Physicist John Reppy wins Buckley Prize

John Reppy, John L. Wetherill Professor of Physics Emeritus within the College of Arts & Sciences, has obtained the 2026 Oliver E. Buckley Condensed Matter Physics Prize. The award, which acknowledges and encourages excellent theoretical or experimental contributions to condensed matter physics, consists of $20,000 and is awarded yearly. 

The award committee mentioned Reppy obtained the prize for his “groundbreaking experiments” with helium, uncovering the role of vortices in the superfluid phase transition in helium films and establishing “the significance of topological excitations in two-dimensions.”

Reppy was recognized along with David Bishop, Ph.D. ’78, for research they did on helium 50 years ago; two others were honored for more recent research on the topic.

“It is a superb honor and an entire shock,” mentioned Reppy. 

“The Buckley Prize, a major international honor in condensed matter physics, is a tremendous distinction for John Reppy and David Bishop, as well as for the department and for Cornell University,” Julia Thom-Levy, professor and chair of physics (A&S) mentioned. “Their work has influenced many branches of physics within our department and beyond, and we are very proud to count them among our colleagues.”

Reppy’s early collection of experimental and theoretical works laid the inspiration for what are in the present day referred to as topological part transitions, an essential space of physics that may reveal new courses of quantum matter and play a key position in quantum computing purposes and different applied sciences. 

“The experimental physics research they carried out at Cornell in the 1970’s has been foundational in our understanding of the types of order which can be found in nature. They were studying helium – the only substance which remains liquid down to absolute zero temperature,” mentioned Erich Mueller, professor of physics (A&S).

“This award shows how research can have amazing impact in ways that were unexpected when it was originally done,” mentioned Stephen Hilgartner, the Frederic J. Whiton Professor of Science & Technology Studies (A&S).

Reppy and Bishop measured the second of inertia of a helium-coated mylar sheet, which was wrapped right into a spiral. They discovered that the mechanism for superfluidity is completely different in skinny movies than in bulk fluids. Subsequently, David Nelson, Ph.D. ’74 and J. Michael Kosterlitz emphasised the connection between the Kosterlitz-Thouless (Ok-T) idea and the experimental outcomes of Reppy and Bishop which established that this novel superfluid state displays a sort of order now dubbed “topological.” 

As Reppy wrote in a memoir printed in Annual Review of Condensed Matter Physics in 2022, “As it turned out, this experiment was a realization of the Kosterlitz–Thouless (K-T) theory …The K-T transition was an early example of what is now known as a topological phase transition … In 2016, Kosterlitz, Thouless, and Haldane were awarded the Nobel Prize for their theoretical contributions to the theory of topological phase transitions, including the K-T transition in 4He films.”

Reppy obtained his B.A. in 1954 and his M.S. in 1956 from the University of Connecticut, and his Ph.D. in 1961 from Yale University. Before coming to Cornell in 1966 he was a physics professor at Yale University. He retired from Cornell in 2004 after 44 years within the physics division – then continued his analysis into helium for an additional ten years. He obtained over 50 years of analysis assist from the National Science Foundation. 

He is a fellow of the American Academy of Arts and Sciences, American Association for Advancement of Science, American Physical Society, Institute of Physics and New York Academy of Sciences, and a member of the National Academy of Sciences. 

His different honors embody receipt of two Guggenheim Fellowships; a Fulbright-Hays Special Fellowship; the Fritz London Memorial Award; and the NASA Distinguished Public Service Medal for his position in NASA’s Microgravity Research Program. 

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