Bell Labs’ Michael Eggleston on Nokia’s research into topological quantum computing

For over a hundred years, the industrial research and development company Bell Labs has enjoyed a prestigious history. It developed solar cells, the Unix operating system and many other technologies that are now found in homes, offices and laboratories.

In 2016, Nokia acquired the telecommunications company Alcatel-Lucent, which owned Bell Labs, and the historic organization now acts as the research branch of Nokia. Its primary focus is on developing emerging technologies, defined as those at least five years away from commercialization, and providing technical advice to Nokia. Conversely, Nokia identifies challenges affecting business users, which determines the direction of research at Bell Labs.

Right now, one of the major projects at Bell Labs is its research into quantum computing, of ever more practical importance to businesses as we edge closer to ‘Q-Day’.

Using the properties of subatomic particles, quantum computers are able to process vast amounts of information in a short space of time. It is expected that quantum computers will be capable of solving problems that would take conventional ‘classical’ supercomputers many years to complete, if at all.

“My team is split into two main areas,” says Michael Eggleston, research group leader at Bell Labs and a PhD physicist specializing in semiconductor physics and quantum mechanics. Eggleston’s specialist focus is on optoelectronic devices – electronic devices that can control, generate or detect light – and it’s here that Bell Labs is aiming to carve a space for itself in quantum research.

“One is on computation, looking at new ways of computing, as computing is just a fundamental requirement for any sort of communication. Communication and computation have always advanced hand in hand and we often are limited by what we can compute, so we look at new ways of doing it. We also look at sensing; sensing the world, understanding things. It's how we understand the world and change it, so sensors are vital to a lot of what we do.”

Theories and practicalities

Quantum computing is still an emerging field, with quantum computers usually found only in research laboratories. Part of the challenge of creating and operating quantum computers is that they are extremely delicate technologies; they need to avoid decoherence, which is the loss of quantum information due to interference from the external environment.

If this problem can be circumvented, enterprises could unlock advanced new capabilities such as previously impossible optimization and simulation techniques. At the same time, security firms are racing to establish post-quantum cryptography and governments are racing to establish quantum computers before threat actors do.

Avoiding or mitigating decoherence can be achieved through a variety of extreme measures, such as cooling the system to near absolute zero. The lifespan of quantum bits (otherwise known as qubits) is also very short (typically less than a second), which can contribute to errors and computing failures.

As part of its research into quantum computing, Bell Labs decided to focus on topological quantum computing using anyons – a subatomic quasiparticle that is found in two-dimensional systems. Nokia’s topological quantum computer uses electromagnetic fields to maneuver charges around a supercooled electron liquid. The manipulation of charges acts as a switch between topological states in the qubits. The resulting quantum states can be locked in place for weeks at a time.

“The topological qubit is like a transistor; it's this tiny device that's highly stable and will allow us to do new things in quantum computing that these other architectures just could never get,” says Eggleston.

Nokia’s topological quantum computer is still experimental and only able to store a single qubit, which can be used to perform simple gate processes. Although it has not yet reached the stage of upgrading to multi-qubit system, as a proof of concept it demonstrates how a topological qubit provides inherent advantages compared to other forms of quantum computing.

Quantum computing is a developing field that faces significant challenges on the path towards commercial viability. Even then, quantum computers will only be useful for specific types of calculations and problem solving, such as simulation modelling and analyzing big data.

Last year, Microsoft announced its Majorana quantum chip, which Microsoft chairman and CEO Satya Nadella claims could deliver quantum computers with real-world applications in “years, not decades”.

It is worth noting that even though Microsoft also use topological qubits, their approach is quite different. “The key difference is that we use gallium arsenide, which is a naturally occurring material, just using natural processes, and you get these quantum states that are naturally occurring,” says Eggleston. “What [Microsoft] have done is they've engineered this new state using this combination of superconductors and semiconductors, so it's just kind of a completely different physical way of creating the same type of system.”

Microsoft isn’t alone in the field, of course. IBM is targeting ‘quantum advantage’ through advancements in its quantum computing hardware by the end of 2026, while Google is powering ahead with its own first-party quantum chip, Willow.

It’s clear that quantum computers will be the next major development in computing. While they’ll primarily be useful for highly complex problems, such as decryption and problems involving solutions for complex mathematical problems, they may also be applied to sector-specific drug discovery and financial portfolio optimization.

However, quantum computers will also have a significant impact in terms of how we transmit sensitive information. This is due to their ability to solve encryption that was previously thought to be unbreakable, as well as their ability to transmit information in a way that cannot be intercepted, without this being detectable by the communicating parties.

“We're heavily involved in post-quantum cryptography security solutions, whether it's math-based approaches or physics-based approaches, like quantum key distribution or physical layer key generation, both on the research side, and Nokia does also have this as part of their roadmap,” says Eggleston.

“When we look at network security, we think the best strategy is security in depth; not just relying on one protocol or methodology, but layering them in an intelligent way so that you can basically add on top those reinforcement layers.”

For the moment, much of Bell Labs’ research into quantum computers is focused on developing the stability and accuracy to enable systems capable of processing complex problems with a high degree of trust.