Quantum research at a University of Chicago lab could help prevent hacking and connect a future supercomputer network
The Equipment Closet LL211A’s modest trappings belie the importance of a project at the forefront of one of the world’s hottest technology competitions. The United States, China and others are racing to harness the bizarre properties of quantum particles to process information in powerful new ways, a technology that could confer major national security and economic benefits on the countries that dominate it.
Quantum research is so important to the future of the internet that it is attracting new federal funding, even from recently adopted ones Chip law and science. That’s because, if it works, the quantum internet could safeguard financial transactions and health records, prevent identity theft, and stop hostile state hackers in their tracks.
Just last week, three physicists shared the Nobel Prize for Quantum Research who helped pave the way for this future Internet.
Quantum research still has many hurdles to overcome before it reaches widespread use. But banks, healthcare companies and others are starting to experiment with the quantum internet. Some industries are too tinker with early-stage quantum computers to see if they could eventually solve problems that current computers can’t, like discovering new drugs to cure incurable diseases.
Grant Smith, a graduate student on the University of Chicago’s quantum research team, said it’s too early to imagine all the potential applications.
“When people first created the rudimentary Internet networks connecting research-level computers, universities and national laboratories, they could not have foreseen e-commerce,” he said during a recent tour of the university’s laboratories.
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 in different ways than matter in the large-scale world, such as appearing to be in multiple places at the same time.
Those discoveries, called the first quantum revolution, led to new technologies like lasers and the atomic clock. But research is now bringing scientists closer to harnessing more powers peculiar to 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 is “trying to engineer how nature behaves at its most fundamental level in our world and exploit these behaviors for new technologies and applications,” he said.
Existing computers and communications networks store, process, and transmit information by breaking it down into long streams of bits, which are typically electrical or optical pulses that represent a zero or a one.
Quantum particles, also known as quantum bits, or qubits, they can exist as zeros and ones at the same time, or anywhere in between, a flexibility known as “overlap” that allows them to process information in new ways. Some physicists liken them to a spinning coin that is simultaneously in a state of heads and tails.
Quantum bits can also exhibit “weaving”, where two or more particles are inextricably linked and exactly mirror each other, even when separated by a great physical distance. Albert Einstein called this “spooky action at a distance.”
The cabinet hardware connects to a 124-mile fiber-optic network that runs from the university campus on Chicago’s South Side to two federally funded laboratories in the western suburbs that are collaborating on research: Argonne National Laboratory and the Fermi National Accelerator Laboratory.
The team is using photons, which are quantum particles of light, to send encryption keys across the network, to see how well they travel through fibers as they pass under highways, bridges and toll booths. Quantum particles are extremely delicate and have a propensity to malfunction at the slightest disturbance, such as a vibration or temperature change, so sending them long distances in the real world is tricky.
In the university basement closet, a piece of hardware built by the Japanese company Toshiba emits pairs of entangled photons and sends one from each pair across the network to Argonne, which is 30 miles away, in Lemont, Illinois. An encryption key is encoded on a string of photon pairs.
Because the pairs are intertwined, they are completely in sync with each other. “In a way, you can see them as one piece of information,” Awschalom said.
When the traveling photons reach Argonne, scientists measure them and extract the key.
Anyone attempting to hack into the network to intercept the key will fail, Awschalom said, because the laws of quantum mechanics state that any attempt to observe particles in a quantum state automatically alters the particles and destroys transmitted information. He also notifies the sender and recipient of the interception attempt.
This is one reason why scientists believe the technology holds such promise.
“There are huge technical hurdles to overcome, but it could be argued that this could become as important as the technological revolution of the 20th century that gave us the laser, the transistor and the atomic clock and, hence, GPS and the Internet,” Steven Girvin, a physics professor at Yale, said of the recent breakthroughs in quantum technology.
In a lab near the cabinet, Awschalom and his colleagues are attempting to develop new devices that will help photons carry information over greater distances. The room is a cramped tangle of million-dollar lab equipment, lasers, and a picture of Thomas the Tank Engine, because one of the instruments makes a constant popping noise. “I guess it’s for, like, comedic value,” graduate student Cyrus Zeledon said.
One problem they’re trying to solve: As tiny particles of light travel through the glass fibers of the mesh, imperfections in the glass cause the light to dim after a certain distance. So researchers are attempting to develop devices that can capture and store information from light particles as they travel, and then send the information back with a new particle, like a photonic Pony Express.
Wearing purple latex gloves to avoid damaging the surface, Zeledon has been holding up a tiny circuit board containing two silicon carbide chips that he and his colleagues are testing as a device for storing and controlling information from quantum bits. Later that day, Zeledon was planning to cool the chips to extremely low temperatures and examine them under a microscope, looking for quantum bits he had implanted into the chips which he could then manipulate with microwaves to exchange information with photons.
Across the net, one recent morning, Argonne scientist Joe Heremans, who was formerly an Awschalom student, apologized for the loud noise that was also echoing in his lab. Where was his picture of Thomas the Tank Engine? “Let’s be a little more professional here,” he joked.
Heremans and his colleagues are also trying to develop new devices and materials to help photons carry quantum information over greater distances. Synthetic diamonds are a promising material, he said, hinting at a reactor that was growing diamonds at the glacial rate of nanometers per hour.
Federal funding since National Quantum Initiative Act, approved 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 law and sciencesigned by President Biden in August, provides additional support for research and development that will strengthen 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 colored wires carries signals to and from the net, which, after leaving the lab, runs in a short loop under a nearby Ikea and Buffalo Wild Wings before shooting both ways toward the university and the 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 and satellite links, into a nascent quantum internet that spans the United States and eventually the world. As 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 today’s computers.
“The idea of a quantum internet is something that is in its infancy,” Smith said.