PHAS Colloquia

Topologically Protected States of Matter Controlled by Light

by Jigang Wang (Iowa State University)

Tuesday, 10 November 2020 from to (America/Chicago)
Speaker: Dr. Jigang Wang (Physics & Astronomy, Ames Lab - U.S. DOE, Iowa State University)

Title: Topologically Protected States of Matter Controlled by Light

Abstract: Wide-scale adoption of quantum computing requires building devices in which fragile quantum states are protected from their noisy environments. One approach is based on topologically protected states (TPSs) that are theoretically immune to noise. The emerging topological electronics offer promise of realizing dissipationless photocurrent against impurity scattering and terahertz (THz) speed of transistor operation by switching band topology with negligible energy cost. The recent development of laser spectroscopy tools facilitates discovering and controlling TPSs by light at a THz clock rate. In this talk, I will discuss strategic advantages, with help of some recent examples from our research, of implementing this approach to measure, manipulate and harvest topological photocurrent, quantum coherence and light-induced symmetry switches in TPSs. This can potentially increase the ballistic transport length and lifetimes of topological currents beyond many micrometers and many nanoseconds, all at THz operating frequencies, the ‘holy grail’ for the next generation microelectronics. Reaching such a fundamental understanding and control of TPSs will advance the US National Quantum Initiative and Quantum Leap, one of National Science Foundation’s 10 Big Ideas.

This work was supported by the Ames Laboratory, the US Department of Energy, Office of Science, Basic Energy Sciences, Materials Science and Engineering Division and National Science Foundation.

About the speaker: He is currently a full professor in the Department of Physics and Astronomy at Iowa State University and senior staff scientist in Ames laboratory of US department of Energy. He received his Ph.D. from Rice University at 2005 and joined Lawrence Berkeley National Laboratory as a postdoctoral fellow from 2005-2008. He joined Iowa State University as a faculty member since 2008. His research broadly concerns with non-equilibrium quantum dynamics and coherent control using ultrafast spectroscopy and microscopy tools. He is recipient of the NSF CAREER award and Keck foundation award for quantum microscopy.


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Organised by Ioannis Chatzakis/ CMP