Blog

What’s all this buzz about quantum? Maybe you’ve heard it in science class or maybe in a sci-fi movie! No matter where you’ve come across it, you probably know it’s a bit strange, maybe confusing but also possibly an important part of the future. And all these things are true!

Physics is about using numbers to predict how things will move and interact. Just by going about your day, you have a sense of how balls will bounce or even how the Earth orbits the Sun. This kind of physics is called “classical”.

Quantum physics looks at the tiniest particles. At these scales our familiar classical physics breaks down and new effects pop up instead. These strange quantum effects tell us more about how nature works… and could help us invent new, powerful technologies – like quantum computers.

We think everyone can get their head around quantum, so we created a contest for adults to explain their favourite quantum effect using everyday language. Our expert judges picked the top 5 entries and this story from Michael Hall is one of them. Here he talks about how we literally can’t know everything. In the quantum world, measuring one property of an object like its speed or position, messes up what we know of its other properties.

As soon as we try to obtain accurate information about some property of an atom, light beam, or other physical system, we lose the ability to also obtain accurate information about other properties (or even to predict them). This is not because there is a mysterious limit to accessing information already “out there”, just waiting to be downloaded by our measurement devices. Instead, quantum mechanics tells us that any information we obtain about some property is, in part, randomly created by the very measurement interaction that we use to obtain it – we are, unavoidably, creators of content!

Further, we can create accurate information about one property only at the expense of not being able to create it about other properties — the different measurement interactions required to access these different properties are not compatible with each other. Trying to switch on more than one interaction at the same time creates noise, so that only a fuzzy joint picture of the properties can be obtained.

These effects are usually not important enough to be noticeable in the world that we see around us – we can usually get by perfectly well with a picture of reality in which the positions and speeds of atoms and molecules are a bit fuzzy, but not enough to matter when engineering bridges or moon landings. But it is precisely these effects that quantum engineers exploit in the amazing technologies that give us lasers, medical scanners and, hopefully one day soon, quantum computers.

Did you know that the United Nations has declared 2025 as the International Year of Quantum Science and Technology? To celebrate, the Australian Institute of Physics, Cosmos and Double Helix Extra put on the Quantum Explained Challenge. We will be sharing more of the top entries from the Challenge this year. Stay tuned!