|장소||E6-2. 1st fl. #1323|
|일시||Oct. 18 (Tue.), 3PM|
|연사||Dr. JunHo Suh, Korea Research Institute of Standards and Science|
“Hybrid quantum systems with mechanical oscillators”
Dr. JunHo Suh, Korea Research Institute of Standards and Science
Oct. 18 (Tue.), 3PM, E6-2. 1st fl. #1323
Quantum machines are actively pursued to harness quantum coherence and entanglement as new resources for information processing and precision sensing. Among those activities, hybrid quantum systems are recognized as a promising platform for building multi-functional quantum machines by connecting quantum states in different physical domains, and mechanical oscillators are accepted as important components in the quantum hybrids. In this talk, I review recent examples of hybrid quantum systems involving mechanical oscillators strongly coupled to electrons and photons. In the first part, a quantum electro-mechanical system is introduced. A cooper-pair box qubit is electrostatically coupled to a nanomechanical oscillator. A dispersive measurement of qubit states is achievable through high-quality read-out of nanomechanical motion, which also maintains qubit coherence proved via microwave spectroscopy and Landau-Zener interference. In the second part, mechanical oscillators coupled to microwave photons, or "quantum opto-mechanical systems", are described, where radiation pressure mediates the interaction between photons and the mechanical oscillator. Photons act as a probe for mechanical motion in this case, and a fundamental limit in measurement sensitivity arises due to Heisenberg's uncertainty principle, as known as quantum standard limit(SQL). By carefully measuring mechanical motion in quadratures, we identify the fundamental back-action from photons which mandates SQL, and also demonstrate a novel scheme known as quantum non-demolition measurement (QND) which allows a precise measurement without back-action in one quadrature of motion. When the coupling between the microwave photons and mechanical motion is strong enough, the back-action from photons start modifying quantum noise in mechanical oscillators and produced mechanical quantum squeezed states[4,5]. Finally, it is expected that one could approach ultra-strong coupling regime as photon-mechanical oscillator coupling strength increases, where single photon coupled to mechanical motion dominates the hybrid system. Mechanical states in the ultra-strong coupling limit deviate from well-known number states which could open a new paradigm for controlling mechanical quantum states. A quantum dot system embedded in a nanowire is proposed to be a candidate to reach this interesting regime, and our recent progress toward this direction is dissussed.
 Kurizki et.al., PNAS 112, 3866-3873 (2015).
 LaHaye et.al., Nature 459, 960-964 (2009).
 Suh et.al., Science 344, 1262-1265 (2014).
 Wollman et.al., Science 349, 952-955 (2015).
 Lei et.al., PRL 117, 100801 (2016).
 Nation et.al., PRA 93, 022510 (2016).
Contact: SunYoung Choi, (firstname.lastname@example.org)
Center for Quantum Coherence in Condensed Matter, KAIST
|239||Sep. 27 (Fri.), 02:30 PM||E6-2. 1st fl. #1323||Dr. Joon Sue Lee||Spin-charge conversion in topological insulators for spintronic applications|
|238||Sep. 27 (Fri.), 04:00 PM||E6-2. 1st fl. #1323||Dr. Jindong Song||0D/1D/2D/3D III-V materials grown by MBE for Optelectronics|
|237||Sep. 10 (Tue.), 03:00 PM||E6-2. 1st fl. #1323||Dr. Mikhail Kiselev||Two-Stage Kondo Effect|
|236||Apr. 19 (Fri.), 02:30 PM||E6-2. 1st fl. #1323||Dr. YoungWoo Nam||A family of finite-temperature electronic phase transitions in graphene multilayers|
|235||Apr. 19 (Fri.), 04:00 PM||E6-2. 1st fl. #1323||Dr. Seok Kyun Son||Graphene and hBN heterostructures|
|234||Mar. 29 (Fri.), 04:00 PM||E6-2. 1st fl. #1323||Dr. Taeyoung Choi||Coherent Quantum Control and Magnetism on atoms – Trapped ion and ESR STM|
|233||Mar. 29 (Fri.), 02:30 PM||E6-2. 1st fl. #1323||Dr. Seung Hyub Baek||Epitaxial Multifunctional Oxide Thin Films for Novel Electronics|
|232||DEC. 27 (Thu), 04:00 PM||E6-2. 1st fl. #1323||Prof. Na Young Kim||Quantum Innovation (QuIN) Laboratory|
|231||Dec. 26 (Wed.), 04:00 PM||E6-2. 1st fl. #1323||Dr. Isaac H. Kim||Brane-like defect in 3D toric code|
|230||DEC. 16~18 (Sun~Tue)||E6-2. 1st fl. #1323||Prof. Keisuke Totsuka||Lectures on 2d Conformal Field Theory|
|229||DEC. 11 (Tue), 04:00 PM||E6-2. 1st fl. #1323||Prof. Hiroshi Shinaoka||Natural compact representation of Matsubara Green’s functions: applications to analytic continuation and quantum many-body simulations|
|228||Dec. 7 (Fri.), 04:00 PM||E6-2. 1st fl. #1323||Dr. Joon Ho Jang||Novel probes of interacting electrons in 2D systems|
|227||Dec. 7 (Fri.), 02:30 PM||E6-2. 1st fl. #1323||Dr. Gyung Min Choi||Spin generation from heat and light in metals|
|226||Nov. 9 (Fri.), 04:00 PM||E6-2. 1st fl. #1323||Dr. Donghun Lee||Quantum sensing and imaging with diamond defect centers for nano-scale spin physics|
|225||Nov. 9 (Fri.), 02:30 PM||E6-2. 1st fl. #1323||Dr. Pilkyung Moon||Moiré superlattices – from twisted bilayer graphene to quasicrystal|
|224||Oct. 12 (Fri.), 04:00 PM||E6-2. 1st fl. #1323||Dr. HyungWoo Lee||Direct observation of a two-dimensional hole gas at oxide interfaces|
|223||Oct. 12 (Fri.), 02:30 PM||E6-2. 1st fl. #1323||Dr. Daniel Kyungdeock Park||Quantum Advantage in Learning Parity with Noise|
|222||Jun. 01 (Fri.), 11:00 AM||E6-2. 1st fl. #1323||Dr. Seung Sae Hong||Topological phases in low-dimensional quantum materials|
|221||May. 17 (Thu.), 01:30 PM||E6-2. 1st fl. #1323||Prof. Yong-Baek Kim University of Toronto||Quantum Spin Liquid in Kitaev Materials|
|220||May. 11 (Fri.), 04:00 PM||E6-2. 1st fl. #1323||Dr. Nam Kim||암페어 단위 재정의와 단전자 펌프 소자 개발|