Hannes Bernien awarded the 2023 Klung Wilhelmy Science Prize for pioneering quantum work
Each year, the Klung Wilhelmy Science Prize in Physics is awarded to Germany’s most promising early career physicist. Since 1979, only 21 researchers have achieved the honor, a list that includes four physicists who went on to win Nobel Prizes.
As of today, that list also includes Asst. Prof. Hannes Bernien of the University of Chicago’s Pritzker School of Molecular Engineering (PME). Bernien has earned the prize for his pioneering early studies on defect centers in diamonds and work he is currently pursuing at PME to develop quantum technology platforms based on Rydberg atoms, literally building quantum computers from the atom up.
“What is special in this technique that we developed is that you can assemble large quantum systems atom by atom,” Bernien said. “You literally pick up single atoms using focused laser beams and we can put them wherever we want them.”
Even more compelling is when Bernien makes the atoms interact with each other.
By switching the laser back on to excite the atoms, Bernien is able to generate shared quantum states, entangling the precisely placed atoms. This has massive implications for how researchers can build quantum computers.
“You can really think of each individual atom as a qubit, the building blocks of quantum computers,” Bernien said. “This is a great way of assembling a quantum processor with hundreds or maybe thousands of qubits.”
Spooky action at a very, very large distance
Diamonds with defects are another exciting area of quantum study, allowing researchers one of the few opportunities to explore quantum phenomena at room temperature.
Bernien helped advance this field during his PhD work, where his thesis used demonstrated a protocol to entangle two spins in two separate diamonds. Entanglement linked the two physically unconnected spins so that one cannot be described without the other. Einstein famously called quantum entanglement “spooky action at a distance.” Bernien stretched that distance farther than any other researcher in history.
“During my PhD, we made an entangled state over 1.3 kilometers,” Bernien said. “This is part of the reason for the award.”
Entangling individual matter qubits at that distance allowed Bernien and his team to conduct the universe’s first loophole-free Bell test, proving that nature is essentially non-local. The 1.3-kilometer record was set in 2015, but still stands today. Bernien expects that his PME lab will soon produce even longer demonstrations.
Diamond defects that made that research possible are a hot topic in quantum research, generating worldwide attention.
“There is fantastic research going on here at PME in Alex High's lab, in David Awschalom's lab, in Peter Maurer's lab,” Bernien said. “These defect centers in diamonds are extremely versatile, presenting many new and exciting possibilities.”
Bernien also has incorporated diamond defect work into the Quantum Engineering Laboratory course he and PME Asst. Prof. Alex High designed for undergraduates. While Bernien’s PhD work used the diamonds for long-distance entanglement, the students use them to build their own quantum sensors, helping to make this groundbreaking field a regular part of the PME experience.
Building from the atom up
After joining the Pritzker School of Molecular Engineering in 2018, Bernien sought to build on his postdoctoral work, pioneering a technique that does not just place atoms, but make them dance.
“This enormous flexibility in building these systems and then controlling it atom by atom has triggered a lot of research groups to now also do this. There are worldwide about 200 research groups that have begun doing this, as well as companies,” Bernien said. “There are now about five startup companies that want to build quantum computers based on this work.”
