Professor Michelle Simmons AO
Boyer Lectures 2023
ABC Australia

Attendees of the fifth Solvay conference on physics, including Erwin Schrödinger, Max Planck, Marie Curie and Albert Einstein.

The 2023 Boyer Lecture series is called ‘The Atomic Revolution’ and is presented by Professor Michelle Simmons AO, a pioneer in atomic electronics and global leader in quantum computing.

Across the four lectures she’ll explore manufacturing at the atomic scale, why Australia is perfectly positioned to build the world’s first error-corrected quantum computer, and the importance of doubt in science. Since 1959, the ABC’s Boyer Lectures have sparked conversations about critical ideas.
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There is a very famous photograph, taken in 1927, at a conference in Brussels, Belgium, to commemorate the fifth Solvay Conference on Physics. At this meeting, 29 physicists were brought together to discuss the emerging theory of quantum physics. Of this group, an astonishing 17 had either won or would go on to win Nobel Prizes.

Max Planck was there, from whom we have Planck’s constant, which is one of the fundamental constants of physics. Werner Heisenberg was there: he’s the one who came up with the Heisenberg uncertainty principle, which tells us that we can know either the energy or location of a particle, but never both at the same time. Erwin Schrödinger, who gave us wave-particle duality and the famous Schrödinger equation was also present; as was Wolfgang Pauli, who dreamed up the Pauli exclusion principle to explain the quantum spin properties of electrons. And, of course, there was Albert Einstein, who won his Nobel Prize not for relativity but for his work on the photoelectric effect – a quantum phenomenon.

Of the 29 scientists present all were men, with one exception: the Polish-French scientist Marie Curie. Interestingly, she was the only person in attendance who had been awarded two Nobel Prizes. One in physics in 1903 … and the second in chemistry in 1911. Indeed, across all the decades up to the 1960s she was the only person in the world to hold two Nobels.

I love this photo. These were many of the brilliant core people who kicked off our understanding of quantum physics, all in one place. They were an extraordinary group, and this photo tells us so much about the way science used to be – and how different it is now.

Let me start with the obvious – and the superficial. Back then, science was undertaken by a small, close-knit community. It was predominantly male. It was largely European. Astonishingly, there were only two Americans in this group – Irving Langmuir and Arthur Compton. Curiously, and pleasingly, the only scientist from outside Europe or America was the Nobel-prize-winning Australian-born physicist, Lawrence Bragg.

None of this should be terribly surprising. It is simply a reflection of the way the world was. No matter what feelings one might have about who they were, or how they looked, or where they came from, these people made enormous contributions to our understanding of the world. In my laboratories, a hundred years later, we are thankful for the insights they’ve passed down to us, for we use their ideas every single day.

There are two additional points, however, that are much more intriguing to me than the observations above. First, it is striking what a sizeable proportion of this group was made up of theorists. All the big names in this photograph were theoretical physicists. Indeed, most of the big names in quantum physics throughout the twentieth century were theorists. The field has obviously had its experimentalists, but the glory went disproportionately to the ones who dreamed the theories, not the ones who proved them.

The other thing to note is that this was essentially a collective of academically-minded people. The Solvay Conference was funded by the Belgian chemist and industrialist, Ernest Solvay. But leaving this generous benefactor aside, there was no industrial presence. Those who participated were clearly focused on breaking down the fundamentals of quantum physics. This was not an event in which the participants were thinking of the applications or the practical enactment of their ideas.

Why do I say these things are intriguing? Because, a hundred years later, the world of quantum physics has been turned on its head. Today many young physicists, influenced by the history of their discipline, still perceive that there is more prestige in theory than in experiment. But whereas we already know a great deal about quantum theory, there is a vast amount still to be understood about its implications.

For instance, whereas we understand the theory of quantum computers, we don’t know whether we can practically build one. And advances in technology – such as our newfound ability to manipulate atoms – are empowering experimentalists all over the world to try. From my perspective, we are currently in the midst of a golden age of experimentation in physics. The discipline is no longer theory-heavy; it is now driving towards the practical control of nature at its most fundamental level.

The shift from academic focus to commercial focus is also quite astounding, though this flows naturally with the shift from theory to experiment. Throughout the twentieth century, quantum physics was one of the most esoteric fields. It was so esoteric, in fact, that some of its practitioners (people like Erwin Schrödinger) argued there was almost a spiritual aspect to it. Nowadays, by comparison, most of the leading groups trying practically to build a quantum computer are, in one way or another, embedded with companies.

