Putting Quantum Weirdness to Work
The world might sometimes seem chaotic or strange — but look closer, and you’ll find it’s actually much, much weirder than you’d originally thought.
That’s a key lesson of quantum science, which over the past century has drawn back the curtain on a mind-bending array of sub-atomic shenanigans. Zoom in far enough, researchers have found, and you’ll see tiny particles behaving like waves — or teleporting from one place to another — or popping in and out of existence — or growing entangled and behaving identically no matter how far apart they travel. Weirder still, despite its name, quantum mechanics isn’t mechanistic: It reveals that randomness and uncertainty are baked into the fabric of the universe, and that attempts to pin down exactly what’s going on are, on some level, doomed to fail.
“Quantum science rests on the discovery that at very small scales, the laws of physics are completely different, and incredibly counterintuitive, and have very strange effects,” explains Stevens’ Igor Pikovski, Geoffrey S. Inman ’51 Assistant Professor in the Charles V. Schaefer, Jr. School of Engineering and Science and director of the Center for Quantum Science and Engineering (CQSE). “It turns out that’s an exceptionally powerful insight — because now, we’re learning to make use of those strange laws to solve problems, here in our own macroscopic world, in ways that would once have been inconceivable.”
For much of the past century, quantum researchers relied on mathematics and thought experiments rather than lab work. Researchers asked bizarre questions — such as whether each quantum measurement creates a new universe, or whether a cat locked in a box is alive or dead — and pondered their implications. Today, though, Stevens researchers are bringing quantum concepts into the real world, paving the way for ultra-powerful computers, game-changing medical devices, energy-efficient AI and countless other innovations. “We’re transitioning from thought experiments to actual implementations,” Pikovski says. “We know quantum is weird. But now we’re showing that we can put that weirdness to work.”
Getting Really Granular
The word “quantum” refers to the idea that the universe is fundamentally granular: Things that appear smooth and continuous, like energy or light or perhaps even space itself, are actually made up of quanta — tiny individual packets, like pixels on a screen, that collectively give rise to the macroscopic world. Light, for in-stance, comes in quantum parcels called photons, while electrons occupy only fixed quantum energy levels.
That insight helped resolve some of physics’ thorniest challenges, such as why light behaves both as a wave and a particle. But the quantum revolution also revealed the universe to be stranger than anyone had suspected. In school, you might have learned that sub-atomic particles — electrons, protons and so on — whiz around like tiny billiard balls, occasionally piling up into atomic structures. The truth is messier and more interesting.
Since 1925, when Werner Heisenberg used abstract mathematics to jump-start the study of quantum mechanics, researchers have viewed quantum processes as inherently probabilistic. An electron isn’t a billiard ball, neatly orbiting an atom’s nucleus; instead, it’s better thought of as a cloud of places where an electron could be. Every quantum system, in fact, is a “wave form” of possible configurations. (That’s how, in Erwin Schrödinger’s thought experiment, an unfortunate kitty, stuck in its box, can be said to be both dead and alive.) It’s only when a system is observed that possibility collapses into actuality — and even then, there are limits to what can be known. The more we learn about a particle’s location, for instance, the less we can know about its actions, and vice versa.
The inextricable randomness of quantum theory can be confounding; Albert Einstein famously resisted the notion, complaining that God “does not play dice.” Still, uncertainty can be powerful. Conventional computers, for instance, manipulate bits — strings of zeros and ones — to carry out calculations. But in a quantum computer, a bit can express all the possible values be-tween zero and one. That theoretically enables quantum computers to factor prime numbers at incredible speed, or complete in moments operations that would take billions of years using conventional computers. Such machines could turbo-charge innovation and unlock new forms of AI — but their sheer power could also prove disruptive. “A lot of the modern world is built on this kind of math,” Pikovski warns. “Quantum computing would change many things — it might mean, for instance, that all Bitcoin wallets would be instantly broken.”
Don’t rush to sell your crypto: For now, quantum computers remain incredibly hard to build. Quantum systems are easily disrupted and typically require near-absolute-zero temperatures; even then, they are inherently error-prone. So far, researchers are struggling to reliably knit together more than a handful of quantum bits — or “qubits” — into a circuit. “True quantum computing might still be decades away,” Pikovski says. “But it will be a real transition point for humanity once we get it working.”
Reaching Beyond What Nature Can Do
In the meantime, Stevens researchers are exploring other promising quantum technologies — and leading the way is Viola W. and Elbert C. Brinning Endowed Professor Yuping Huang, who founded the CQSE in 2017. His research bridges many different areas, from the development of room-temperature quantum chips, to single-photon optical systems, to random-number generators that could power unbreakable privacy technologies. He was also recently named CEO of Quantum Computing Inc., the first publicly traded quantum computing company. “Quantum theory explained how nature works,” Huang says. “But today, everybody is excited about quantum technology — because it could spark the next Industrial Revolution.”
