Traditionally, quantum science has been a domain of fundamental research explored mostly by physicists. At the current state of the art the basic properties of the systems considered for realizing quantum hardware are understood at a great level of detail. Now, it becomes increasingly more important to develop quantum systems which are capable of harnessing their full potential and scale to a practically relevant size. But as the field matures, more and more application areas and engineering research challenges emerge.
The exciting possibilities in the field of new quantum technologies extend from quantum computing to precision timing, gravity sensors and imagers, cryptography, navigation, metrology, energy harvesting and recovery, biomedical sensors and imagers, and real-time optimisers all indicate the potential for quantum technologies to provide the basis of a technological revolution.
Along with these scientific and operational challenges to quantum, there are also significant engineering problems. As one might assume, the complicated nature of quantum science means developing quantum technology is very difficult. While research and development are underway, most quantum systems exist only in a laboratory environment, with many challenges to be overcome before these systems can operate at scale.
One major hurdle includes reducing “noise.” Noise is unwanted variations in data that interferes with computations and leads to errors.Noise is a problem for classical computers as well, but the sensitivity of qubits to external interference and their difficulty correcting errors that arise make it an especially difficult problem for quantum computers. Current attempts to overcome noise require laboratory settings that control for external vibrations and electromagnetic waves, and maintain very precise temperatures near absolute zero. Without solving the problem of noise, quantum systems can’t reach their full potential.
Another challenge is increasing the number of qubits on a processor chip. Like a traditional computer’s bit processor (i.e., 32-bit or 64-bit processor), quantum computers need qubit processors with hundreds or even millions of qubits to complete complex computations accurately. Current quantum computers possess roughly 50 qubits. However, according to Dr. Jonathan Dowling of Louisiana State University, current efforts to develop quantum computers are seeing the number of quantum bits on a quantum computer’s processor chips double every six months. “That is four times faster than Moore’s Law for classical chips, but the nature of quantum computers—[through] superposition and entanglement—means that their processing speed grows exponentially with the number of qubits. So, the processing power of quantum computers obeys double exponential growth,” Dowling noted. If this growth pattern continues, qubit processors could be capable of cracking one of the most widely used types of encryption, Rivest–Shamir–Adleman (RSA) encryption, and solving complex problems and simulations within the next decade.
But just as with classical computers, the chip is not the only important component. New quantum computers and other such technologies also require ecosystems of supporting software, hardware, and algorithms, just as traditional computers, encryption, communications, and other technologies do. Developing these additional items will undoubtedly come with their own scientific and engineering challenges. It is important to note that quantum technologies are still in the early stages of development, which means that as these technologies mature, new problems requiring new solutions will likely come up.
Quantum Engineering focuses on the practical implementation and application of quantum science and technology, such as quantum computing and simulation, quantum cryptography, or quantum sensing & imaging. Just as Systems Engineering through a focused strategy for the development cycle, has enabled development of hugely complex products and achieving massive industrial and economic impact, Quantum engineering is a revolutionary approach to quantum technology to enable the realization of quantum hardware through the development of device fabrication technologies and materials as well as control and read-out systems.
Freeke Heijman, Director of Strategic Development at QuTech explains, “Before we founded QuTech in 2013, the field in the Netherlands was more or less limited to scientists, including principal investigators who each had their own academic groups of students. They would grow knowledge, experiment, publish a paper in a scientific journal, and then move on. In order to move from science to engineering, which is the idea behind QuTech, you need additional, different expertise to come in: You don’t just want to do an experiment only once and publish a paper, you want to repeat it and optimize it, you want to develop technology that is scalable, cost-efficient, documented, and patented.
That is a different mindset. That involves milestones and not just academic freedom. Being in QuTech means you’re working as part of a bigger roadmap of a broader mission. It’s also about combining disciplines. We started with quantum physicists, and now also have teams of scientists in electrical engineering, computer science, and mathematics, but also social scientists working on user interfaces and societal impacts, people working on stakeholder management, people like me with a policy background, people with a communication background, and people with a background in philosophy. I even have a colleague working in the venture capital space, connecting venture capitalists and investors to startups’ ideas. As the ecosystem grows, we’re expanding to more various disciplines, which is fun.
The availability of talent is also one of biggest challenges for quantum, especially as a field which is scaling up so fast. And this holds true for AI and data science as well—for all of these innovations, there is a big need for a pool of people with a technology background. To keep up with the digital economy, we need to train individuals to equip them with the right skills, but we also need to attract talent and retain it in Europe, she said. That is another reason why we are based within a university, where there’s a continuous flow of students, and where we’re able to set up dedicated programs. For instance, we are building curricula for quantum information science and quantum engineering, so that we get new and more talent on board. The good news is that the interest in technology in general is growing: There are now many more students in computer science, data science, and in quantum physics.
Up until now quantum has been a very academic field, rather exclusive, gathering only the top five percent max—but that’s too small of a group. As quantum grows as an industry, it will also require other types of talents, and not just people who write papers in scientific journals. For us the challenge is therefore to train people on other levels while making them familiar with the technology, so as not to keep it only for the happy few that have the brains to grasp quantum physics. This is about opening up to other expertise and to people who may not have studied quantum mechanics early on.