Those of us in this position do still have our links to the academic world, but industry has become a natural place for us to work because the work is expensive, and because we are no longer simply discovering knowledge, but are trying to turn our discoveries into hardware that people will actually want to buy and use.

The world of quantum research is shifting beneath our feet, and as a participant in this change I think there are important lessons here – lessons relating to imagination, skills, and mindset – that tell us interesting things about the changing nature of science and what it takes for an individual, an organisation, a company or a country to succeed.

I think everyone understands the importance of imagination. All of science builds upon acts of imagination. A hypothesis is a creation of the imagination. A new theory is a product of imagination. Finding the solution to a technical problem in the laboratory requires imagination. Development work and engineering are also founded on imagination. You cannot build what you cannot imagine.

Particularly for a complex technological product, you must be able to think ahead and plan – and imagination is invariably the first step. Technological entrepreneurship takes tremendous imagination too. One must be able to envision a new product, to have some sense of who its customers might be and be able to imagine how you might deliver your product to them.

In every case, imagination is vital, but always with constraints. The theorist is welcome to imagine any sort of theory they like, but only the theory that explains experimental observation is valuable. And a theory only becomes genuinely exciting when you have the tools to test it.

I mentioned Democritus in an earlier lecture. He theorised about the existence of the atom more than 2,000 years ago, but his theory was largely ignored until we had the tools to test it.

The experimentalist, likewise, is constrained by the limits of what is physically possible and by what they can technically manage. The development engineer must curtail their imagination according to costs and supply chains, and other practicalities. The entrepreneur is only successful when their imagination captures the hearts and minds of investors and, ultimately, of customers.

So, while imagination is vital, neither the scientist, the technologist, nor the entrepreneur is a free-form artist working with a completely blank canvas.

When faced with practical constraints, in my experience, the critical factors that enable someone to turn imagination into an outcome are their skills and their mindset.

The importance of skills should be obvious. I would not ask a theoretical physicist to manage a semiconductor clean room – no more than I would hire a floral arranger to fix the plumbing in my home. The reason we have formal education and institutions like universities and scientific panels that assess our research proposals is because skills matter. Having a great idea is only ever the beginning of something; an idea is only meaningful in a practical sense if you have the skills to realise it; and no amount of wishful thinking can refute this fact.

What does this imply, given what I’ve observed about the shifting opportunities in quantum physics? In a way that probably wasn’t true in the last century, we now need more practical people with practical skills in the quantum domain. The theorists, of course, will still be there and they are still critically important; but we will need to complement their skills with far more microscopists, more measurement experts, more crystal growers, cryogenic specialists, laboratory technicians, more coders, and more highly-trained engineers.

We will also need more people who can straddle the divide between quantum research and practical application – that is, people who can bring commercial and entrepreneurial skills into the companies that are emerging in the quantum space.

And what about mindset? If it is one thing to have an idea, and another to have the skills to put it into practice, it is another thing again to have the determination to follow through and the motivation to do what really needs to be done.

This is something I have learned by observing those who work with atoms.

To work as an experimental physicist at technology’s frontier takes a very unusual mentality. Those who succeed are obsessively technological – that is completely obsessed with finding the best technological solutions to realise difficult goals. To make a success of things in this field, you have to be ruthlessly systematic. You can’t just try things at random and hope that something will work. I always try to teach my students and postdocs to change one variable at a time and see what really matters. That’s fundamental to doing experimental science properly, but it is also painstaking and exhausting.

This is a game in which you have to be extraordinarily persistent. You can’t succeed unless you work hard and pay meticulous attention to detail. And there is a difference here in mentality between the experimentalist and the theorist.

The experimentalist cannot sit comfortably in an office and dream about hypotheticals but must go to the laboratory each day prepared to battle hands-on within the hard confines imposed by an utterly implacable, recalcitrant reality. It’s not always a predictable reality either, for nature is full of surprises. At no stage does nature ever make things easy for the practical person who wants to test the limits of what is possible.

As a consequence, you also have to have the sort of mind that takes calculated risks, which can be hard, especially if you have colleagues who are sceptical about your ability to deliver – of which there is never a shortage in the scientific community. It is generally much easier, in science as in life, to do what everyone else is doing. Perhaps this is an area, along with their persistence, where the successful experimentalist shares the mentality of an entrepreneur.