Huang created the CQSE to accelerate that revolution, bringing together interdisciplinary researchers and engineers from across Stevens. “The hard part isn’t just the quantum physics — it’s all the things we need to do in non-quantum domains,” he explains. When Stevens launched the nation’s first campus-based hybrid quantum communications network in 2018, for instance, planners didn’t just need sophisticated quantum techniques to create the entangled photons used to send unhackable messages between the Babbio Center and the Williams Library. The project also required the development of high-speed circuitry and specialized signal processing to leverage quantum effects within a practical communication system. “That wasn’t something quantum scientists could solve — we needed electrical engineers,” Huang says. “It was important to bring all the stakeholders to the table, so we could learn from them and they could learn from us.”
One frequent CQSE collaborator is Professor Brendan Englot, director of the Stevens Institute for Artificial Intelligence (SIAI), who is partnering with Huang to explore quantum sensing applications. Huang’s team is developing quantum sensors that can literally see around corners, or peer through fog and other barriers; Englot’s group, meanwhile, is developing algorithms to integrate those sensors into real-world drones and robots. “Yuping is the quantum superstar,” Englot says. “Our job is to make sure that when his new technologies are ready to deploy, we have platforms they can be integrated with.”
Today, the CQSE comprises over 30 research groups from across Stevens, attracting well over $30 million from the Department of Defense, the National Science Foundation, the Alfred P. Sloan Foundation and others to explore areas ranging from quantum cryptography to the development of exotic materials. The common thread, says Stevens professor and physicist Svetlana Malinovskaya, is a focus on turning quantum phenomena into technologies with real societal impact. “With new technological advances — in lasers and precision control — quantum entanglement has matured into a working resource for quantum information technology,” Malinovskaya explains. “We are entering an era in which we can intentionally design and control quantum behavior, manipulating the properties of matter and light at their most fundamental level.”
Realizing this vision requires overcoming one of the central challenges of quantum science: stabilizing inherently fragile quantum systems so they can operate reliably outside laboratory idealizations. Researchers address this challenge through sophisticated quantum-control strategies, including ultrafast laser pulses lasting only a quadrillionth of a second, engineered to guide quantum dynamics with extreme precision. Done right, such methods unlock remarkable new capabilities: In one study, Malinovskaya’s team created quantum sensors capable of detecting subtle vibration al differences between healthy and cancerous cells. In another, Malinovskaya carefully arranged ultra-cold atoms to create quantum gates — a key component in quantum computers — that are 99.9% stable, reducing the resources needed to correct errors.
Quantum shapes every aspect of our world, including chemical and biological processes, so the potential applications are virtually limitless. “Quantum is everywhere,” Malinovskaya says. “But it’s only now, using current technologies, that we can reveal this microscopic world, and start putting it to work for humanity.”
The World's First Graviton Detector
Quantum technologies are driving theoretical break-throughs, too. “There’s an opportunity to close the loop and think about theory with fresh eyes,” explains Pikovski, who made headlines last year by showing that quantum techniques could potentially be used to detect gravitons, the elusive particles theorized to underpin gravity itself. “The accepted wisdom was that this would never be possible,” Pikovski says. “But by bringing quantum mechanics into human-scale experiments, we found a way to make it work.”
By focusing ultra-sensitive quantum sensors on resonators suspended in superfluid-helium, Pikovski realized, it should be possible to detect gravitational ripples as distant black holes smash into one another. By revealing the subtle granularity in those vibrations — the incremental steps in the apparently continuous vibration — it should be possible to detect individual gravitons. “We’d always thought gravity was impossible to detect at the quantum level — its effect on a single electron or atom is just too weak,” Pikovski says. “But we’re effectively turning a very large object into a single quantum system — and that can be used to detect gravitons.”
Thanks to a $1.3 million grant from the W.M. Keck Foundation — the first Keck award received by a Stevens researcher — Pikovski is now preparing to work with researchers at Yale to build the world’s first graviton detector. There’s no guarantee he’ll actually spot a graviton; Pikovski hopes the first detector will demonstrate the viability of quantum graviton detection, paving the way for the later development of more sensitive devices. “It’s just one example of what’s possible when we bring quantum laws into the experimental realm,” Pikovski says. “We’re seeing possibilities which were inconceivable 20 years ago — and there’s still so much out there to explore.”
That combination of visionary theoretical work and groundbreaking technological innovation makes Stevens a fertile space for quantum research, says Vice Provost for Research and Innovation Edmund Synakowski. “Application drives discovery, and discovery drives application,” he says. That approach is in Stevens’ DNA, Synakowski notes. In the 19th century, the Stevens family applied innovative theories to build the world’s first commercial steam ferries; today, it’s quantum researchers who are turning ideas into game-changing technologies. “It’s very aligned with the Stevens outlook. Our researchers actually build things,” says Synakowski. “We ask our faculty to work with an eye on big societal problems and challenges, and quantum has the potential to be at the core of solutions to so, so many of these challenges.”
The ultimate goal is to use Stevens’ leadership position to make quantum technologies far more accessible. The complexity of working with quantum phenomena — which requires costly materials, ultra-sensitive tools and advanced computing — has held the field back for too long, Huang says. Developing more affordable and compact quantum method-ologies will help push the benefits of quantum out into the world.
“We’re committed to democratizing this technology so that everybody can benefit,” says Huang. “Turning theory into products isn’t easy. But at Stevens, we’re now at a stage where we’re really making something happen.”
– Ben Whitford