New $8 Million Grant to Fund Research in Quantum Communication

Prem Kumar's Center for Photonic Communication and Computing will lead the research

The McCormick School of Engineering at Northwestern University will be the lead agency among a group of universities and businesses that have received a four-year, $8 million grant to research advanced quantum communications.

With the funding researchers hope to take steps toward performing quantum communications – which involve transmitting information through qubits, such as photons – in the same reliable, fast manner that we perform classical communications.

Prem Kumar“We live in a world where we are always connected, where we can get any information we need when we want it,” said Prem Kumar, AT&T Professor of Information Technology, professor of electrical engineering and computer science, and director of the Center for Photonic Communication and Computing. “The goal is to have quantum communications at the same level, and we’re nowhere near that yet. We are working at the border of classical and quantum communications to find new ways to achieve that goal.”

The funding, granted through the Defense Advanced Research Project Agency’s Quiness program, will be spread among five universities and three industrial partners: University of California - Davis, University of Texas - Arlington, University of Calgary, and Montana State University; and industrial partners Raytheon BBN Technologies, Advanced Communication Sciences, and NuCrypt LLC.

Classical computing and communication works by processing "bits" that exist in two states, either one or zero. Quantum communication uses quantum bits, or qubits, which, in addition to being one or zero can also be in a "superposition," which is both one and zero simultaneously. This is possible because qubits are quantum units like atoms, ions, or photons that operate under the rules of quantum mechanics instead of classical mechanics. 

When harnessed, the "superposition" state can process significantly more information in a possibly much shorter time than classical communication processes, with a much higher level of security.

But conducting quantum communication on the current telecommunications infrastructure remains a challenge. While optical fiber cables used nowadays in classical communication can carry around 10 terabits of information per second across vast distances, that infrastructure can barely support 1 megabit per second over 100 kilometers using quantum communication techniques due to physical challenges that lie in the quantum realm. Quantum information is fragile and cannot be amplified with traditional means.

Kumar and his group plan to combine their research from the last two decades to find new approaches to these problems. One approach, quantum frequency conversion, by which the frequency of a light beam can be changed while preserving its quantum state, was developed in Kumar’s group two decades ago and was recently highlighted in Physics Today as groundbreaking work in the field. Kumar and his group also hope to build on work done at partner universities, including using atoms as quantum repeaters (similar to amplifiers) and creating pulses of light (arbitrary optical waveform generation) to move quantum information farther distances.

“The goal of this program is far-reaching,” Kumar said. “But we’re going to use every trick-of-the-trade that we’ve worked on over the years to make it happen.”