The Quantum Quest

Quantum science is having a moment. Stories about the potential of quantum seem to be everywhere these days, from network news to technical journals. But the history of quantum science actually dates back more than a century, when a small number of theoretical physicists identified strange phenomena at microscopic levels. Many brilliant scientists later, quantum is poised to transform technologies from computing to communications, bringing together physicists, engineers, computer scientists, chemists, and others.

What makes quantum a game changer? Its potential to tackle problems of mind-boggling complexity beyond the power of present-day computers, by harnessing the behavior that governs atoms rather than transistors.

Two phenomena at the atomic level — superposition and entanglement — are the focus of much current quantum research. Superposition is the ability of a particle to exist in multiple states or locations simultaneously; quantum entanglement refers to a connection between individual particles such that the state of one instantly influences the state of the other, despite any physical distance between them.

“We know that the power of quantum computation will be immense because superposition is scalable,” says Kai-Mei Fu, Virginia and Prentice Bloedel Professor of Physics and Electrical & Computer Engineering. “In the information age of today, a computational ‘bit’ can only exist in one of two possible states: 0 and 1. But with superposition, you could have a qubit that exists in two different states at the same time, making it possible to perform computations that our classical computers would need the age of the universe to perform.”

Charles Marcus, professor of physics and of materials science and engineering, believes the manipulation of quantum entanglement holds similar promise. “Once we are able to control quantum entanglement, the landscape of everything — data storage, mathematics, medicine, simulations, sensing, energy, and more — will be drastically changed,” says Marcus, who holds the Boeing Johnson Endowed Chair in Materials Science and Engineering.

Marcus’s goal is to build controlled quantum entanglement machines that can manipulate entanglement for specific purposes. Given the exquisite sensitivity of these manipulations, this is no small challenge.

“The problem is that these quantum states are fragile, and we need to build machines that can do seemingly contradictory things at the same time,” Marcus says. “The machine needs to allow rapid manipulation of quantum objects with an extraordinarily controlled touch. It’s a very difficult engineering problem. A lot of this field over the past 30 years has been trying to figure out how to build such a machine, and then how it can be used to address technologically relevant problems.”

Marcus notes that large tech companies like Microsoft and Google, as well as smaller companies like IonQ, are putting substantial resources into quantum engineering, expanding on research conducted at universities like the UW.

“Universities are all about scientific discoveries, creativity, and invention,” he says. “Once interesting ideas have demonstrated their value, we do a kind of handoff. Our goal is not to compete with industry but to work in partnership, where the university’s role is to explore, discover, follow clues, and examine alternatives — many won’t work out; that’s research — while the companies can do what they do best, which is to take the ideas that do work out and focus on scaling, performance, and reliability.”

Fu, whose research group studies the quantum-level properties of crystalline materials for potential applications in electrical and optical quantum technologies, compares the current moment in quantum technology to the early days of traditional computing — a time when computers were behemoths that held 10,000 vacuum tubes, before the transistor made smaller and smaller computers possible.

“Today’s quantum computers look something like those early computers,” Fu says. “But we finally have something that’s somewhat scalable, and that’s why there’s all this excitement right now. But if you look at the numbers needed for fault tolerance and for the computations that are going to impact humanity, people are still flying by the seat of their pants to get there. And there’s this huge space for innovation and creativity that the big companies can’t afford to explore as they are going down the linear chain of building these massive computers.”

The University of Washington has been a significant player in quantum research for many decades. In fact, two UW Arts & Sciences faculty from the Department of Physics — Hans Dehmelt and David Thouless — earned the Nobel Prize in Physics, in 1989 and 2016 respectively, for foundational research in quantum science. Today in Arts & Sciences, more than a dozen physics faculty have at least some portion of their effort focused on quantum research, along with colleagues in the Department of Chemistry. About half of them — including Marcus and Fu — have joint appointments in the College of Engineering.

Recognizing the importance of interdisciplinary collaborations in a field as complex as quantum, Fu serves as co-chair of QuantumX, an interdisciplinary hub for advancing and integrating research, teaching, and commercialization across all areas of quantum. Fu also is director of Accelerating Quantum-Enabled Technologies (AQET), a UW program funded through the National Science Foundation Research Traineeship Program to provide graduate students with cutting-edge training. 

Through AQET, a multidisciplinary group of UW faculty established the UW Graduate Certificate in Quantum Information Science and Engineering, which explores how the emerging field of quantum relates to other areas within science, technology, engineering, and mathematics. Undergraduate students can also delve into quantum through introductory quantum science courses. It’s a testament to quantum’s maturity as a field that concepts once understood only by a small number of theoretical physicists are now being shared with undergraduates.

“Quantum science is becoming accessible to more people as, over time, our pedagogy, our way of presenting things, becomes simpler and simpler,” says Fu. “At the UW, we’re very good at learning how to teach complex things that need to be taught.”

Undergraduates can also participate in quantum research in faculty labs alongside faculty, graduate students, and postdoctoral researchers. Both Fu and Marcus currently have undergraduates on their research teams, as do many other faculty. “The expectations are high, and the students have risen to every expectation,” Marcus says of his undergraduate team members, adding that he expects them to produce articles about their findings for publication in professional journals.   

While undergraduates come to quantum research green and ready to learn, postdoctoral students in quantum science arrive at the University with knowledge honed at other institutions. As researchers in UW labs, they contribute new ideas and perspectives. Beyond that, their presence has larger implications for the state of Washington.

“Postdocs are great for our research, but also for the quantum science ecosystem beyond the University,” says Fu. “When we bring people in at the postdoc level, they’re at the stage of life where they’re looking to settle down somewhere. And so hopefully their next spot after their postdoc is within Washington state, whether at a startup or working with some of the major companies involved in quantum information efforts in the state.”

The challenge is that postdoctoral fellowships are expensive. The UW recently established postdoctoral fellowships in quantum science named for Nobel Prize winners Dehmelt and Thouless — an important and exciting development. But continued investment, potentially including endowed support, will set the UW on an even stronger footing. Also on the wish list is more funding for quantum research from the State of Washington, particularly given the critical role of the Northwest region in advancing quantum technology.

“The Pacific Northwest has the right ratios of academic and small and large companies involved in information technology,” says Marcus. “Any regional hub pursuing cutting-edge technology needs a strong academic center at the core. That’s where most of the new ideas, as well as the new-idea creators, young people, come from. The UW is the engine driving this work in the Pacific Northwest.”

Read more about quantum research at the UW:

• Why quantum matters (UW College of Engineering)
• Accelerating a quantum future (UW College of Engineering)
• Asking quantum questions (UW Materials Science & Engineering)
• Q&A: UW research discusses the future of quantum research (UW News)
• Quantum Leap (University of Washington Magazine)