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Arts and Sciences co-investigators support project to create quantum bits with rare-earth ions

February 16, 2022

Arts and Sciences co-investigators support project to create quantum bits with rare-earth ions

Quantum bits inside of a quantum computer

Quantum information science (QIS) research isn’t new on Ohio State’s campus. However, a recent Catalyst Grant through the President's Research Excellence program to develop novel quantum bits for quantum networks could change everything for the university and the international QIS community.

Gregory Lafyatis

Gregory Lafyatis, an associate professor in the Department of Physics, expects that QIS will begin to have a significant role in transforming science and technology within the next several years. He describes QIS as having three distinct parts: sensing, communications and computing.

American theoretical physicist Richard Feynman invented quantum computing in the late 1970s, far before the research had any relevant applications. But like technologies we now think of as commonplace, such as lasers and magnetic resonance, no one realized the possibilities his work unlocked until decades after conception.

“The progress is always incremental, and there’s bound to be surprises on the way,” Lafyatis said.

Researchers dedicated to exploring QIS have already identified key ways it will benefit society. Quantum computers can assist in designing molecular vaccines and improving battery efficiency, among other uses. When scientists explore how to improve the material and biological components of a resource, they are essentially looking at its quantum mechanics.

Quantum computers are also far better at solving problems where parallelism is involved. For example, the “traveling salesman problem” is a famous hypothetical dilemma in STEM that asks to map out the best route a salesman can take when only provided ​​a list of cities and the distances between each pair of cities. Instead of examining each potential route one at a time, quantum computers produce all of the outcomes at once.

“The devil is in the details because you have to have good algorithms and you have to have good hardware that’s suited for what you’re doing,” Lafyatis said.

QIS research hasn’t quite caught up to QIS theory. Lafyatis and his collaborators aim to improve the hardware used in quantum communication and computing. Many co-investigators within the College of Arts and Sciences were brought together by principal investigator Ronald M. Reano, a professor in the Department of Electrical and Computer Engineering in the College of Engineering, to capture all possible angles of the project. In October 2021, the team received a Catalyst grant from the Ohio State President’s Research Excellence (PRE) program, which supports cross- and interdisciplinary teams pursuing large-scale, high-impact research that addresses challenges of national and international societal importance, for the proposal “Creating quantum bits based on rare-earth ions for quantum networking.”

Lafyatis appreciated Ohio State’s willingness to take a chance on their research project because it can be difficult to secure funding from scientific agencies when there isn’t “proof of principle” yet.

This research could revolutionize QIS because the ability to make quantum bits (qubits) more quickly and more efficiently will lead to further advancements in the field. By using lasers at a 1550 nanometer wavelength to penetrate atoms of erbium, a rare-earth element that has outer electrons shielding the inner workings from external influences, communication between the atoms is possible. The researchers will make a very diluted vapor of erbium atoms that will be placed on a surface of hexagonal boron nitride (HBN) for observation. Studying how these atoms interact with the surface will indicate whether erbium is a good candidate for qubits, or if the HBN causes too much disturbance.

“The long-term vision is you put 1 million of these atoms down on a surface of HBN, you move them around, and then that's your quantum computer,” Lafyatis said. “That’s not going to happen tomorrow. If it happens in the next 10 to 15 years, we’ll be famous.”

Each person plays a fundamental role in the research project contributing specialized expertise in the fields of electrical engineering, physics and chemistry, in addition to scientific resources and technology from across departments.

“The team will be investigating the creation of quantum bits from fundamental principles involving quantum theory, spectroscopy and integrated waveguides,” Reano discussed with the Department of Electrical and Computer Engineering.

Everyone involved has a distinct step in the research process that calls back to the initial research that made them ideal for the effort. Daniel Gauthier, professor of physics, and Lafyatis had been toying with the idea of using HBN as a surface for atoms over the last few years but only recently landed on erbium as the ideal atom after some trial and error. Around the same time, Ezekiel Johnston-Halperin and Roland Kawakami, professors of physics, had been growing and studying HBN and evaporating rare-earth atoms onto surfaces using epitaxial growth, respectively. 

It just so happens that Alexander Sokolov, an assistant professor in the Department of Chemistry and Biochemistry, is an expert on the electronic structure of metal atoms, including erbium, and could help these researchers forge ahead in the project with some foresight into the end results of these experiments. But in the end, the missing piece was Reano because of his experience making optical waveguides with materials, such as silicon and lithium niobate, and connecting them to optical fiber that would allow qubits and quantum computers to communicate with each other.

Apart from progressing this research into reality, Lafyatis is equally excited for their proposal to support and expand the QIS community within Ohio State. With collaborators across the university sharing innovative ideas, imagination is the limit. 

Having a collective hub so researchers are less isolated when working on QIS projects will not only benefit faculty members, but also attract more thought leaders for open discussions and potentially provide QIS course opportunities for students.

“Ohio State is really in a good position to push this,” Lafyatis said.

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