Is Light a Particle or a Wave?


This post is by naval from Naval


God does not play dice with the universe

Naval: There’s a YouTube video in which Deutsch explains the famous quantum double-slit experiment, which is about particle-wave duality. Is light a particle or a wave? You pass it through a slit and, depending on whether there’s an observer and interference or not, it ends up in a wave pattern or as individual photons.

This is a famous experiment that has baffled people for a long time and caused them to revise their world view. It led Einstein to say, God does not play dice with the universe.

Brett: Einstein was a realist at the time when the founders of quantum theory were trying to develop a good explanation of what precisely was going on with these experiments in quantum theory. Einstein rejected all of them on the basis that they weren’t realistic, and he was right to do so because none of them made any sense.

To this day, none of the other alternatives make any sense.

Now, Einstein didn’t know about the multiverse. We had to wait until Hugh Everett in the 1950s was able to devise a simple, realistic way of understanding quantum theory. But if I go back to this idea of the double-slit experiment, it is often claimed that particles have a duality to them: Sometimes they’re particles, and sometimes they’re waves.

For example, the electron, given certain experiments, will behave like a particle. And in other experiments, it behaves like a wave. People (Read more...)