2022 Nobel Prize in Physics awarded for quantum entanglement experiments

Today’s Nobel Prize in Physics award brings attention to the new field of quantum information science. Clauser, Aspect, and Zellinger’s work focused on quantum entanglement—the concept that two objects can be linked at a distance in a way that’s impossible to duplicate with ordinary “classical” physics. Dismissed by none other than Albert Einstein as “spooky action at a distance,” quantum entanglement refers to the ability of elementary particles like photons and atoms to maintain synchronized correlation of their physical properties such as polarization and spin even when separated by substantial distances. 

The work of this year’s Nobel Laureates not only proved that quantum theory reflected the real world (and, incidentally, that Albert Einstein was wrong), but they created an entirely new way to look at information processing. Quantum information science uses entangled bits to compute, sense, and transmit information more efficiently—which could be encrypted financial transactions, or astronomical observations, or medical images used in diagnosing cancer. (Sadly, and contrary to popular impression, quantum entanglement does not enable faster-than-light communication, nor will we be stepping into Star Trek transporters anytime soon.)

Quantum computers exploit the quantum-mechanical nature of photons, electrons, or atoms to process information that can vastly outperform today’s computers on certain tasks. These tasks include simulating complex molecules enabling drug discovery, recognizing patterns in large data sets, certain planning/scheduling challenges… and breaking most currently-available forms of encryption. Quantum sensors use exquisitely calibrated devices to sense tiny changes in signals with much finer resolution than can be achieved with classical devices. Such signals may include light collected by a microscope examining biological tissue, the magnetic field created by neuronal activity in a human brain, or photons from distant galaxies collected by a telescope. Quantum networks — the goal of the Center for Quantum Networks — endeavor to connect large combinations of quantum computers and quantum sensors using communication channels that can transmit quantum bits, in a robust way over long distances. The quantum information will be encoded into photons and transmitted over optical fibers or through free space — either over centimeters (inside a computer), meters (inside a data center), kilometers (a metro area), or thousands of kilometers (continental or intercontinental). 

Quantum information science is a two-edged sword. On one hand, quantum computers raise the possibility of quickly and economically breaking most common encryption mechanisms, which underpin everything from banking to medical records to navigation to cryptocurrencies. On the other hand, quantum networks promise an inherently-secure communications mechanism that will allow the safe transmission of information, even when attacked by adversaries with quantum computers. Networks based on quantum entanglement will initially be used for high-value information security applications. But as the technology becomes more cost effective, the applications will spread to a variety of uses, including improved navigation, long-baseline astronomy, medical imaging, and distributed quantum computation. Eventually, a widespread network of quantum computers, quantum sensors, and quantum networking devices acting together will enable applications which are difficult to imagine today. 

Imagine observing the birth of ARPANET, the predecessor of today’s Internet, in 1969. It would be relatively straightforward to predict email. Only a deep technical visionary in 1969 could have predicted the World Wide Web. And only a crazy science fiction author could have predicted elections turning on Twitter postings, or teenagers pursuing TikTok fads on a video platform that they carried in their pockets!

So, yes, there will be new products in banking, manufacturing, communications, medicine, and more. We don’t yet know what all of them will be. But we do know that — ever since the invention of the telegraph — every time humanity gets a new computing or networking capability, brilliant entrepreneurs turn those into products and services that change our lives. Of course, just like with the telegraph, telephone, or the Internet, there will be complex social, political, and legal consequences of quantum information science. At the Center for Quantum Networks, we have elevated these challenges to be on a par with our fundamental research in physics, chemistry, mathematics, and engineering. We’ve recruited legal scholars, historians, policy experts, and more to help analyze the potential impact of quantum information science and to try and mitigate some of the risks before they occur.

Although there is still important work to be done on both the theory and the practice of quantum information science, it is important to note that this year’s Nobel Prize was awarded to experimentalists, not theorists. Quantum information science is real. Quantum computers (and the software tools to program them) already exist, being built by huge companies like Google and IBM as well as a bewildering array of startups. Venture capital is flowing into the sector at a rapid pace, and new Federal programs should provide additional resources to commercialize the technology. 

It is still very early in the world of developing products and services based on quantum entanglement. Many of the devices only operate at super cold temperatures, a fraction of a degree above absolute zero, inside complex and finicky laboratory installations. One of the goals of the Center for Quantum Networks is to migrate those capabilities into computer chips that can operate at much higher temperatures—either liquid helium (like your hospital’s MRI machine) or even liquid nitrogen (which high school kids use for chemistry demonstrations, and to make instant ice cream). 

Quantum-enhanced sensors for real-world applications such as imaging, spectroscopy, magnetometry, and navigation are likely to come to market in this decade. Developing more robust commercial-grade long-distance quantum networks will occupy scientists and engineers well into the next decade. Sensor networks that benefit from distributed entanglement will be deployed over those robust quantum networks. The highest value applications will emerge first, in military and financial transactions. Consumer-oriented applications will come later. That’s the same evolutionary path we saw with the Internet, and we expect history will repeat itself… but maybe a little faster this time!

The NSF Center for Quantum Networks (CQN — https://cqn-erc.org/), headquartered at the University of Arizona in Tucson, is a 10-year $51 million investment of taxpayer dollars, involving MIT, Harvard, Yale, the University of Massachusetts at Amherst, the University of Oregon, Northern Arizona University, the University of Chicago, Howard University, Brigham Young, and a consortium of 15+ industry partners including Cisco, Corning, Juniper, and L3Harris. CQN is developing the entire technology stack to upgrade the Internet to reliably carry quantum data across the globe. CQN devices and networks will distribute entanglement among distant parties at high rates and high fidelities, to serve diverse applications across many user groups simultaneously, while meeting the dynamic application-driven demands of the quality-of-service of this new service of quantum communication. CQN aims to lay the foundations for a socially responsible quantum Internet, built and maintained by a diverse workforce of quantum scientists, engineers, and technicians. We believe that the quantum Internet will spur new technology industries and a competitive marketplace of quantum service providers and application developers.