visual
visual

세미나

  • HOME
  • >
  • 소식
  • >
  • 세미나
날짜 2016-10-18 15:00 
일시 Oct. 18 (Tue.), 3PM 
장소 E6-2. 1st fl. #1323 
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

 

Abstract:

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[1]. 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[3]. 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[6]. 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.

 

[1] Kurizki et.al., PNAS 112, 3866-3873 (2015).
[2] LaHaye et.al., Nature 459, 960-964 (2009).
[3] Suh et.al., Science 344, 1262-1265 (2014).
[4] Wollman et.al., Science 349, 952-955 (2015).
[5] Lei et.al., PRL 117, 100801 (2016).
[6] Nation et.al., PRA 93, 022510 (2016).

 

Contact: SunYoung Choi, (sunyoungchoi@kaist.ac.kr)
Center for Quantum Coherence in Condensed Matter, KAIST

번호 날짜 장소 제목
231 2019-05-30 16:00  #1323, E6-2  Tuning the excitonic properties of semiconductors with light-matter interactions file
230 2019-05-24 16:00  #1323, E6-2  Infrared spectroscopy study on metal-insulator transitions in layered perovskite iridates file
229 2019-05-21 16:00  #5318, E6-2  Classification of flat bands according to the band-crossing singularity of Bloch wave functions file
228 2019-05-09 16:00  #1323, E6-2  Quantum Optical Sensing Using Single Photons And Single Photon Emission from Single Emitters file
227 2019-05-08 16:00  E6 Room(#1323)  Imaging valley dependent electron transport in 2D semiconductors file
226 2019-05-03 11:00  E6-2. 2st fl. #2502  Exotic Magnetism file
225 2019-05-02 16:00  #1323, E6-2  Anomalous optical properties of halide perovskites file
224 2019-05-01 16:00  #1323, E6-2  Raman and x-ray scattering study on correlated electron systems: two case examples file
223 2019-04-26 16:00  #1323, E6-2  Robust Quantum Metrology using Strongly Interacting Spin Ensembles and Quantum Convolutional Neural Network file
222 2019-04-23 16:00  #1323, E6-2  From Mott physics to high-temperature superconductivity file
221 2019-04-19 16:00  E6-2. 1st fl. #1323  Graphene and hBN heterostructures file
220 2019-04-19 14:30  E6-2. 1st fl. #1323  A family of finite-temperature electronic phase transitions in graphene multilayers file
219 2019-04-19 11:00  #1323, E6-2  First-principles studies of semiconductors for solar cell applications file
218 2019-04-11 16:00  #1323, E6-2  Massive screening for cathode active materials using deep neural network file
217 2019-04-04 16:00  #1323, E6-2  Chiral spin-photon interaction at nanoscale file
216 2019-03-29 16:00  E6-2. 1st fl. #1323  Coherent Quantum Control and Magnetism on atoms – Trapped ion and ESR STM file
215 2019-03-29 14:30  E6-2. 1st fl. #1323  Epitaxial Multifunctional Oxide Thin Films for Novel Electronics file
214 2019-03-26 15:00  E6-2. 2st fl. #2501  Consideration of thermal Hall effect in frustrated and un-frustrated quantum magnets file
213 2019-03-21 16:00  RM. 1323, E6-2  Spring 2019: Physics Seminar Serises file
212 2019-02-25 16:00  Rm. 1501 (E6)  Spring 2019: Physics Colloquium file