[Joint CQSE & NCTS Seminar] Electromagnetic field- and surface acoustic wave-induced decoherence in a ballistic quantum interferometer
Title: [Joint CQSE & NCTS Seminar] Electromagnetic field- and surface acoustic wave-induced decoherence in a ballistic quantum interferometer
Speaker: Prof. Jeng-Chung Chen (NTHU)
Time: 2024/5/10 (Fri.) 14:30-15:30
Place: NCTS Physics Lecture Hall, 4F, Chee-Chun Leung Cosmology Hall, NTU
Online: https://nationaltaiwanuniversity-zbh.my.webex.com/nationaltaiwanuniversity-zbh.my/j.php?MTID=mb00e764354d74a2b322c54de4cfdf7da
Abstract
We report on the studies of decoherence processes of a ballistic quantum interferometer in the presence of a radio-frequency (RF) electromagnetic (EM) field and surface acoustic wave (SAW). The device comprises an Aharonov-Bohm (AB) ring sandwiched between two interdigital transducers (IDTs), where the AB ring serves as a phase sensor and the IDTs function as a controlled source of environmental noise. By employing the IDTs with RF signal to launch a SAW train through the ring, we extract the decoherence rate, associated with the dephasing process induced by the thermal fluctuations of the RF-EM field, SAW, and the acoustoelectric current, from the AB oscillation amplitude. Consequently, we find the RF-EM field-induced phase-breaking effects without thermal heating and, more importantly, identify the optimal conditions for operating SAW to minimize dephasing. The underlying mechanism responsible for the decoherence is attributed to the enhancement of charge-charge interactions in the presence of the RF-EM field and SAW. Our findings have significant implications for the development of flying-qubit techniques utilizing surface acoustic effects, offering new avenues for solid-state quantum information processing and quantum computing applications.Biography
https://drive.google.com/file/d/1vaJBfNXRGzczttwkqUq3fwVp99Zc1eRR/view?usp=sharing
Research Experience
08/2016-present Professor in the Department of Physics at National Tsing-Hua University
03/2015-07/2015 Visiting scholar, IBM Thomas J. Watson Research Center, Yorktown Heights, NY, USA
08/2010-present Associate Professor in the Department of Physics at National Tsing-Hua University
08/2006-08/2010 Assistant Professor in the Department of Physics at National Tsing-Hua University studying the physics of nanostructure.
01/2004-07/2006 Postdoctoral researcher under Prof. S. Komiyama in the Department of Basic Science at the University of Tokyo and Japan Science and Technology Agency (JST)
Education
08/1999–12/2003 Ph.D. in Physics at Purdue University, U.S.A.
01/2002–12/2003 M.S. in Electrical and Computer Engineering at Purdue University, U.S.A.
08/1993–06/1995 M.S. in Physics at National Tsing Hua University, Taiwan
08/1989–06/1993 Undergraduate Studies in Physics at National Central University, Taiwan
Research Interests
Circuit-QED.
Quantum transport in nanostructures.
Submillimeter photon detector and Thz image.
Magnetism: novel magnetic material, device.
Superconductivity: application, device.
