Professor Margaret Reid has spent her life studying the weird. Some have even called it the spooky. Every day Professor Reid delves into the strange and unexpected ways that tiny particles behave, building on theories developed by Albert Einstein and other eminent scientists nearly a century ago. Why is it, she wants to know, that according to a theory Einstein labelled Spooky Action at a Distance, two tiny, separated particles that are vast distances apart – sometimes even kilometres away from each other – both inexplicably react when only one is manipulated or disturbed?
The revelations from Professor Reid’s quest could have a profound real-world impact.
Already quantum theory has helped the world build lasers and microprocessors. And without this often bamboozling field of research, many 20th century tools, including computers and smartphones, would not exist.
A computer desk deep inside the Centre for Quantum and Optical Science at Swinburne is where Professor Reid spends much of her day. She’s a quietly spoken woman who, growing up, fancied she might like to enter the field of medicine. “To become a doctor you had to do all the sciences and maths,” she says. “Biology. Physics. Chemistry. They were compulsory.
“I always thought maybe I could transfer to medicine at some point but I never actually did in the end. When I started to work on some of these problems, I found it so interesting that I couldn’t break away. I was lucky I found a group of supervisors who had done some very, very interesting physics.”
Learning from the best
During her PhD, Professor Reid’s supervisor was noted New Zealand physicist Daniel Walls, a Fullbright scholar who’d gained his PhD from Harvard University under a Nobel Prize-winning scientist. Walls pioneered the study of ways that the particle-like nature of light can be controlled and made major contributions to the theory of quantum measurement. These were topics that grasped Professor Reid’s interest, too.
As a postdoctoral researcher she had the opportunity to be a visiting researcher at Bell Labs in the US state of New Jersey. She developed a theory for the first experimental observation at Bell Labs of “squeezed states of light” by showing how when light passes through a group of atoms, the quantum fluctuations in sections of light can be reduced below the quantum vacuum. Squeezed states of light are expected to help in the search for gravitational waves coming from space by the Laser Interferometer Gravitational-Wave Observatory (LIGO) in the US.
Gravitational waves, which were first hypothesised by Einstein in 1916, are believed to be ripples in the fabric of space and time produced by violent events in the distant universe. A statement by LIGO says: “Gravitational waves are emitted by accelerating masses much as electromagnetic waves are produced by accelerating charges. These ripples in the space-time fabric travel toward earth, bringing with them information about their cataclysmic origins, as well as invaluable clues as to the nature of gravity.”
Much of Professor Reid’s work sees her hunkered down creating complex mathematical equations. Like many scientists, hers has been a career of diligently edging forward. But there have also been pinnacles – and some of Professor Reid’s ideas are now used in physics research around the globe.
Professor Reid’s efforts may provide a tantalising real‑world application, potentially unlocking ways to better encode messages sent over the internet, which could lead to a vastly more secure world wide web. It is an increasingly important pursuit given the growth in cyber attacks and bugs such as the recent Heartbleed Flaw, which opened paths for hackers to steal information from a machine’s memory and left millions of individuals and a mind-blowing array of devices vulnerable to attack.
Although it sounds far-fetched, Professor Reid’s work could also contribute to the understanding of whether it might one day be possible to actually teleport clusters of atoms – including those that make up objects – from one location to another. But Professor Reid insists that real teleportation is not like this, but rather more like a very sophisticated fax. “There is a transfer of information using matter - not the actual matter itself. And the process, just like a fax, involves a telephone call between the sender and the receiver. Except at the quantum level, we can absolutely guarantee that there can be no other copy being sent anywhere else.“
To understand Professor Reid’s life work since she gained her PhD in New Zealand in the 1980s, you need to look back to the early 20th century when a group of scientists was developing quantum theory and challenging the belief that all things could be predicted as they behaved in a pre-determined way. It was discovered that when matter was broken down to tiny parts, the particles within them did unexpected things. Rather than act predictably, there appeared to be unseen “quantum leaps” from one location to another.
The discovery particularly troubled Einstein who believed there must be hidden variables that explained the apparent random behaviour of the particles, famously arguing “God does not play dice”. The related theory that previously entangled, but separated, particles both reacted to just one of them being disturbed didn’t impress Einstein either, triggering him to label it a “spooky” paradox. The challenge was to precisely measure the quantum fluctuations of the tiny particles to track their behaviour, in order to know if their movements could indeed be predicted. But the technology available simply was not precise enough – thwarting scientists’ attempts to better understand quantum mechanics and leaving, for decades, Einstein’s arguments an untested theory.
From 1960 onwards, the development of lasers meant tiny quantum fluctuations associated with particles of light, called photons, could be measured with enough accuracy that Einstein’s spooky paradox could be confirmed – for photons, that is. Many unanswered questions remain though, and the mission to uncover the secrets of quantum theory has continued for nearly a century.
Professor Reid has pioneered new ways of testing quantum mechanics. In the 1980s, she proposed testing Einstein’s paradox using pairs of photons generated from optics and crystals through a process called parametric down conversion. Her method has been realised at many institutions throughout the world.
A recent development in quantum mechanics that really has Professor Reid excited is the ability to cool atoms with lasers and keep them stationary while they’re being analysed. “We are able to do this right here at Swinburne Laboratories,” she says. “The atoms are trapped and they have no motion,” she says. “Normally the thermal motion of the atoms is so great that it is not feasible to measure their quantum fluctuations.”It’s this development that could allow Professor Reid to take Einstein’s Spooky Action at a Distance theory one step further and find out if a cluster of entangled particles that have been separated and shot off to different locations will also individually change if only one is manipulated. She has already explored this theory with rays of light and her findings could indeed lead to a more secure internet connection at your very own desk.
Recognising women in science
Professor Reid’s own contribution to quantum theory was recognised earlier this year when she was named a fellow of the Australian Academy of Science. In the science world, it’s akin to winning an Oscar. “It was a complete shock,” says Professor Reid, who is nevertheless happy to have her work praised so highly.
Professor Reid is hopeful that her elevation to the Australian Academy of Science will put her in a better position to mentor young scientists. “A big problem in science is the inadequate recognition given to the female physicists who made groundbreaking contributions last century,” she says. “This deprives young women of role models and perpetuates an ongoing myth that women are somehow weaker at science – especially physics and mathematics. This is completely untrue.” Professor Reid says young girls have a right to a truthful education that properly conveys the achievement of their gender. “Textbooks need to be fair, as does the very influential Nobel Prize committee. I get quite upset when I see that such injustice has been done to several generations of young women.
“In my field – physics – Emmy Noether derived the mathematical theorem that tells us why Newton’s conservation of momentum holds. Her work linking conservation to symmetry underpins much of modern theoretical particle physics. Yet, one has to search hard in textbooks to find her name. She should be there, I believe, in all the classic textbooks, side by side with the name of Newton.
“There are other major achievements by women in physics that are well‑known omissions from the Nobel Prize awards – Jocelyn Bell, Lise Meitner, Madame Wu. I think these omissions have had a very serious impact on young women.”