Quantum research in UChicago lab could help prevent hacking and connect future supercomputer networks
The modest decor of the Equipment Closet LL211A belies the importance of a cutting-edge project in one of the world’s hottest technology competitions. The United States, China and others are working to harness the exotic properties of quantum particles to process information in powerful new ways—a technology that could bring significant economic and national security benefits to the nation that dominates it.
Quantum research is so important to the future of the internet that it is attracting new federal funding, including the recently passed Chip and Science Act. That’s because, if it succeeds, a quantum internet could protect financial transactions and healthcare data, prevent identity theft and stop the trail of hackers from hostile countries.
Just last week, three physicists shared the Nobel Prize for quantum research that could help pave the way for the future of the internet.
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There are still many hurdles to overcome before quantum research can be widely used. But banks, healthcare companies and others are starting to experiment with quantum internets. Some industries are also tinkering with early quantum computers to see if they can finally solve problems that current computers cannot, such as discovering new drugs for intractable diseases.
Grant Smith, a graduate student in the University of Chicago’s quantum research team, said it’s too early to imagine all the potential applications.
“When people first set up the basic internet connecting research-grade computers and universities and national labs, they couldn’t predict e-commerce,” he said during a recent tour of university labs.
The study of quantum physics began in the early 20th century, when scientists discovered that the tiniest objects in the universe—atoms and subatomic particles—behaved differently than matter in the large-scale world, such as in multiple places at once.
Known as the first quantum revolution, these discoveries gave rise to new technologies such as lasers and atomic clocks. But research now is bringing scientists one step closer to harnessing more of the special forces of the quantum world. David Oshalom, a professor at the Pritzker School of Molecular Engineering at the University of Chicago and head of the quantum team, called this the second quantum revolution.
The field, he said, is “trying to engineer the most fundamental ways in which nature behaves towards our world and use those behaviors for new technologies and applications”.
Existing computer and communication networks store, process and transmit information by breaking it down into long streams of bits, usually electrical or optical pulses representing zeros or ones.
Quantum particles, also known as qubits or qubits, can exist as both zeros and ones at the same time, or anywhere in between, a flexibility called “superposition” that allows them to form new way of processing information. Some physicists liken them to spinning coins that are both heads and tails.
Qubits can also exhibit “entanglement,” in which two or more particles are inextricably connected to each other and mirror each other precisely, even at great physical distances. Albert Einstein called this “spooky action at a distance”.
The closet hardware is connected to a 124-mile fiber optic network that connects from the university campus on Chicago’s South Side to two federally funded labs in the western suburbs — Argonne National Laboratory and Fermi National Accelerator Laboratory.
The team is using photons—quantum particles of light—to send encryption keys across the network to see how they travel through the fibers beneath highways, bridges and toll booths. Quantum particles are very fragile and have a tendency to malfunction under the slightest disturbance, such as vibration or temperature changes, so sending them over long distances in the real world is tricky.
In the university’s basement closet, a piece of hardware made by Japan’s Toshiba fired a pair of entangled photons and sent one of each pair over a network to Argonne, in Lemont, Illinois, 30 miles away. An encryption key is encoded on a string of photon pairs.
Because the pair is entangled, they are perfectly synchronized with each other. “In a sense, you can think of them as a piece of information,” Awschalom said.
When the traveling photons reach Argonne, scientists there measure them and extract the key.
Anyone trying to hack into the network to intercept the keys will fail, Awschalom said, because the laws of quantum mechanics state that any attempt to observe a particle in a quantum state automatically changes the particle and destroys the information being transmitted. It also alerts senders and receivers about attempted eavesdropping.
That’s one reason scientists believe the technology is so promising.
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“There were huge technical difficulties to overcome, but you could argue that this could become as important as the technological revolution of the 20th century, which gave us lasers, transistors, and atomic clocks, and therefore GPS and the Internet,” Stey said. Steven Girvin, professor of physics at Yale University, talks about the latest discoveries in quantum technology.
In a lab next to the closet, Awschalom and his colleagues are trying to develop new devices to help photons carry information over greater distances. The room was packed with photos of multimillion-dollar lab equipment, lasers and Thomas Tank engines as one of the instruments kept crunching. “I think, it’s for comedic value,” said graduate student Cyrus Zelliden.
One problem they were trying to solve: When tiny particles of light travel through the network’s glass fibers, defects in the glass cause the light to decay over a certain distance. So researchers are trying to develop devices that can capture and store information as light particles travel, and then send it again with new particles—like the Photon Pony Express.
To avoid damaging the surface, Zeledon, wearing purple latex gloves, held up a tiny circuit board containing two silicon carbide chips that he and his colleagues were testing as a device to store and control information from qubits. Later in the day, Zeledon plans to cool the chips to ultra-cold temperatures and examine them under a microscope, looking for qubits he’s implanted in the chips, which he can then manipulate with microwaves to exchange information with photons.
On a recent morning, on the other end of the network, Argonne scientist Joe Heremans, a former student of Awschalom, apologized for the loud rattles that echoed around his lab. Where is the picture of Thomas, his tank engine? “We’re trying to be a little bit more professional here,” he joked.
Hermans and his colleagues are also trying to develop new devices and materials to help photons transport quantum information over greater distances. Synthetic diamond is a promising material, he said, referring to a reactor that grows diamonds at the rate of nanoglaciers per hour.
Federal funding from the National Quantum Initiative Act, passed by Congress and signed by President Donald Trump in 2018, recently helped the lab purchase a second reactor that will grow diamonds faster. The Chip and Science Act, signed by President Biden in August, is providing additional support for research and development to support quantum research.
In one corner of his lab, Hermans points to a Toshiba machine identical to the one at the University of Chicago. From there, a clutter of colored wires carried the signal to the network, which after leaving the lab made a short loop under nearby IKEA and Buffalo Wild Wings, before firing at the university and Fermilab in either direction.
Scientists are experimenting with similar test beds in Boston, New York, Maryland and Arizona. Experimental networks also exist in the Netherlands, Germany, Switzerland and China.
The goal is to one day connect all of these testbeds via fiber-optic and satellite links to an emerging quantum internet that spans the U.S. and the world. If the network grows, it could ideally be used not only to send encrypted information, but also to connect quantum computers to increase their processing power, as the cloud does for current computers.
“The idea of a quantum internet is very much in the process of being born,” Smith said.