"From Quantum Devices to Quantum Machines"
James Colless, University of Sydney
Winner of the Royal Society of New South Wales Jak Kelly Scholarship Award for 2015
Date:December 2 2015:
Venue:University and Schools Club, 25 Bent Street Sydney
The Jak Kelly Award was created in honour of Professor Jak Kelly, who was Professor of Physics and The University of Sydney and UNSW and also President of the Royal Society of NSW; Its purpose is to encourage excellence in postgraduate research in Physics. It is supported by the Royal Society of NSW and the Australian Institute of Physics, NSW Branch. The winner is selected from a short list of candidates who made presentations at a recent meeting of the Australian Institute of Physics, NSW Branch.
Quantum computing, the use of quantum phenomena to process information, has begun the long journey from hypothetical possibility to real-world applications. In the same way that the theoretical development of quantum mechanics fundamentally changed the way in which we understand the universe, quantum computing offers the potential to revolutionize the way in which we are able to interact with it. In particular, this counter-intuitive nanoscale world of superposition and entanglement may allow previously intractable computational problems to be solved efficiently.
The fundamental building blocks of a quantum information processor are isolated quantum mechanical two-level systems known as quantum bits or ‘qubits'. Ideally such systems are easy to manipulate while being decoupled from noise in their local environment - goals that are often contradictory. In order to outperform their classical cousins at meaningful tasks quantum computers will conservatively require the control of thousands to millions of qubits. While this is still orders of magnitude less than the billions of transistors on a modern microprocessor, it is still far beyond what is currently possible.
The talk explored the complexity of scaling quantum processors and discusses new techniques and hardware developed to meet these challenges. In particular new methods of readout are developed that allow the dispersive sensing of single-electrons using integrated sensors and the capability to read out multiple qubits simultaneously. A scalable control scheme is also demonstrated allowing large numbers of qubits to be manipulated with a small number of input signals.
James Colless is a postgraduate research student at the University of Sydney currently undertaking his PhD under the supervision of Professor David Reilly. His research focus is readout and control techniques for GaAs spin qubits. James hopes his research will influence the design and fabrication of reliable multiqubit gates.