Jarryd Pla Published in 'Nature'

Monday 12 November, 2012
by Jonathan Billingham
Jarryd is the lead experimentalist on team that developed the qubit.

Jarryd Pla (New Collegian 2004-06) is the lead-author on a paper that was recently published in the scientific journal Nature. In the paper, Jarryd describes how the team he is a part of was able to both read and write information using the spin, or magnetic orientation, of an electron bound to a single phosphorus atom embedded in a silicon chip.

Scientia Professor Andrew Dzurak said in a media release, “For the first time, we have demonstrated the ability to represent and manipulate data on the spin to form a quantum bit, or ‘qubit’, the basic unit of data for a quantum computer. This really is the key advance towards realising a silicon quantum computer based on single atoms.”

Jarryd is is currently undertaking a PhDwhilst working on this project with team leaders Dr Andrea Morello and Professor Dzurak from the UNSW School of Electrical Engineering and Telecommunications. The team also includes researchers from the University of Melbourne and University College, London. In addition to being the lead-author on the Nature paper, Jarryd is also the lead experimentalist within the team.

Recently New College’s alumni magazine, New ‘n’ Old, contacted Jarryd to ask him about the research he is doing.

Jarryd, how did you end up as the lead-author on the Nature paper and the lead experimentalist on the project?

I think it was really just a matter of being in the right place at the right time. I started my PhD in 2009 with the Centre for Quantum Computation and Communication Technology, and by chance was given one of the Centre’s key projects to work on. It was a very ambitious project, and not knowing how ambitious it actually was, I jumped at the opportunity. I worked on it for four years with various other researchers and after a while it kind of just became my experiment. There were many late nights in the lab and sacrificed weekends but eventually we attained the results we were after, which lead to the publication this year in Nature.

What aspect of this project does your PhD gravitate around?

The goal of the project was to develop a quantum bit (or qubit), which is the basic unit of a quantum computer. In particular, we were trying to create this qubit using the same techniques employed by silicon computer chip manufacturers today, as this would give us a significant advantage when it comes to building a large-scale quantum computer. The way we achieved this was to implant a single phosphorus atom inside a silicon chip adjacent to a small transistor. We used the “spin” (a quantum mechanical property) of an electron in this phosphorus atom as our qubit. The spin can either point down or up, which forms the states of the qubit, much like in a conventional computer where a bit can be 0 or 1. We could use the transistor beside the electron to sense its direction and hence read out the quantum bit. The power of our qubit is that quantum physics allows the spin to be up and down at the same time. This was the key result we demonstrated, by irradiating the spin with microwaves we were able to put it in states where it was simultaneously up and down.

There were many people involved in this project. There was the team who fabricated the device, the people who placed the single phosphorus atom and then the group who performed the experiments. My PhD gravitated around the experimental side of things, i.e. actually performing the measurements and controlling the spin.

What personal characteristics do you think are invaluable to a student researcher in your field?

I know it sounds a little cliché, but a good student researcher is someone who is constantly asking the questions “how?” and “why?”. You really need a deep understanding of the underlying theories and concepts, and this is something you only get by asking questions. You also need a lot of patience and perseverance, it is almost guaranteed that your experiments are not going to work the first time around. And finally, I think you need to have a good imagination. A lot of my time is spent thinking about new things to try or ways to improve on things we have already done.

How did you find living at New College? Are there any memories that stand out that you would like to share with the other alumni?

I thoroughly enjoyed my years at New College! Certainly for me the best part about my time there was the friendships that I made. Even after having been gone for 5 years, I still keep in contact with many of my fellow collegians.

The memory that stands out the most actually occurred on my very first day at college. I was given the room with a fake wall! It was literally the size of a closet and I was told that I would have to store all of my clothes in the RA’s room. It was such a relief when I found out that one wall was a dud, the first thing I did was go and put my foot through it.