School of Physics Fall Colloquium Series- Dr. Michael J. Manfra

Speaker: Dr. Michael J. Manfra

Host: Zhu-Xi Luo

Title: Quantum Mechanics, Identical Particles, and the Strange Case of Anyons…

Abstract: Electrons are indistinguishable particles - you cannot tell one electron from another by the color of its hair, or the shape of its ears, or the way it laughs. A basic tenet of quantum mechanics is that all elementary particles are either bosons or fermions, distinguished by their quantum statistics. Loosely speaking, bosons are social animals who like to flock together while fermions are solitary creatures that tend to avoid each other’s company. Ensembles of bosons or fermions behave differently due to differences in their underlying quantum statistics. Starting in the late 1970s it was theoretically conjectured that excitations that are neither bosons nor fermions may exist under special conditions in two-dimensional interacting electron systems. These unusual excitations were dubbed “anyons” by Frank Wilczek. Anyons possess fractional charges and fractional statistics. However, directly probing these properties presents experimental challenges. This colloquium will focus on the development of electronic Fabry-Pérot interferometers that resulted in the first direct observation of anyonic braiding statistics for the fractional quantum Hall state at n=1/3. These experiments demonstrate that ensembles of fundamental particles confined to reduced dimensions may act in concert to form new excitations with properties unlike anything previously observed in nature.

Bio: Michael Manfra is the Bill and Dee O’Brien Distinguished Professor of Physics and Astronomy, Professor of Materials Engineering, and Professor of Electrical and Computer Engineering at Purdue University. Manfra serves as the Director of the Purdue Quantum Science and Engineering Institute (PQSEI). He serves as Director of Microsoft Quantum West Lafayette. Mike received his A.B. from Harvard in 1992 and PhD from Boston University in 1999. Mike spent 2 years from 1998 to 2000 as a Postdoctoral Member of the Technical Staff at Bell Laboratories, Lucent Technologies and in 2001 he was promoted to Member of Technical Staff at Bell Laboratories where he conducted research in low-dimensional semiconductor systems. After 10 years at Bell Labs, Manfra joined the Purdue faculty in 2009. Mike was a Keck Foundation awardee in 2013 and was elected a Fellow of the American Physical Society in 2015. Manfra will receive the 2026 APS Oliver E. Buckley Condensed Matter Physics Prize.

Manfra and his team of approximately twenty researchers develop novel qubits and use nanoscale electronic devices to explore the interplay of topology and strong electronic correlations. In 2020, his group reported interferometric measurement of anyon braiding, giving experimental evidence for a theoretical prediction made 40 years earlier.