Family fund keeps quantum researcher’s family together

29 August 2019:

CNBP researcher Dr James Quach is working on a quantum battery which, if he can demonstrate it works as the theory suggests, could revolutionise how fast we can charge electronic devices.But the work involves collaborations around the world, and with that lots of time-consuming travel, something that has become unappealing if it means leaving behind his wife, Susan, and 15-month-old daughter Abigail.

“I do have to travel quite a bit as part of my work, but I am trying to keep that to the minimum with the family.”

But an innovative family fund set up by CNBP is allowing him to take Susan and Abigail on some trips, with funding for flights and expenses so the family doesn’t have to separate.

“That’s great because Abby changes on a day to day basis. Only a few months ago she was like a baby, now she’s a toddler.” says James. “It is so exciting, watching them make the milestones and you hate to miss anything.”

In September Susan and Abigail will join him as he sets off for an 18-day visit to collaborators in the UK.

There he will work on an experiment that in time he hopes will demonstrate the concept of the quantum battery, which even by the standards of quantum mechanics, in an odd one.

“The notion is that, thanks to quantum entanglement, you can achieve quite a peculiar behaviour – your battery will charge faster the larger its capacity, which is highly counter-intuitive as, with conventional batteries, typically it will take longer to charge the bigger they are,” he says.

To test these ideas, James is constructing artificial systems that mimic the photosynthesis process. “Theoretically we know exactly why it happens. But what I’m doing is trying to demonstrate it in a laboratory, which hasn’t been done yet.”

The theory takes us deep into the looking glass world of the quantum: to go from an empty battery state to a state which is a fully charged state, you have to traverse an infinite number of states in between. In that infinite number of states, it still takes a finite time.

But with quantum entanglement in play, you can take a short-cut, and traverse an exponentially fewer number of states from empty to fully charged. That’s how it works, and the larger your battery is, the less states you have to traverse.

The mathematics of this is actually well-trodden ground. The number of states being defined by vectors in the Hilbert Space – a concept pioneered by German mathematician David Hilbert in the first few decades of the 20th century.

James’s work brings in nanoscale biophotonics following an experiment in 2007 which showed strong evidence that the photosynthesis process was a quantum mechanical one.

“Photosynthesis is all about capturing light. We’re mimicking this process to build our quantum battery,” he says.

James is originally from Melbourne. He completed his PhD at the University of Melbourne in 2013, and then spent two years at the University of Tokyo, and two years as a post-doc in Spain before returning to Australia and Adelaide University.

A collaborators on the experimental side is based at Sheffield University, where he is building the samples that we are going to use to test in Italy.

At the same time they are developing the experimental set-up in Adelaide.

There is still much work to do – and James also teaching as well as writing a paper on his battery. But the end result is potentially exciting.

“The idea that you can achieve essentially exponential charging rates in terms of the battery capacity means at some point you will essentially get a battery that effectively charges instantaneously,” says James.

“That’s all in theory but there are a lot of caveats right now. Probably the biggest one at the moment is the energy scales we are looking at is small.”

If the biological experiments he’s working on now are successful the next step is to see if they can be scaled up. James is already talking to a colleague in the University of Queensland to experimentally prove the quantum battery concept using non-biological compound of just four conducting qubits.

But James’s sights are set high. Another experiment for which he is seeking a grant would scale the process up using nanodiamonds.

“And there we’re using 10 to the 19 qubits, that’s 10 with 19 zeros…”