Caltech's Pioneering Quantum Hub Celebrates 25 Years
In September 2000, Caltech's Institute for Quantum Information and Matter (IQIM) was born (albeit with a different name, the Institute for Quantum Information, or IQI). At the time, it was one of the world's first centers dedicated to the study of quantum information science—a field that uses the laws of quantum physics to create better computers, sensors, and other probes for studying fundamental physics. Decades earlier, Caltech researchers foresaw that quantum information science would gain momentum, most notably the late Richard Feynman, who was the first to realize that solving the hardest quantum physics problems would require quantum machines.
IQIM, which is funded by the National Science Foundation (NSF), grew out of IQI and in 2011 became IQIM, an NSF Physics Frontiers Center at the leading edge of both theoretical and experimental studies in quantum information science.
Spiros Michalakis, staff researcher and manager of outreach at IQIM, described this name change from IQI to IQIM in a Caltech Heritage Project interview as a "visionary move," one that is still paying off: "We attach 'M'—matter—and it really mattered because … we started to have conversations about how you can implement certain things and how you can convert some of the theories into experiments. … It became such a powerful nucleating force on campus."
We sat down with John Preskill, the Allen V. C. Davis and Lenabelle Davis Leadership Chair and director of IQIM and the Richard P. Feynman Professor of Theoretical Physics, to talk about the origins and breakthroughs of the pioneering center.
When did you start to think about quantum information as a worthy pursuit?
Caltech has a proud history in quantum information going back to people like Kip Thorne [BS '62, the Richard P. Feynman Professor of Theoretical Physics, Emeritus] and Richard Feynman, who was the first to envision quantum computers. The field makes use of the special properties of entanglement to do things we couldn't do otherwise. What really changed the field was Peter Shor [BS '81], a Caltech alum, who, in 1994, proposed the idea that, at least theoretically, quantum computers could solve problems that are too hard to solve with classical computers, such as finding the prime factors of large numbers. And the late Jeff Kimble was already at Caltech working on things like quantum squeezing and getting single atoms to interact strongly with a single photon. The technology Kimble developed, in a somewhat different form, is still driving a lot of the progress in quantum hardware today.
Jeff and I were both excited about this field and started to have combined group meetings. We called ourselves the Quantum Computing Club. In 1999, we and others were asked by NSF to organize a workshop about the promise of the field and why it's relevant. The answer to that question back then is what is always driving me—the study of fundamental physics. Quantum technologies and quantum information ideas were a new way to explore nature. So, our idea was a good fit for NSF, which is the agency that focuses on curiosity-driven research.
What were the early days of the institute like?
IQI began as a theory institute in the fall of 2000, even though we had proposed that it include both theory and experiment. We had a vibrant visitor and postdoc program, but, at first, we had no space. Richard Murray [BS '85, the Thomas E. and Doris Everhart Professor of Control and Dynamical Systems and Bioengineering], who at that time was the chair of the Division of Engineering and Applied Science at Caltech, was very supportive and gave us space in Steele and Jorgensen where we worked until Annenberg opened in 2009. If it hadn't been for Richard, I'm not sure what we would have done.
When did you start doing experiments?
Jeff and I, along with Jim Eisenstein [the Frank J. Roshek Professor of Physics and Applied Physics, Emeritus] were really pushing for a Caltech initiative that would include more experiments. We called ourselves the three J's. We were on a mission, Jim, Jeff, and John, to get more support for quantum science on campus. Seed funding came from a [Gordon and Betty] Moore Foundation gift to Caltech, which emboldened us to propose an NSF Physics Frontiers Center, which was very competitive. They were only going to start one or two new ones out of over 50 proposals. In 2011, we won the award, becoming IQIM.
What did the shift from IQI to IQIM mean for the organization?
Having IQIM was really helpful for recruiting people, students, and postdocs, but also faculty. If you look at the faculty who are involved in quantum science on campus today, a lot of them were hired beginning in 2012, starting with the first six-year cycle of IQIM. Of course, faculty hiring is not directly tied to a federal grant, but the fact that we had this coherent center that cut across Caltech was very helpful for recruiting great people.
We also became highly interdisciplinary, with ties to physics, applied physics, computer science, electrical engineering, chemistry, and materials science. An important part of our vision is making deep connections between these different areas.
What kinds of science problems has IQIM been specifically addressing?
In general, we want to achieve better control of quantum systems. We are thinking about how to use entanglement to do interesting things like encrypted communications or more sensitive measurements, for example. And we use these tools to characterize complex phases of matter and their entanglement structure, and to illuminate how the phases of matter can be distinguished from one another. Our research has connections to quantum gravity, too [the attempt to unify quantum physics with general relativity]. Students who are studying quantum gravity now need to be well informed about ideas in quantum information. That wasn't true when IQIM began. Topics ingrained in the bones of computer scientists became of direct interest to the fundamental physicists.
Of course, how to actually build a quantum computer is at the forefront of a lot of our work, both theoretical and experimental. That spawned the creation of the AWS Center for Quantum Computing on campus, which is led by IQIM faculty members. Quantum hardware is plagued by frequent errors, so a key challenge is understanding how to make quantum computers reliable despite the faulty hardware. Just as important is understanding how quantum computers can be used to advance science and benefit society.
Speaking of quantum computers, when can we expect them to be up and working?
We have quantum computers now that are already valuable for scientific exploration, and I expect scientific insights enabled by quantum computing to occur more and more often. The earliest impact will be in condensed matter physics and materials science, then in chemistry and, eventually, in high-energy physics, including quantum gravity and early-universe cosmology. Those scientific applications will eventually lead to broader impact on society, but no one knows when. That's not likely in 10 years; it might take 20 years or longer.
Meanwhile, theorists like me will be thinking of new applications for the more powerful quantum computers of the future, of say 30 years from now. That sounds far away, but if we don't take on these challenges now, then the breakthroughs of tomorrow won't happen.
What else is coming up in the future for IQIM?
One exciting change will be the opening of the new Ginsburg Center for Quantum Precision Measurement building on campus. This will be an opportunity to bring together IQIM people who are now geographically separated from one another. My group and I will be moving in along with other physicists working on properties of quantum matter, atomic physics, and those using quantum devices to make more accurate measurements.
Another goal in Ginsburg will be developing clocks with incredible precision. Gravity changes how fast a clock runs. Already, atomic clocks are so precise that you can detect the effect of moving the clock up or down by a millimeter in the earth's gravitational field. Even more accurate clocks might be an alternative to LIGO for detecting gravitational waves, or they might be used to detect the gravitational effects of underground deposits of minerals, water, or oil.