Chicago scientists are testing an unhackable quantum internet in their basement

The modest appearances of Equipment Closet LL211A belie the significance of a project at the forefront of one of the world’s hottest tech 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 confer major economic and national security benefits on countries that dominate it.

Quantum research is so important to the future of the internet that it is attracting new federal funding, including from the recently passed Chips and Science Act. Indeed, if it comes to fruition, the quantum internet could protect financial transactions and healthcare data, prevent identity theft, and stop hostile hackers in their tracks.

Last week, three physicists shared the Nobel Prize for quantum research that helped pave the way for this future Internet.

Answers to seven fundamental questions about quantum technology

Quantum research still has many hurdles to overcome before becoming mainstream. But banks, healthcare companies and others are starting to experiment with the quantum internet. Some industries are also tinkering with early quantum computers to see if they could possibly solve problems that current computers can’t, like discovering new pharmaceuticals to treat incurable diseases.

Grant Smith, a graduate student on the University of Chicago’s quantum research team, said it was too early to imagine all the potential applications.

“When people first created the rudimentary internets connecting research-grade computers, universities and national labs, they couldn’t have predicted e-commerce,” he said during a recent visit to 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 differently from matter in the world on a large scale, for example by appearing to be in several places at the same time. .

These discoveries, called the first quantum revolution, led to new technologies such as lasers and the atomic clock. But research is now bringing scientists closer to harnessing more of the special powers of the quantum world. David Awschalom, a professor at the Pritzker School of Molecular Engineering at the University of Chicago and leader of the quantum team, calls this the second quantum revolution.

The field “tries to engineer how nature behaves at its most fundamental level in our world, and harness those behaviors for new technologies and applications,” he said.

Computers and existing communication networks store, process and transmit information by breaking it down into long streams of bits, which are usually electrical or optical pulses representing a zero or one.

Quantum particles, also known as quantum bits, or qubits, can exist as zeros and ones at the same time, or in any position in between, a flexibility called “superposition” that allows them to deal with information in new ways. Some physicists compare them to a rotating coin that is simultaneously in a toss-up state.

Quantum bits can also exhibit “entanglement”, where two or more particles are inextricably linked and mirror each other exactly, even when separated by a great physical distance. Albert Einstein called this “frightening action at a distance”.

The closet hardware connects to a 124-mile fiber optic network running from the university’s campus on the south side of Chicago to two federally-funded labs in the western suburbs that collaborate on research — Argonne National Laboratory and Fermi National Accelerator Laboratory.

The team uses photons – which are quantum particles of light – to send encryption keys through the network, to see how far they travel through the fibers that run under highways, bridges and toll booths. . Quantum particles are extremely delicate and tend to malfunction at the slightest disturbance, such as vibration or temperature change, so sending them real long distances is tricky.

In the university’s basement closet, hardware built by the Japanese company Toshiba emits pairs of entangled photons and sends one of each pair through the network to Argonne, which is 30 miles away in Lemont. , Ill. An encryption key is encoded on a string of photon pairs.

Because the pairs are entangled, they are perfectly synchronized with each other. “In a sense, you can think of them as one piece of information,” Awschalom said.

When the traveling photons reach the Argonne, the scientists measure them and extract the key.

Anyone who tries to hack into the network to intercept the key will fail, Awschalom said, because the laws of quantum mechanics say that any attempt to observe particles in a quantum state automatically alters the particles and destroys the information transmitted. It also alerts the sender and receiver of the eavesdropping attempt.

This is one of the reasons why scientists think the technology is so promising.

Amazon joins quantum computer race with new Caltech center

“There are enormous technical difficulties to overcome, but one could say that it could become as important as the technological revolution of the 20th century which gave us the laser, the transistor and the atomic clock and, consequently, the GPS and the Internet,” Steven Girvin, a physics professor at Yale, said of recent discoveries in quantum technology.

In a lab next to the closet, Awschalom and his colleagues are trying to develop new devices that will help photons carry information over greater distances. The room is a cramped tangle of millions of dollars worth of lab equipment, lasers, and a picture of Thomas the Tank Engine, as one of the instruments makes a constant hissing sound. “It’s for, I guess, comedic value,” said graduate student Cyrus Zeledon.

A problem they are trying to solve: when the tiny particles of light pass through the glass fibers of the grating, the imperfections in the glass cause the light to attenuate after a certain distance. Researchers are therefore trying 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 held up a tiny circuit board containing two silicon carbide chips that he and his colleagues are testing as a device to store and control information from quantum bits . Later that day, Zeledon planned to cool the chips to very 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 swap information with photons.

On the other end of the network, on a recent morning, Argonne scientist Joe Heremans, who had previously been Awschalom’s student, apologized for the loud hissing sound that also echoed around his lab. Where was his picture of Thomas the Tank Engine? “We try to be a bit 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, nodding to a reactor that was churning out diamonds at the glacial rate of nanometers 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 Chips and Science Act, signed by President Biden in August, provides 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 jumble of colored wires carry signals to and from the network, which, after leaving the lab, loops under a nearby Ikea and Buffalo Wild Wings before shooting back and forth to 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, to a nascent quantum internet spanning the United States and, eventually, the entire 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, much like the cloud does for today’s computers.

“The idea of ​​a quantum internet is something that is being born,” Smith said.