated circuits, some of the most striking fruits of the first quantum revolution, which began in the 20th century).

Additional resources for this talk: slides and video.