In Jeff Thompson’s lab, much power lies in a single atom.
Thompson, associate professor of electrical and computer engineering, engineers the quantum behaviors of individual atoms for use in emerging computing, communications, and sensing technologies. In September, the Breakthrough Foundation awarded Thompson and colleagues the New Horizons in Physics Prize for work controlling individual atoms for quantum computing and other uses.
In recent years, Thompson’s group has pioneered a new approach to storing and processing quantum information, which is based on isolating and manipulating individual ytterbium atoms. Ytterbium is slightly more complex than more commonly used atoms such as rubidium or cesium, but has a number of unique features that are advantageous for building large-scale quantum computers. In recent experimental papers, they demonstrated lifetimes for quantum states exceeding several seconds, as well as techniques for manipulating them that are robust against imperfections such as misalignment of laser beams.
Thompson likened the choice of atom to the choice of a multitool, “and this ytterbium is the bigger, fatter Swiss army knife.”
In one recent advance, published in Nature Communications, Thompson and collaborators showed how a new ytterbium qubit could dramatically improve a quantum computer’s tolerance for faults, a problem well understood in conventional computers but exceedingly difficult in quantum systems.
In their proposed solution, the team found that they could store data in ytterbium atoms while ensuring that most errors can be easily seen without disturbing the qubits, converting them into so-called “erasure errors.” The technique increases the acceptable error rate four-fold, from 1% to 4%, a practical level for quantum computers currently in development.
Thompson said the idea of engineering qubits such as ytterbium to have more favorable types of errors could be useful beyond his ytterbium atoms. Researchers working on entirely different approaches to quantum computing are also now exploring the idea.
At Princeton, Thompson said, cross-pollination of ideas is common and leads to new advances. His motivation to think about new approaches to error correction came from a Princeton colleague talking about similar challenges for different types of quantum computers. The emphasis at Princeton, Thompson said, is not so much on competition as a collective interest in what is possible.
“I think what is important and fairly unique about our community is that we all do different things but still talk with each other in depth about our work,” he said. “That is an investment that has paid dividends for all of us.”