“Physics is my entire life, I love the problem-solving side of it,” says Arjun David Rao, 23. “It’s not just that I love the theory and can derive equations all day, it’s being presented with a particular problem – it’s so much fun to then go and solve it. The feeling you get when you solve it is unlike anything else.”

That love of physics took Arjun to Imperial College London, where he undertook a combined bachelors and masters with a focus on astrophysics. He got to work at a research institute in Spain’s Canary Islands, where he helped build large-scale computer models of galaxies and dark matter, “which was really interesting,” he recalls.

Arjun in USYD hallway
Arjun David Rao, Sydney Quantum Academy PhD scholarship recipient at the University of Sydney.

But after listening to friends rave about quantum computing, he signed up for a summer research project in the field, and was sucked in. “I did hackathons and attended talks, and just started really getting into it. I was like, ‘You know what? This is cool. I can see myself doing this.’ So, I switched in my fourth year to quantum information.”

That’s when he discovered Q-CTRL, a quantum technology company in Sydney backed by IBM and led by charismatic quantum physicist Professor Michael Biercuk at the University of Sydney. He approached Biercuk about joining the start-up; but with no roles vacant, Biercuk suggested the next best thing: do a PhD in his Quantum Control Laboratory.

“The more I looked at a PhD at the University of Sydney, the more I was completely convinced,” he smiles. “Then Michael told me I could get funding through the Sydney Quantum Academy (SQA), and it was a no brainer after that.”

Since landing an SQA scholarship for his PhD and arriving in Sydney in July 2021, he’s been dazzled by the breadth of possibilities.

"A huge attaction for me was SQA's links to industry. It's not just pure academia - there are lots of people involved in government and industry. You get a flavour of both, and I like that."

Arjun David Rao

At the Quantum Control Laboratory, Arjun is exploring how to improve the fidelity of entangling logic gates within a trapped ion information architecture. This is a design for a quantum computer in which calculations are carried out by performing tightly controlled operations on minuscule charged particles. The design has proved itself to be a leading hardware platform for quantum computing, with excellent performance and real potential for scaling up to large numbers of qubits, or quantum bits. 

“You are literally stopping and confining an ion in 3D space, just using electric fields, then shining lots of laser at it, to make the ion do lots of funky, interesting things,” he says. "The lasers can induce the ion to ‘entangle’ with another ion so that the following operations performed on one affects the other. With this toolkit, the ions can then be used as qubits.” 

Entangling pairs of qubits with extreme accuracy, or fidelity, is essential to harness the power of quantum computing, eventually allowing the control of multiple entangled qubits that can perform individual operations for computing, simulation, and networking.

“We’re trying to push for some of the highest fidelities, and my PhD is trying to entangle them in the best way possible,” he adds. “It isn’t just academic or just to create a paper – the system that I’m working on and improving is what Q-CTRL will use to run some of their theory and experiments, and double-check that their quantum tools are working.”

Arjun handling quantum technology including green

Arjun’s PhD also requires using various machine learning and optimisation methods. “I get to do the experimental, the theoretical, and coding – so, I get a flavour of all three. Some mornings I’m down in the lab tweaking lasers and optical breadboards, and then another afternoon, I’m upstairs in the lab hard coding up an entire experiment. For me, the combination is perfect.”

While he could have joined any number of companies or research groups in Britain or the United States, Arjun is still glad he chose Sydney – largely because of SQA. “The Sydney quantum scene is exploding; it’s clear Sydney is going to be one of the quantum hubs of the world,” Arjun says. “And SQA is outstanding – it creates a community of PhD students from all the centres, which is very rare. It opens the door to anybody doing quantum work, and that just changes the scene.”

– Wilson da Silva 

 Studying a quantum PhD at the University of Sydney

The University of Sydney’s $150 million Nanoscience Hub houses the Quantum Control Laboratory, Quantum Integration Laboratory and Quantum Theory Group.  The Quantum Control Laboratory explores new ways to control quantum systems for use in quantum computing, simulation, and sensing. The Quantum Integration Laboratory probes the quantum interactions between light, electronics, and atoms embedded in crystals. Whereas the Quantum Theory Group explores a wide range of fundamental and applied questions ranging from the foundations of quantum mechanics to how to build practical quantum technology. The University of Sydney also hosts the global research node of the Microsoft Station Q network which is focused on engineering interfaces between classical and quantum systems for more powerful quantum machines. See more.

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