‘People Want to Help Us’: With Travel Grant, Ukrainian Student Attends March Meeting to Share Work on Qubits

Theoretical physicist Polina Kofman might be drawn to the “peculiar and exotic,” but some things she does the old-fashioned way.

“I prefer to write equations on paper, old style,” she says. For trickier work, she turns to Wolfram Mathematica or Python.

Lately, she’s been using these tools to study the peculiar and exotic world of qubits, the most basic units of information in a quantum computer. When experimenting with a qubit, a physicist is manipulating “a quantum two-level energy system” — in this case, “ground and excited,” she says. “It’s quite a hot topic right now.”

Kofman, whose research today focuses on the interaction of qubits with graphene, recently presented her work at the 2024 APS March Meeting in Minneapolis, Minnesota. Although she arrived from Portugal, Kofman is a Ukrainian graduate student, hoping to someday return home to receive her doctoral degree from Ukraine’s B. Verkin Institute for Low Temperature Physics and Engineering.

The institute is in Kharkiv, a city in northeastern Ukraine that became a major target during Russia’s 2022 invasion. Russian strikes remain a threat, displacing and upending life in a city whose prewar population numbered 1.5 million.

Until she can return to Ukraine, Kofman calls the University of Lisbon’s Instituto Superior Técnico home. To support her trip to Minneapolis, she received funding from the APS Distinguished Student Program for Ukraine. The program — supported by the Alfred P. Sloan Foundation — covers up to $2,000 in travel expenses to APS and other meetings for graduate students and postdocs impacted by Russia’s invasion. Recipients can also use the award to attend meetings virtually.

The meeting was “an important step in my career,” she says, and a great opportunity to connect with theoretical physicists tackling similar systems.

Kofman has been studying qubits for four years, starting in the last year of her bachelor’s program at V. N. Karazin Kharkiv National University in Ukraine. Since then, interest in quantum computing has skyrocketed, making her work particularly interesting, she says.

In Kofman’s theoretical work, she studies the interaction of a qubit with graphene. Graphene is a sheet of carbon atoms laid out in a honeycomb pattern, an arrangement that gives it a unique combination of mechanical, electrical, and thermal properties. The material’s inherently 2D nature makes it “an ideal material” for study relevant to quantum computing, she says.

Of the strange effects she’s found, one has captured her curiosity in recent months. In her work presented at the March Meeting, Kofman explored the behavior of a qubit-graphene system in an electric field defined using a quasi-static approximation — where changes in the field strength are applied so slowly that, at any given time, they can be considered constant.

Analyzing the electric field around the graphene, Kofman found that it might exhibit a transistor-like response under the right conditions. Ubiquitous in modern electronics, transistors are small, semiconducting ‘gates’ that regulate current flow or amplify signals. In Kofman’s case, the graphene affects the optical and electronic behavior of the system by, for example, increasing the localized strength of the electric field.

But there’s much more to explore with this system, she says. “I’m about half of the way.”

To advance her work, and in the hopes of eventually securing a faculty position in Ukraine, Kofman is excited about the research collaboration supplement — up to $5,000 in total — offered by the APS program. The supplement supports a research visit for an awardee, in addition to attending a scientific meeting. So after the March Meeting, Kofman headed to New Orleans to spend the remainder of March exploring the dynamics of multi-qubit quantum systems with Denys Bondar, a theoretical and computational physicist at Tulane University.

APS programs like this rely on sustained financial contributions from the community, including organizations like the Sloan Foundation, to support students like Kofman. “I’m thankful for this program, and that I am here,” she says.

Kofman knows that not every graduate student or postdoc in Ukraine has been able to find or take advantage of the opportunities she has had. But her story is important to share, “for Ukrainians to see they are not alone,” she says — that “people want to help us.”

Learn how you can support APS programs like the Distinguished Student-Ukraine Program and other global initiatives.