Nicolas Menicucci, The University of Sydney
Quantum computers promise fast computation, but to be useful they need to be big -- really big. I will discuss recent theoretical and experimental breakthroughs in designing and building a huge quantum computer made out of laser light itself. The key component to such a quantum computer is a continuous-variable cluster state.
A cluster state is an entangled state that allows one to quantum compute just by making (adaptive) measurements on it, with the choice of measurements determining the computation performed. This is surprising because it means we can quantum compute simply by *looking* at a quantum systems in a particular way. The continuous-variable incarnations of these states are simple to make using lasers and can be scaled up with ease to gigantic sizes. In this talk, I will describe the basics of measurement-based quantum computing using continuous-variable systems, including a recent proof of fault tolerance using these resources. I will also report on their experimental realization, including the recent demonstration of a 10,000-mode (!) cluster state. Three orders of magnitude larger than the previous record of 14 trapped ions, this is the largest entangled state ever created to date in which every constituent quantum system is individually addressable, and it is the basic building block for what is potentially an ultra-large-scale quantum computer.