One of the central pillars of quantum engineering is computation. The department of physics at ETH currently pursues research on different platforms for quantum computation. Significant momentum for the quantum engineering initiative is gathered in scaling-up two of the currently most promising and scalable platforms, namely quantum computing based on ions in traps and on superconducting electronic circuits. The first platform is based on ions trapped in ultra high vacuum which are manipulated with Lasers, radio and microwave frequency electromagnetic fields. The second platform is based on lumped and distributed circuit elements that are familiar to engineers, it is compatible with standard engineering concepts and approaches, and it provides a fertile ground for collaborative efforts.
Some of the hardest problems appear when investigating appropriate system concepts that finally lead to the design of viable quantum systems. Developing corresponding basic elements and integrating them into such a system is a formidable task, not only on the level of quantum physics but also on the level of engineering science. Many of the foremost challenges at hand are related to engineering quantum systems beyond the demonstration level. Here the goal is to make them technologically viable and to explore first applications with a potential commercial interest.
Quantum engineering—as this nascent field is now known—is a rapidly evolving area “in which quantum properties are essential to how a device or technology operates,” says Stevan Nadj-Perge, Assistant Professor of Applied Physics and Materials Science. It’s a relatively new term, but the field itself has deep roots in disciplines such as computer science, electrical engineering, materials science, and applied physics. Quantum engineering is now finally coming into its own. “In the same way that electrical engineering split from physics more than a hundred years ago, I think soon quantum engineering will split from more-classical engineering and physics,” says Andrei Faraon (BS ’04), Professor of Applied Physics and Electrical Engineering.
From quantum computers, currently quite specialized, but posited to eventually outshine today’s general-purpose super-computers, to novel devices for probing tough cosmological mysteries, the potential applications of quantum engineering are groundbreaking and far-reaching. But, as Austin Minnich, Professor of Mechanical Engineering and Applied Physics, notes, “it’s not just about industrial and techno- logical applications. It’s really about doing science in a completely different way.”
In many ways, quantum engineering has already had a tremendous impact on the world, even before the term quantum engineering was coined. Technologies like lasers, transistors, electron microscopy, and magnetic-resonance imaging were all developed based on concepts of quantum science. However, previous work does not depend on complex quantum interactions between particles that can result in even more bizarre emergent properties. Researchers have long known about these behaviors, but only recently have the science and technology advanced to a point where it’s conceivable to harness such behaviors.
“The grand challenge of quantum engineering in the 21st century is how to make use of the more subtle aspects of quantum theory—concepts like entanglement—which people like Bohr, Einstein, Heisenberg, and Schrödinger really struggled with,” says Painter. Successful utilization of quantum properties such as entanglement (the way particles influence one another’s states) and superposition (the ability of individual particles to exist in two states at once) is what is enabling a giant leap forward in quantum engineering today.
Quantum Engineering Initiatives
Quantum engineering programs, is now being established at leading universities world-wide have to explore the opportunities of quantum technologies. It encompasses both fundamental physics and the broad engineering skill-set necessary to meet the practical challenges of the future. A quantum engineer will be fluent in quantum mechanics, electrical and electronic engineering, systems engineering and computer science as well as other physical sciences.
“The science of things is getting smaller,” Guruswami Ravichandran, Chair of the Division of Engineering and Applied Science says. “We are also seeing a societal need for things to get smaller—and it doesn’t get smaller than the quantum scale, which is an area of historic expertise for Caltech.” According to Ravichandran, “the marriage of quantum science and engineering has the potential to result in technologies that can revolutionize all aspects of science.”
A new interdisciplinary graduate program at Colorado School of Mines will prepare engineers and scientists to contribute to the growing field of quantum technology – without the four- to six-year time commitment of earning a PhD. Starting in Fall 2020, Mines will offer graduate certificates and thesis/non-thesis master’s degrees in Quantum Engineering, with specialization tracks in hardware and software.
“Quantum technology could revolutionize computing, communication, sensing and more, but critical workforce shortages are threatening to hamper progress,” said Eliot Kapit, associate professor of physics. “You don’t need a PhD to make an impact in quantum engineering – you need quantum literacy, and this program is designed to bring students and working professionals up to speed on key concepts needed by industry today, including cryogenic equipment operation, programming quantum systems and quantum optics setup and operation.”
Core courses in the Quantum Engineering program will focus on four areas: the fundamentals of quantum information, quantum many-body physics, quantum programming and low-temperature microwave measurements for quantum information. Students will also get unique access to cutting-edge quantum instruments, including helium-cooled units and device measurements using microwave network analyzers, spectrum and signal analyzers.
“Students in this program will have a rare opportunity to get hands-on experience with helium-cooled units and low-temperature microwave measurement, key technologies for virtually all solid-state quantum computing systems,” Provost Richard Holz said. “Few programs in the world offer this sort of training in a classroom setting. Mines has made a major investment in recent years into growing the breadth and reach of its quantum research and this program is a natural next step.”
