“Quantum mechanics is poised to give us a wholly new modern world.”
Tuesday, 19 December, 2023
Dr Steve Campbell (pictured) is a theoretical physicist and quantum mechanics researcher in the School of Physics at University College, Dublin. He has a PhD from Queen's University Belfast and worked at University College Cork, the Okinawa Institute of Science and Technology graduate university, the University of Milan and Trinity College Dublin before joining UCD in 2019, where his research has been supported through several prestigious grants from Science Foundation Ireland, Enterprise Ireland, the Irish Research Council, the John Templeton Foundation and the Alexander von Humboldt Foundation.
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The late Nobel laureate Richard Feynman famously said that If you think you understand quantum mechanics then you don’t understand quantum mechanics.
That was back in 1964 but “it’s still absolutely true” confirms UCD’s Dr Steve Campbell, of the mysterious branch of physics that deals with subatomic particles and energy. “I think I am nominally considered an expert in the area and I definitely do not understand sizable chunks of it.”
Quantum mechanics can be counterintuitive, he explains, describing the difficulty of measuring the position of a small particle, like an electron, for example.
“It's not that it's in place A or place B and we just don't know. It's that it's in both at the same time. Or it's in neither until we look. And these are two fundamentally different interpretations of this basic idea called the wave function that we haven't resolved yet.”
While open questions like this remain, quantum mechanics is, he clarifies, “very developed”, with the quantisation of energy having led to the digital technologies we use today.
“Our computers wouldn’t work without the laws of quantum mechanics being accurate. It’s just that they don’t leverage this funny superposition principle yet,” he says, referring again to the debatable whereabouts of those small particles. “So quantum mechanics has given us our modern world already. It's just poised to give us a wholly new modern world.”
With that in mind, Dr Campbell has contributed to Ireland's first national strategy for quantum technologies, Quantum 2030, launched last month by Simon Harris, Minister for Further Education, Research, Innovation and Science.
“Our computers wouldn’t work without the laws of quantum mechanics being accurate. It’s just that they don’t leverage this funny superposition principle yet."
“I got a grant from the Irish Research Council through their New Foundations scheme, which aims to look at areas which are of strategic economic and societal importance across the whole island of Ireland. So I was able to get all of the Principal Investigators of quantum research teams in Ireland into a room to discuss where we want to go as a country and what's important, and that information was fed into the strategy,” he says.
Some of these teams, like Dr Campbell’s, also research control and thermodynamics; others, quantum simulations and quantum computation. The strategy consists of five pillars, including excellent fundamental applied quantum research and building awareness of quantum technologies and real-world benefits.
What will those benefits be?
“The development everyone hears about is quantum computation. Everyone's like, ‘Okay, when am I getting my quantum computer? What's it going to be able to do for me?’ The bad news is you're probably not getting one, at least not in the next fifty years.”
But quantum technologies are currently having a “huge impact”, he says, particularly in the areas of sensing and communication. Quantum mechanics allows for the development of highly accurate sensors, enabling more precise measurements in various fields, such as medical diagnostics.
“If we want to test someone for cancer, quantum mechanics gives us the most accurate sensors allowable by the laws of physics.”
Meanwhile quantum communication networks are emerging as provably secure alternatives to traditional cryptography systems.
“Fundamentally, you cannot hack quantum crypto systems at all. The problem is they're very difficult to implement, but we have started developing them. There are commercial quantum cryptography companies now and you can get off-the-shelf quantum cryptography devices. We're developing quantum networks that allow for perfectly secure communications,” he adds.
“If we want to test someone for cancer, quantum mechanics gives us the most accurate sensors allowable by the laws of physics."
Bold claims have been made about quantum mechanics potentially enabling superfast financial market analysis, more precise weather forecasts and energy saving solutions to the climate crisis.
“What we expect quantum devices to be very good at is optimisation problems; so finding the optimal solution to a very difficult problem,” explains Dr Campbell, giving the example of ‘the travelling salesman problem’, for which the salesman’s fastest and most successful possible route must be plotted in advance.
“That is an incredibly difficult optimisation problem that quantum systems can maybe solve more efficiently by making use of this funny superposition principle. So if you can map a problem like financial markets or modelling of the weather or anything to do with climate into an optimisation problem, then the rationale is that quantum devices are going to be more efficient and better at solving the problem. That's why it touches on so many things,” he says, of quantum’s perceived potential. “Really, if we can develop quantum computers, that will be a game changing moment for us. Just as digital technologies have revolutionised the world, quantum computers will be a whole new way of processing information.”
Dr Campbell teaches an Introduction to Quantum Mechanics module to science students at UCD, from its history to its modern incarnations.
“Ireland has a surprisingly strong tradition in quantum physics,” he says, namechecking an Irish woman among its other pioneers like Paul Dirac and Erwin Schrödinger.
“Sheila Tinney was the first Irish woman with a PhD in mathematical sciences and she graduated from the University of Edinburgh where she worked with Max Born, who was also one of the founding fathers. So she probably introduced quantum mechanics to a lot of people in UCD - she was a lecturer here for about forty years.”
Listen to the (opens in a new window)podcast. More Rising Stars. More information (opens in a new window)here on Dr Campbell's research.