Now, let me take you back to that famous Solvay conference in 1927. As I mentioned, there was one man present on that occasion with an Australian connection: Lawrence Bragg. Although he was born in Adelaide and educated at St Peter’s College and at the University of Adelaide, his involvement was not, strictly speaking, the manifestation of a vibrant Australian research scene in the early twentieth century. All his professional life was spent in British institutions. And this reflects the reality of the times, because, if truth be told, Australia was irrelevant to the great, early discoveries in quantum physics.

The question is, are we any different now? Or are we different enough? More to the point, do we have enough people in Australia now with the right combination of imagination, skills and mindset to succeed and to lead the world in the newly emerging quantum industries? I believe the answer to this question is yes – a resounding yes, in fact. That’s because quantum physics is not the only thing that has changed. Australia has changed too.

Let me tell you something astonishing. Back in 1959, at a time when commercial computers built with transistors were only just beginning to be sold, and Moore’s Law was years from being formulated, the Nobel Prize winning American physicist, Richard Feynman, one of science’s great visionaries, gave a lecture entitled ‘There’s Plenty of Room at the Bottom’.

The subtitle of this lecture was ‘An invitation to enter a new field of physics’.

Richard Feynman: You’ll find a summary of last lecture on here…

Right at the outset, he stated that what he wanted to talk about was “the problem of manipulating and controlling things on a small scale”.

Richard Feynman: Things are changing every day, but it’s perfectly obvious that by continuing studying these material there will be new and more wonderful things to make and to be able to do as time goes on…

He asked why we shouldn’t aspire to make circuits and machines at the level of perhaps 10 or 100 atoms. “I am not afraid,” he said, “to consider the final question as to whether, ultimately – in the great future – we can arrange the atoms the way we want; the very atoms, all the way down!”

What Feynman grasped was that achieving such a goal was a problem of practicalities not principles. He said, quote, “The principles of physics, as far as I can see, do not speak against the possibility of manoeuvring things atom by atom. It is not an attempt to violate any laws; it is something, in principle, that can be done; but in practice, it has not been done because we are too big.”

He also said, with considerable prescience, that quote, “When we get to the very, very small world – say of 7 atoms – they behave like nothing on a large scale, for they satisfy the laws of quantum mechanics …”

Richard Feynman: They do not behave like waves, they do not behave like particles, they do not behave like clouds, nor like billiard balls, nor like weights on springs, nor like anything that you know anything about…

“… So, as we go down and fiddle around with the atoms down there, we are working with different laws, and we can expect to do different things. We can manufacture in different ways,” end quote. Essentially, we can use quantum properties to our own advantage.

Richard Feynman: And that so, quantum mechanics maintains its existence … it’s perilous, but accurate existence.

I first read this wonderful lecture years ago and forgot about it. It was only recently that I rediscovered it and realised just how well we have been delivering on Feynman’s vision. As I explained in the first of my Boyer lectures, in my team at UNSW and in our company, Silicon Quantum Computing, what he was describing back in 1959 is precisely what we have done with our unique atomic manufacturing process: making wires and transistors and circuits with atomic precision.

And, as I explained in my second lecture, we have also been bringing all these various components together to control the quantum effects that emerge in this very, very small world (as Feynman puts it), with the goal of exploiting these effects to make the 21st century’s next frontier in computing: a quantum computer.

Sometimes, what seems like science fiction, actually does become fact – even if you have to wait 60 years! What strikes me especially about this, though, is that the idea has been on the table for a very long time – since 1959.

In Richard Feynman, it had an extremely eminent and articulate proponent. In theory, anyone could have done it, at least since the invention of the two core technologies that form the basis of our process: scanning tunnelling microscopy and molecular beam epitaxy. Yet only we did it, here in Australia. Why? Could it be because Australia has changed – because in the 21st century, Australia finally had the imagination, the skills, and the mindset to make something like this happen?

Given our history, our somewhat small population, and our location in the remote southern hemisphere, it is natural to assume that Australia can at best be a fringe player in any great, global technological endeavour. Yet this perception does not do us credit.

In quantum science and technology, especially in silicon quantum computing and in quantum optics, Australia is making contributions well beyond the size of its economy or its population. And the reason, I think – the secret of our success in this area – is the skills that have been built up through deliberate policymaking, combined with an advantageous mindset that already pre-existed in the Australian culture and psyche.