Innovative and ground-breaking work is happening at Caltech, thanks to the Institute’s unique strengths across the engineering and applied science disciplines and the EAS faculty’s deep connections to the sciences. Caltech has a rich history of breakthroughs in quantum science (consider the Nobel-winning work of Richard Feynman on quantum electrodynamics and Linus Pauling on quantum chemistry), and now it has become a leading incubator for quantum engineering as well.
Nadj-Perge is one of several faculty members working at the leading edge of quantum engineering. His research group is particularly interested in new materials for quantum computers. “One of the bottlenecks of doing quantum computation is that the exotic materials needed to push the field further have basically not yet been invented,” he explains. “All the practical materials that we have around have some limitations—and we don’t even fully understand those limitations.” Determining what the ideal materials would look like, and how to develop them, is therefore a major focus of his research. The results could greatly improve quantum devices and underlie the design of future quantum computers.
Another challenge in developing quantum systems is the need to take extremely quiet quantum signals and amplify them to the everyday scale. That is, we need to produce an output that “we can lay our grubby, classical hands on,” to borrow a phrase from renowned physicist and Caltech alumnus Carlton Caves (PhD ’79). Minnich’s group is addressing this challenge by improving the semiconductor-based micro- wave amplifiers often used in quantum systems. “We think we have a way to reduce the noise of those amplifiers to the lowest level physically possible,” says Minnich. “If we’re successful, it would greatly enhance our ability to probe nature at its very fundamental quantum limits.”
Minnich is also exploring quantum engineering from a theoretical perspective, using classical computers to simulate quantum phenomena. Whereas experimental approaches can produce data that might be interpreted in multiple ways, simulation can provide a more precise way of refining the predictions of a theory. Consider a difficult problem like the Schrödinger equation, which can’t be solved exactly. “Numerical tools go beyond what we can do with pen and paper by taking this equation and solving it under certain approximations,” explains Minnich. “This essentially provides a simulation of an experiment.” Such an approach can be useful, for example, when interpreting the emergent “quasi-particles” that result from the interactions of elementary particles in a material.
Light is another commonly used tool in quantum engineering, and it is the primary workhorse in Faraon’s laboratory. Operating near the fundamental limit of light- matter interactions, his group uses photons traveling through optical fibers to probe single atoms. The insights gleaned from his research could have major implications for quantum computing. Faraon notes an additional benefit of working with light: “It allows you to control quantum systems that are actually spaced quite far apart. Once a photon is in an optical fiber, the distance it travels—whether a meter or many kilometers—doesn’t really matter.” That means it may be possible to create inter- connected quantum systems that are delocalized over a very large area.
Painter’s research interests cover a broad swath of quantum engineering, from optical materials and devices to superconducting quantum circuits. One particular area of focus, however, is exploring what so-called “early-stage quantum computers” can do. “Quantum systems today still make too many errors to be fully useful,” says Painter, “but we can already start to build complex circuits capable of doing fairly mature computations.” Understand- ing how to best use quantum computers as they currently exist will undoubtedly facilitate important applications of this powerful technology in the near term. Looking further ahead, such insights will lay a critical foundation for the future as quantum computers continue to evolve.
Growing quantum engineering capabilities
NUS will take the lead in efforts to translate quantum science and technologies into industry-ready engineering devices and capabilities under the new Quantum Engineering Programme (QEP) launched by the National Research Foundation Singapore (NRF). The programme, which will see NRF invest $25 million over five years, was announced by Minister for Finance Heng Swee Keat during the opening ceremony of the annual Singapore Week of Innovation & TeCHnology (SWITCH).
The QEP will connect researchers in quantum science, photonics devices and system engineering with industry partners and local start-ups to grow engineering capabilities in three main areas — quantum secure communication, quantum devices and quantum networks — to achieve commercialisation outcomes. It will be helmed by Co-Directors Professor John Thong, Head of NUS Electrical and Computer Engineering, and Dr Kwek Leong Chuan from the NUS Centre for Quantum Technologies and the National Institute of Education. Dean of NUS Engineering Professor Chua Kee Chaing will chair the QEP Steering Committee.
Leveraging Singapore’s expertise in quantum technologies and engineering capabilities in communication, imaging, system design and device fabrication, the programme will create commercialisation opportunities in growing markets such as cybersecurity, global navigation systems, sensing technologies and diagnostic imaging.
“QEP is an exciting and ambitious R&D programme that will accelerate the translation of research in quantum phenomena into robust and scalable quantum technologies. By bringing together local and international expertise in engineering and quantum science, we aim to develop innovative quantum engineering solutions that could bring about economic and societal benefits for Singapore and beyond,” said Prof Thong.
Dr Kwek added, “Singapore has been actively involved in quantum research for about 20 years. The timely establishment of this new programme will attract more people working in engineering to contribute to these efforts, so that in the long run, we can play a greater role in commercialising quantum technologies.”
A QEP programme office to be hosted at NUS will launch calls for proposals in the identified research themes.