La principale difficulté pour vulgariser la physique quantique, c'est qu'on ne sait pas très bien comment en fabriquer des images dans notre monde. C… - Alain Aspect

In 1935, Albert Einstein, Boris Podolsky, and (EPR) wrote a now famous paper questioning the completeness of the formalism of quantum mechanics. Rejecting the idea that a measurement on one particle in an entangled pair could affect the state of the other—distant—particle, they concluded that one must complete the quantum formalism in order to get a reasonable, "local realist," description of the world. This view says a particle carries... locally, all the properties determining the results of any measurement... (The ensemble of these properties constitutes the particle’s physical reality.)

I think it is not an exaggeration to say that the realization of the importance of entanglement and the clarification of the quantum description of single objects have been at the root of a second quantum revolution, and that John Bell was its prophet. And it may well be that this once purely intellectual pursuit will also lead to a new technological revolution.

Now comes the Einstein–Podolsky–Rosen entangled state. Now I see faces, people saying, "Oh..?" Don't worry! When you go to the concert, you don't need to be able to read the music, to enjoy the music. ...So here... [are] equations. It's a pleasure for my colleague physicists. If you can't read the equation, listen to me. I'm not going to sing, but... listen to the words... the words are... a way of describing the equations, and you don't need to know the mathematics...