Looming behind Regenstein Library is a bronze, mushroom cloud–shaped sculpture—Henry Moore’s Nuclear Energy. Installed in 1967, it now seems like an inconspicuous part of the campus landscape. In reality, it symbolizes the first step in UChicago’s deep and complex history as a pioneer in nuclear and quantum physics
A framework for quantum physics originated in the early 1920s, when European physicists began to notice that particles behaved differently at small scales. The laws of classical physics were not holding; physicists, noticing those flaws, sought a remedy. Through the work of a few extraordinary individuals, the resulting forms of science found their way to UChicago, which then became the site of some of the most important experiments in the history of nuclear and quantum physics.
Just last year, the Palo Alto–based startup PsiQuantum announced its plan to construct the Quantum Computer Operations Center, a 300,000-square-foot quantum computing structure aiming to host a total of one million qubits, on Chicago’s South Side. Quantum computing is known as an up-and-coming technology with potential applications in scientific, financial, and industrial fields. But it is just the latest chapter in Chicago’s rich history in nuclear and particle physics, dotted with events like the first-ever synthetic nuclear chain reaction, the participation in the Chicago Quantum Exchange (CQE), and a student building a nuclear reactor for Scav. The city’s longstanding reputation as a pioneer in quantum science begins at the University of Chicago.
Fermi in Chicago: Turning Theory into Results
In 1938, Enrico Fermi, often referred to as the architect of the nuclear age and one of the greatest physicists of all time, emigrated from Italy to escape Benito Mussolini’s rising fascist regime. After spending time at Columbia University, Fermi, trained in all forms of theoretical and experimental physics, moved to Chicago, ready to reshape the quantum landscape.
His work laid the foundation for more accurate, cohesive, and mathematically justified theories of particle motion.
In a biography of Fermi, Herbert Anderson—who had been his colleague first at Columbia University and then at UChicago—described Fermi’s practical, realistic approach to science: “Fermi was in his 20s [in the 1920s] when physics was undergoing one of its major advances. The theory of quantum mechanics was developing rapidly.… Fermi was less interested in the more formal aspects of the theory than in its use in explaining what was going on.”
Like other physicists of his time, Fermi used the groundbreaking equations recently developed by theorists to conduct concrete experiments, uncovering many eye-opening truths about the physical world. In the 1920s and 1930s, he theorized about atomic collisions between charged particles and the existence of a new class of subatomic particles with special, useful properties (which were later discovered and named fermions in his honor).
In 1932, following the discovery of the neutron, experimental nuclear physics became an extremely fertile field. This would be crucial for Fermi’s later exploits in nuclear science at UChicago’s Metallurgical Laboratory (Met Lab).
Chicago Pile-1: The First Ever Man-Made Nuclear Chain Reaction
On December 2, 1942, under the bleachers of UChicago’s Stagg Field, Fermi directed a research team in an experiment that achieved the first ever man-made nuclear chain reaction.
They set up a pile of graphite bricks embedded with layers of uranium and a series of cadmium rods methodically inserted into the pile.
Previously, Fermi and his colleague Anderson had reached an interesting conclusion. By applying quantum mechanics to the behavior of uranium, they had found that uranium atoms, when bombarded by neutrons, split and emit even more neutrons at high energies. This causes the uranium atoms hit by those neutrons to split as well, creating a chain reaction.
His team removed the structure’s rods one by one, with “close watch being kept on the intensity [of neutrons in the system].” Fermi had calculated that for the chain reaction to occur, eight feet of the last rod needed to be removed.
“Actually when about seven feet were removed the intensity rose to a very high value but still stabilized after a few minutes at a finite level,” Fermi wrote in a research report (available in the Regenstein Library’s Special Collections). “It was with some trepidation that the order was given to remove one more foot and a half of the strip.”
Fermi wrote that the intensity began increasing slowly “until it was evident that it would actually diverge” to violent levels. Despite concerns about the outcome and safety of the reaction, when the cadmium strips were re-inserted, the intensity dropped to a safe level. Fermi’s calculations had been correct, and it had been executed successfully.
Fermi would soon be moved to Los Alamos, New Mexico to join the main branch of the highly classified Manhattan Project, which sought to rapidly produce atomic weapons in the United States.
The Post-War Era and Scientific Advancements
In 1945, the Manhattan Project culminated in the construction of the atomic bomb, the use of which on the cities of Hiroshima and Nagasaki marked the end of World War II. Notably, the Nagasaki bomb used plutonium, researched by the Met Lab, instead of uranium.
Around the same time, the Met Lab officially became affiliated with the University and was converted into Argonne National Laboratory, a prominent physics research institution to this day.
UChicago funds about 50 million dollars per year of Argonne’s research in both physical and life sciences, particularly nuclear reactor experiments.
Argonne has also become a center for scientific supercomputing; it currently owns and operates Aurora, one of the fastest supercomputers in the world. According to Argonne scientists, Aurora can perform more than one quintillion calculations every second. Argonne has said that its high-performance computers represent a significant streamlining of the research process relative to Fermi’s age, automating calculations that were once done manually.
In 1967, the Fermi National Accelerator Laboratory, commonly known as Fermilab, began operations. The UChicago-affiliated lab has been churning out advancements in atomic physics since its foundation. Fermilab scientists have directly discovered two kinds of subatomic particles, the top quark and bottom quark, and verified the existence of a third, the tau neutrino—all of which are essential for understanding the fundamentals of the universe.
In addition to Argonne and Fermilab’s accomplishments, two central discoveries about the behavior of particulars on a small scale—quantum superposition, where things exist in multiple states at the same time, and entanglement, where things that should be completely independent actually affect each other—laid the groundwork for new derivative sciences.
One of these sciences was molecular engineering, the focus of the only engineering major offered at Uchicago.
New Leaders: PME and the Chicago Quantum Exchange
The Pritzker School of Molecular Engineering (PME) was founded in 2011 and works closely with companies such as IBM and partners with Argonne and Fermilab. It has grown into “the core of quantum, on campus and in the region,” PME’s dean, Nadya Mason, told the *Maroon*.
PME, like Argonne and Fermilab, champions a blend of theoretical training and experimental experience. It offers three tracks for its undergraduate students to pursue, one of which focuses on quantum engineering.
In molecular engineering, theory and practice feed into each other, says Doğa Kürkçüoğlu, a theoretical physicist at the Fermilab Quantum Institute. “Trying to determine whether theory leads to experiment or experiments allow us to advance theory is like trying to determine whether the chicken or the egg came first,” he told the *Maroon*. Indeed, researchers at PME have challenged the strict separation between a theoretical and empirical approach, opting to increase interactions between theorists and experimentalists.
Rohan Mehta (S.B. ’25), a recent quantum engineering graduate from PME, agreed, dubbing this phenomenon an “experimental-theoretical integration.”
One of the main disciplines making use of quantum mechanics is quantum computing. “In our classical computers, we use binary [i.e., bits]—0 or 1—because we’re very used to, in normal physics, either having something or not having it,” Mehta explained. “A switch can be on or off.” That binary structure does not hold in quantum physics.
“We don’t necessarily have a particle that’s here or there. But we have some particle that, in some very complicated way, is kind of both, and behaves in a completely different manner than what we’re used to.”
Quantum computers take advantage of fundamental units called quantum bits, or qubits. These derive their efficiency from the laws of quantum mechanics; as Mehta puts it, “when you have different physics, you can encode different kinds of information. And that allows you to do new kinds of computing.” The exploitation of quantum mechanics’ inherently probabilistic, uncertain nature is what makes quantum computing so powerful.
Many of the other quantum derivative sciences are also directly applicable to real-world scenarios. For example, entangled particles can be used to generate quantum communication networks that can transmit information rapidly and securely.
“We have one of the world’s largest, longest quantum networks that has entangled particles going over long distances from here to [the University of Illinois Urbana-Champaign] and back again. And so we’ve been exploring what we can do with these networks,” Mason said. In this sense, PME has helped UChicago to enact its quantum discoveries in various contexts and to establish collaborations with other institutions in the Chicago area.
In 2017, UChicago, Argonne, Fermilab, and UIUC founded the Chicago Quantum Exchange (CQE), based at UChicago’s PME.
The CQE hosts regular symposiums at its partner institutions, builds physical quantum communication networks, and publishes reports on the progress of quantum research in the Chicago area.
Mason describes the CQE as “the basis for Chicago being the world’s center for quantum.” From chemists to mathematicians to computer scientists to engineers, Chicago-area researchers working in the quantum domain come together to advance quantum research, prepare the next generation of quantum leaders, and fuel the quantum economy.
Industrialization and the Scaling Problem
In the wake of these academic developments, the baton has—at least partially—been passed to industrial players who seek to implement quantum discoveries in physical computers and hardware.
Companies like IBM and Google, along with quantum-specific corporations, such as D-Wave Quantum, Quantinuum, and Infleqtion, form the backbone of the quantum economy, which encompasses the investments, jobs, infrastructure, and commercialization of everything quantum.
The Chicago area is a nexus of growth in quantum technology. In 2024, the Boston Consulting Group projected that quantum technology providers in Illinois, Indiana, and Wisconsin alone could generate $80 billion in economic value—roughly 30 percent of the global figure for the industry—by 2035. Additionally, Palo Alto startup PsiQuantum has selected a site on the South Side, just five miles from UChicago, as the location for its industrial-sized quantum computing campus, to be named the Illinois Quantum and Microelectronics Park.
However, one central problem with modern quantum computing remains. Qubits, unlike bits, are prone to strange forms of perturbation including decoherence, where temperature fluctuations cause qubits to lose their functionality. They can also generate noise due to their sensitivity to random small particles.
The demand for improved quantum hardware, Mason said, is immediate. “We’re not always the most efficient at using the technologies that we have, and as technologies get better, sometimes we run into pretty strict hardware limits,” Mason said. Many major companies are developing next-generation quantum computers, cryogenic technologies to stabilize qubits, and more efficient qubits themselves.
“All the world’s current computers operating together can’t do what a one-million-qubit quantum computer will be able to do,” Microsoft wrote in an official statement. This is just one example of the incredible potential of the intersection between quantum computing and modern industrial technology.
Current State of Quantum and Next Steps for Chicago
UChicago continues to be involved in the development of quantum computing.
The Chicago Quantum Exchange, in its annual report, characterized 2024 as “a year of unparalleled progress” for the Chicago quantum community: a UIUC-led experiment tested quantum communication technology in outer space; PME scientists leveraged properties of diamonds to attain more precise measurement technologies for quantum systems; and a Fermilab experiment succeeded in lengthening qubit lifetimes using a special class of qubits called superconducting qubits. UChicago is also collaborating with the State of Illinois to create a new quantum algorithm center, powered by IBM’s advanced quantum computers.
Researchers are still developing ways to tackle the biggest problems slowing progress in quantum computing, such as decoherence and noise. Mehta is currently conducting theoretical research in this field, known as quantum error correction.
“Error correction is really one of those things that we need at scale,” Mehta said. Large portions of quantum computing’s usefulness, especially for industrial-level applications, depend on error correction. Mehta says he is “quite optimistic” about the field’s potential, adding, “[T]he theory is very strong, and I think now it’s about integrating it into devices.”
With the International Year of Quantum just passed, scientists and engineers are working relentlessly toward realizing the first fully functional quantum computer. Kürkçüoğlu predicts that this advance will “completely revolutionize the quantum and larger scientific landscape.”
Chicago, equipped with the world’s premier experimental and computational resources, a constellation of dedicated scientists, and a major quantum science proponent in the form of Governor J. B. Pritzker—who has secured billions of dollars in quantum computing investments—is poised to expand its role as the forerunning intellectual and industrial center of quantum science.
As quantum science progresses and researchers improve the theoretical, industrial, and physical infrastructure supporting it, more major breakthroughs are set to arrive.
“Science is a combination of great ideas and tools that allow you to implement those great ideas,” Mason said, expressing excitement about the future. “It benefits all of us to have quantum be successful in Chicago, and with the significant support we’ve received [for] the partnerships across our universities and labs, I think we’re going to do it.”
