Quantum research at a University of Chicago lab could help prevent hacking and connect a future web of supercomputers
The unassuming trappings of the LL211A equipment cabinet belies the importance of a project at the forefront of one of the world’s hottest technology competitions. The United States, China and others are vying to harness the bizarre properties of quantum particles to process information in powerful new ways – a technology that could bring major economic and national security benefits to the dominant countries.
Quantum research is so important to the future of the internet that it’s attracting new federal funding, including from the recently passed Chips and Science Act. Because if it works, the quantum internet could protect financial transactions and health data, prevent identity theft and stop enemy government hackers.
Just last week, three physicists shared the Nobel Prize for quantum research that helped pave the way for this future internet.
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Quantum research still has many obstacles to overcome before it can be widely applied. But banks, healthcare companies and others are starting to experiment with the quantum internet. Some industries are also tinkering with early-stage quantum computers to see if they could potentially solve problems current computers can’t, such as B. the discovery of new drugs to treat intractable diseases.
Grant Smith, a graduate student on the University of Chicago’s quantum research team, said it’s too early to envision all possible applications.
“When people first built the rudimentary Internets that connected research-level computers to universities and national labs, they could not have foreseen e-commerce,” he said during a recent tour of the university’s labs.
The study of quantum physics began in the early 20th century when scientists discovered that the smallest objects in the universe – atoms and subatomic particles – behave differently than matter in the big world, e.g. B. by appearing to be in several places at the same time.
Dubbed the first quantum revolution, these discoveries led to new technologies such as lasers and the atomic clock. But the research is now bringing scientists closer to harnessing more of the special powers of the quantum world. David Awschalom, a professor at the University of Chicago’s Pritzker School of Molecular Engineering and leader of the quantum team, calls this the second quantum revolution.
The field “attempts to engineer the way nature behaves at its most fundamental level for our world and to leverage that behavior for new technologies and applications,” he said.
Existing computers and communication networks store, process, and transmit information by breaking it down into long streams of bits, which are typically electrical or optical impulses representing a zero or one.
Quantum particles, also known as quantum bits or qubits, can exist simultaneously as zeros and ones or in any position in between, a flexibility known as “superposition” that allows them to process information in new ways. Some physicists liken it to a spinning coin that is in a heads and tails state at the same time.
Quantum bits can also exhibit “entanglement,” where two or more particles are inextricably linked and mirror each other exactly, even when separated by great physical distances. Albert Einstein called this “spooky action at a distance”.
The cabinet hardware is connected to a 124-mile fiber-optic network that runs from the university’s campus on Chicago’s South Side to two federally-funded labs in the western suburbs that are collaborating on the research — Argonne National Laboratory and Fermi National Accelerator Laboratory.
The team uses photons – which are quantum light particles – to send encryption keys through the network to see how well they travel through fibers that run under freeways, bridges and tollbooths. Quantum particles are extremely sensitive and prone to malfunction at the slightest perturbation, such as vibration or temperature change, making it difficult to send them over long distances in the real world.
In the university’s basement, hardware built by the Japanese company Toshiba emits entangled photons in pairs and sends one of each pair through the network to Argonne, located 30 miles away in Lemont, Illinois. An encryption key is a chain of photon pairs that encrypts.
Since the pairs are entangled, they are completely in sync with each other. “In a way, they can be viewed as a single piece of information,” Avshalom said.
When the traveling photons reach Argonne, scientists measure them there and extract the key.
Any attempt to hack into the network to intercept the key will fail, Avshalom said, because the laws of quantum mechanics dictate that any attempt to observe particles in a quantum state will automatically alter the particles and destroy the information being transmitted. It also warns the sender and the receiver about the eavesdropping attempt.
This is one of the reasons scientists believe the technology is so promising.
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“There are enormous technical difficulties to be overcome, but one could argue that this could become as important as the technical revolution of the 20th century.” A physics professor at Yale, on recent discoveries in quantum technology.
In a lab next to the closet, Avshalom and his colleagues are trying to develop new devices that will help photons carry information over longer distances. The room is a tight jumble of multi-million dollar lab equipment, lasers, and a photo of Thomas the Tank Engine, because one of the instruments makes a constant chug. “I guess it has comedic value,” said graduate student Cyrus Zeledon.
One problem they’re trying to solve is that as the tiny light particles travel through the network’s optical fibers, flaws in the glass cause the light to fade after a certain distance. The researchers are therefore trying to develop devices that could collect information from the light particles, store it and then forward it again with a fresh particle – like a photonic pony express.
Wearing purple latex gloves to avoid damaging the surface, Zeledon held up a tiny printed circuit board containing two silicon carbide chips, which he and his colleagues are testing as a device for storing and controlling information from quantum bits. Later that day, Zeledon planned to cool the chips to extremely low temperatures and examine them under a microscope to look for quantum bits he had implanted in the chips, which he could then manipulate with microwaves to exchange information with photons.
On the other end of the network, on a recent morning, Argonne scientist Joe Heremans, who was previously Avshalom’s student, apologized for the loud chug that was also echoing in his lab. Where was his picture of Thomas the Tank Engine? “We’re trying to be a little more professional here,” he joked.
Heremans and his colleagues are also trying to develop new devices and materials that will help photons carry quantum information over longer distances. Synthetic diamonds are a promising material, he said, nodding toward a reactor that was growing diamonds at the glacial pace of nanometers per hour.
Federal funds from the National Quantum Initiative Act, passed by Congress in 2018 and signed into law by President Donald Trump, recently helped the lab buy a second reactor that will grow diamonds faster. The Chips and Science Act, signed into law by President Biden in August, offers additional support for research and development that will bolster quantum efforts.
In a corner of his lab, Heremans pointed to a Toshiba machine identical to the one at the University of Chicago. From there, a tangle of multicolored wires carries signals to and from the network, which, after exiting the lab, makes a short loop under a nearby Ikea and Buffalo Wild Wings before shooting out in both directions to the university and Fermilab.
Scientists are experimenting with similar testbeds 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 into a fledgling quantum internet that will span the United States and eventually the globe. Ideally, as the network grows, it could be used not only to send encrypted information, but also to connect quantum computers to increase their processing power, just as the cloud does for current computers.
“The idea of a quantum internet is in the early stages,” Smith said.