Science policy is perhaps not the most inspiring topic. Australian policymakers are rarely celebrated, but over the past twenty years our politicians and bureaucrats have done a fine job in supporting research in quantum physics and specifically in atomic electronics: via the Australian Research Council’s independent research fellowships; via the Australian Research Council’s Centre of Excellence program, which attracted so many outstanding quantum scientists into this country; and more recently through the support both the previous and the current federal governments have given to commercialising this research.

Important as they are, however, these policies have only worked because they were able to ignite something that already existed in the Australian mindset.

If I go back to the late 1990s, when I was working as a postdoc in Cambridge and wondering where I should go next, there was something about Australia that seemed uniquely attractive to me. Back then, I had applied for positions at three institutions: at Cambridge, at Stanford University in the US, and at UNSW in Sydney. When I was offered the job in Australia, I accepted immediately and pulled out of the other two. It was a choice that did not align with most people’s expectations. Indeed, when I arrived in Sydney, people kept asking me “why on earth did you come?”

Two considerations influenced me particularly. The first was academic freedom and the second was the ‘can do’ attitude of Australian researchers.

I knew that I wanted to pursue something ambitious and high risk, and I had learned that the structure in Cambridge was hierarchical and the research esoteric. I wanted to build something – something that hadn’t been built before and that might prove important and useful.

The UK offered years surrounded by pessimistic academics, who would tell you a thousand reasons why your ideas would not work. The US, more positively, offered a highly competitive environment, but one where you would need to fight both externally and internally for funds and be beholden to a senior mentor. Australia, by contrast, offered independent fellowships, the ability to work on large projects with other academics, and a ‘can do’ attitude to give anything a go.

I have never regretted that decision and, even today, when I see young Australians get all starry-eyed and status-struck about somewhere like Harvard or Oxford or Princeton, I remind them that there are freedoms here that are not always easy to find at other institutions.

Australian scientists are practical and understated; they are prepared to try things – to ‘have a go’; and they have a healthy scepticism about hierarchy and status. If an idea is sound, they’ll try it, even if there’s some self-important wise guy in America telling them not to. Even better, I’ve observed that those that come here from other countries are quickly infected with similar attitudes. For my money, that is an important part of the secret of our country’s success in quantum.

The challenge now is whether we have the mindset for the next steps. After all, pioneering a globally unique technology is one thing; turning it into a commercial success is another, and that is what will ultimately define the winners of the quantum age.

Sometimes I worry about this. When I sought to spin a company out of my university, there were some who were deeply uncomfortable about it. There are still many scientists here in Australia – just as there are in Europe and in the US – whose values make them uncomfortable about running companies for profit. It is not unusual for university researchers to believe that knowledge should be freely shared and open to all, which is clearly incompatible with operating or working in a deep-tech company. There are those, too, who are enthusiastic about commercialisation, but who’d rather do a course on the subject than simply get on and do it.

But I don’t think this is any longer the majority position. Today, our policymakers strongly support taking new ideas from the laboratory and out to the marketplace. Our universities are desperately keen to support commercial ventures based on their staff’s inventions. There are also many people among Australia’s new generation of researchers, who seem perfectly comfortable crossing sectors, and shifting out of academic environments and into commercial ones. In my own company, Silicon Quantum Computing, the culture emphasises outcomes not roles or positions or institutional affiliations. So, I’m optimistic.

In a world that needs practical experimental talent, our down-to-earth and pragmatic, ‘give-it-a-go’ culture is an asset. In a world that also demands commercial sensibilities, while we’re still learning, I also see hugely positive changes in the way we look at such things here in Australia. These changes should be welcomed and encouraged.

Funnily enough, I was fortunate to attend a Solvay Conference myself in 2022, on the physics of quantum information. These events have been happening roughly every three years since 1911. At the 2022 event, I recall a lot of discussion of how we might scale quantum computers so they can begin solving useful problems, and of the role industry will play in making this happen. Unsurprisingly, then, there were company people as well as academics present. There were a good number of experimentalists as well as theorists. And I’m delighted to report that, once again, there was an Australian present.

There is a very famous photograph, taken in 1927, at a conference in Brussels, Belgium, to commemorate the fifth Solvay Conference on Physics. At this meeting, 29 physicists were brought together to discuss the emerging theory of quantum physics. Of this group, an astonishing 17 had either won or would go on to win Nobel Prizes.