Talk: June 7, 2019

High-frequency (HF) electron spin resonance (ESR) spectroscopy and ESR based quantum computing

Electron spin resonance (ESR) spectroscopy is a powerful and versatile tool for probing and studying local structures and dynamic properties of various compounds in liquids and solids; for example, structures and dynamics in biological molecules, magnetic structures and relaxations in magnetic molecules and quantum coherence in solid-state spin systems.

High-frequency (HF) ESR spectroscopy is an emerging technique enabling finer spectral resolution, better absolute sensitivity, and improved time resolution. I will first talk about the development of a HF ESR spectrometer at the University of Sothern California [1,2]. The spectrometer consisting of a high-power HF solid-state source, a quasioptical system, a phase-sensitive superheterodyne detection system, a 12.1 Tesla cryogenic-free superconducting magnet, and a 4He cryostat enables pulsed ESR measurements with a few hundred nanosecond pulses. I will also discuss some of its unique experimental capabilities such as double electron-electron resonance and dynamical decoupling to study paramagnetic impurities existing in synthetic diamond crystals.

If time permits, I will then talk about our efforts on ESR based quantum computing at the University of Waterloo, particularly experimental realization of a quantum algorithm known as heat-bath algorithmic cooling using a solid-state electron-nuclear coupled system [3]. A home-built pulsed X-band ESR spectrometer with arbitrary waveform generator is employed (electron-nuclear double resonance capability was added later) [4]. Major focus has been understanding noises and improving quantum control which is critical in the field of quantum computing and quantum information processing [5,6].

[1] F. H. Cho, V. Stepanov, and S. Takahashi, Review of Scientific Instruments 85, 075110 (2014).
[2] F. H. Cho, V. Stepanov,C. Abeywardana, and S. Takahashi, Methods in Enzymology 563, 95 (2015)
[3] D. K. Park, G. Feng, R. Rahimi, S. Labruyère, T. Shibata, S. Nakazawa, K. Sato, T. Takui, R. Laflamme, and J. Baugh, Quantum Information Processing 14, 2435 (2015)
[4] D. K. Park, G. Feng, R. Rahimi, J. Baugh, and R. Laflamme, Journal of Magnetic Resonance 267, 68 (2016)
[5] G. Feng, J. J. Wallman, B. Buonacorsi, F. H. Cho, D. K. Park, T. Xin, D. Lu, J. Baugh, and R. Laflamme, Physical Review Letters 117, 260501 (2016)
[6] G. Feng, F. H. Cho, H. Katiyar, J. Li, D. Lu, J. Baugh, and R. Laflamme, Physical Review A 98, 052341 (2018)