Researchers Reveal Key to Improving Quantum Internet Performance

Material scientists who study the efficiency of photons as carriers of information have developed a model that explains how the efficiency of those light particles changes at higher wavelengths. Their findings could have a major impact on the development of the most anticipated technological breakthrough: the quantum communication network.

Today’s fiber-optics are able to transmit photons (individual light particles) with minimal loss at the wavelengths used for telecommunications. In a quantum system, photons act like bits in a classical computer.

What does light have to do with the internet?

The quantum internet does not yet exist, but it is expected to resemble a network of quantum computers that transmit information as quantum bits, or qubits. These qubits are particles in a quantum state, which allows them to contain more information than the value 0 or 1, just like the bits of a classical computer.

As previously reported by Gizmodo, the quantum internet won’t work much differently than the internet you access through your current browser. But putative technology should allow information to be encrypted with greater security than information on the Internet today, and it will use the laws of quantum mechanics to achieve that goal.

What did the researchers find?

In their new paper—published last month in APL Pictures-physicists present a model that explains the role of electron-photon coupling in a type of single-photon emitter. Their work suggests ways to improve the efficiency of these photon emitters.

“Atoms are constantly vibrating, and that vibration can release energy from a light emitter,” said Chris Van de Walle, a materials scientist at UC Santa Barbara and an author of the paper, in a university release. “As a result, instead of emitting a photon, the defect may cause the atoms to vibrate, reducing the efficiency of light emission.”

The team noted that they do not believe the “Goldilocks” single-photon emitter has yet been found, but they believe it will have a transmission capacity of about 1.5 electronvolts.

“Because of the very high efficiency that can be obtained at short wavelengths, we suggest that if telecom frequencies are needed to be transmitted in optical fibers, quantum frequency conversion should be considered alongside direct generation,” the team wrote.

“Careful selection of host materials, and atomic-level engineering of vibrational structures are two promising ways to overcome low efficiency,” said Mark Turiansky, a researcher at UC Santa Barbara and the project’s lead researcher, in the same release.

Another way to deal with the low efficiency, the team wrote, is to combine a photonic cavity, a device that can be used to “open frequency bands where it is not allowed to distribute electromagnetic waves regardless of the direction of propagation in space,” as another team put it in IEEE.

We are a long way from the quantum internet, but its foundation has been a project of the last decade. In early 2020, the Department of Energy released its blueprint for “Building a Global Quantum Internet,” which, apart from secure quantum communications, could boost quantum computing and help existing sensor networks.

Don’t hold your breath waiting for the quantum future—it will be blue—but know that fundamental research in materials and computer science today is laying the foundation for a new kind of communication.