Wave-Particle Duality And Quantum Uncertainty - Two Sides Of The Same Mystery?

If you think of quantum physics in terms of information about a system, it is a lot less complicated, according to a new paper. In that context, features of the quantum world previously considered distinct  -  wave-particle duality and the quantum uncertainty principle - are different manifestations of the same thing.

Wave-particle duality is the idea that a quantum object can behave like a wave, but that the wave behaviour disappears if you try to locate the object. It's most simply seen in a double slit experiment, where single particles, electrons, say, are fired one by one at a screen containing two narrow slits. The particles pile up behind the slits not in two heaps as classical objects would, but in a stripy pattern like you'd expect for waves interfering.

At least this is what happens until you sneak a look at which slit a particle goes through - do that and the interference pattern vanishes.

The quantum uncertainty principle is the idea that it's impossible to know certain pairs of things about a quantum particle at once. For example, the more precisely you know the position of an atom, the less precisely you can know the speed with which it's moving. It's a limit on the fundamental 'knowability' of nature, not a statement on measurement skill.

A new paper written by Patrick Coles, Jedrzej Kaniewski, and Stephanie Wehner made the breakthrough while at the Centre for Quantum Technologies at the National University of Singapore shows that how much you can learn about the wave versus the particle behavior of a system is constrained in exactly the same way.