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


Contact: SunYoung Choi, (
Center for Quantum Coherence in Condensed Matter, KAIST

번호 일시 장소 연사 제목
272 Oct. 18 (Tue.), 1:30 PM  1st fl. #1323(E6-2)  Dr. Chan-Ho Yang, Department of Physics, KAIST  "Visualization of oxygen vacancy in motion and the interplay with electronic conduction"
271 July 10 (Wed.), 04:00 PM-  Academic Cltural Complex (E9) 5층 스카이라운지  Prof. Sidney Nagel/Young-Kee Kim  Public Lectures file
270 2015/08/04, 11PM  B501, Room Red, KI bldg. 5nd fl.  Dr. Eric Jin Ser Lee(Univ. of Manitoba, Canada)  Propagation of ultrasound through two- and three-dimensional strongly scattering media
269 Jun. 1(Wed) 10:30 AM  BK21 Conference Room (#1318, E6-2)  Dr. Noriaki Horiuchi, Editor, Nature Photonics  Welcome to Nature Photonics
268 October 15, 2020 (Thursday  CAPP Seminar Room #C303, Creation Hall (3F), KAIST Munji Campus  Prof. Gil-Ho Lee (POSTECH)  Graphene-based Josephson junction microwave bolometer file
267 2015/03/13, 2PM  Connect Room, KI Bldg.    The 15th Innovative Workshop on Soft/Bio Materials file
266 2015/12/09, 11AM  E4(KI Building), Connect room (2nd fl.)  Arjun G. Yodh (University of Pennsylvania)  Functional Imaging & Monitoring of Brain & