Taking quantum circuits from a vague academic notion to the factory floor in just over 40 years might sound daunting — even impossible. But as Yale physicist Robert Schoelkopf explains, it all came down to small groups of researchers with a willingness to learn and the patience to keep “pulling on strings.”
“We’ve had an incredible time exploring this playground,” Schoelkopf, a Sterling Professor of Applied Physics in the Yale School of Engineering & Applied Science, told a standing-room-only Sloane Physics Lab audience during a lecture on the groundbreaking research that culminated in the 2025 Nobel Prize in physics.
“It’s been kind of an amazing year, hasn’t it?” he added.
That’s an understatement. Last fall, Michel Devoret, Yale’s F.W. Beinecke Professor Emeritus of Applied Physics and Physics, won the Nobel Prize in Physics for his mid-1980s work (with John Clarke of the University of California-Berkeley and John M. Martinis of the University of California-Santa Barbara) which showed for the first time that properties from the microscopic quantum realm could be seen in the observable, physical world.
The Nobel news arrived shortly before Connecticut Gov. Ned Lamont pledged a $121 million statewide investment in quantum technology that includes support for QuantumCT, a nonprofit organization co-led by the University of Connecticut (UConn) and Yale University, and the development of a first-of-its-kind quantum incubator in New Haven. Two months prior, QuantumCT was named one of 15 finalists for a National Science Foundation (NSF) grant administered through the Regional Innovation Engines program.
QuantumCT is a public-private initiative that focuses on quantum research, innovation, and workforce development in Connecticut — with plans to expand the state’s research capacity and apply cutting-edge quantum technologies to aerospace, defense, pharmaceuticals, and other pillars of the state’s economy.
Then last month, Quantum Circuits Inc., a Yale start-up company co-founded by Schoelkopf, Devoret, and Luigi Frunzio, a senior research scientist in applied physics at Yale Engineering, sold for $550 million to tech company D-Wave, with plans to more than double its New Haven workforce.
“Having a vibrant academic component that pairs with the industrial component is important,” Schoelkopf said. “I think we now have a good balance between the two.”
But it took time.
In his lecture on Feb. 16, Schoelkopf presented a sweeping overview of four decades of research, starting with British-American physicist Sir Anthony Leggett’s speculation in the early 1980s that superconductivity might provide a testing ground for reproducing quantum phenomena in a human-made device.
This idea would lead to Devoret, Martinis, and Clarke’s studies, working with an electrical circuit to demonstrate quantum “tunneling” — in which a particle can travel through a barrier — on a macroscopic scale.
By the early 2000s, there was a “toolbox” of materials — capacitors, inductors, Josephson junctions — for researchers to employ in the creation of artificial atoms, known as “qubits,” that would contain quantum information.
Yale would launch its own approach to the exploration of quantum computing, led by Schoelkopf, Devoret, Steven Girvin (Sterling Professor of Physics in the Faculty of Arts and Sciences and professor of applied physics at Yale Engineering), and others. Their work over more than two decades has created a new research field called circuit quantum electrodynamics (circuit QED), an approach to quantum computing that uses particles of microwave light in a superconducting microwave resonator.
Steven Girvin
“It’s a really nice story, right?” Schoelkopf said. “We didn’t know anything, exactly, about where this would go when we started. You just have to keep pulling on strings.”
More work remains, he said, as researchers work to develop robust error correction systems that can enable the creation of quantum computers — devices with the potential to do computations that standard computers cannot.
“The important thing is a willingness to learn,” he said. “You never know what the next thing is that you’ll need to know in order to be less confused.”
Schoelkopf added that Yale’s continued investment in quantum — including the construction of the Physical Sciences and Engineering Building on Upper Science Hill, and its commitment to human connections — will keep the university at the forefront of field.
“Our superpower is that we are extra collaborative and extra interactive,” he said.
