(Job 18381) Quantum Dynamics So quantum dynamics is a branch of physics that describes the microscopic world and what’s so interesting about it is that it behaves completely differently from the macroscopic or everyday world that we’re used to. So the everyday world we have an intuition about the laws of physics. If we drop something it will fall to the ground and smash, but at the microscopic level those sort of intuitions which we have really don’t apply. Amazing theories of quantum dynamics An example of how the quantum or microscopic world is baffling is something called the Heisenburg Uncertainty Relation. This basically says that it’s impossible to be able to predict everything about the world, no matter how good we are at measuring it. And more than that what the theory says is not just that we can’t predict the world, what the outcomes of our experiments are going to be, but in some sense those outcomes really don’t exist until we do the experiment. So it’s as if the uncertainty is not just an uncertainty in our mind, it’s as if nature itself hasn’t made up its mind about what’s going to happen until we do the experiment. Until we do nature can be in two minds about things. The most famous example of this is Schrödinger's cat, which is a thought experiment, so it’s not a real experiment, no cats get hurt. The idea of Schrödinger's cat is that the cat is shut in the box and after an hour you look and see whether the cat is alive or dead but it’s impossible to be able to predict which you’re going to see. But the interesting thing is that the theory says that not only can you not predict but before you look, in some sense the cat was neither alive nor dead, it was as if it was both and just didn’t make up its mind until you looked. How can we apply this knowledge? So quantum computing is a great example of how these crazy ideas about the microscope world can lead to fundamentally new technologies that could transform the way society works. And really this is just the idea of Schrödinger's cat applied. So the idea is that you have not a cat being in two uncertain possible states, but a whole computer being in an uncertain state about what computation it’s doing. Now this might sound like a bad thing but if you do set things up very carefully what you can have is this so-called quantum computer being able to do multiple calculations at the same time but in a way that when you finally come to read it out you just get one answer and it’s an answer that a normal, everyday computer couldn’t possible compute in a million years. Another application of the fundamental laws of quantum mechanics is in quantum communication, and here what’s interesting is that you can actually guarantee unhackable communication by using the uncertainty principle. So this is actually a technology which Page 1 of 2 is commercially available and here at Griffith University we’re working on this as well with the ultimate goal of building up a global quantum internet. What sort of work can research students do at the Centre? In the Centre for Quantum Dynamics we have students doing a wide range of research in both theory and experiment. As well as a quantum computing and quantum communication we have students looking at controlling the motion of quantum particles, atoms, electrons, etc. In particular we have the Australian Nanosecond Science Facility which lets us look at those motions on an unimaginably short time scale. One of the great things about research in this area is we have partners all over the world and in Australia and this is something that makes it a really exciting research area and keeps our students engaged. So it’s a great environment for PhD students, honour students and even bright undergraduates. According to John Nash, who is the man who inspired Beautiful Mind, it was trying to understand quantum physics that actually sent him mad, so that’s something we hope doesn’t happen with our students. Page 2 of 2