Quantum physics

This is a simple explanation of quantum physics and the theories of superposition and many-worlds.

This one minute animated video from TVNZ demystifies some of the scientific and technical language.

Transcript

What is quantum physics?

It deals with the tiniest things we know, atoms and the particles that atoms are made of "subatomic" particles.

On such a tiny scale, things behave in strange ways that make us question what we think we know about the universe – because matter can behave like energy and energy can behave like matter.

This has led to an idea called ‘superposition’ which says if we don’t know the state of any given object – it is actually in all possible states at the same time – as long as we don't check!

To illustrate this, people use the famous analogy of Schrödinger's cat. If we don’t open the box to look, the cat could be alive or dead – or both dead and alive at the same time, according to quantum law.

Which suggests nothing is real until it has been observed!

Another interpretation of quantum physics is the many-worlds theory. This is the idea that every time an event has more than one possible outcome the universe splits into alternative worlds, with a new one for each and every potential outcome – meaning there could be an infinite number of other worlds existing in parallel to the one we think we know.

All this may sound like science fiction, but quantum physics is used in many every day applications, such as televisions and computers – and helps us understand the nuclear processes taking place inside the stars.

And that’s quantum physics.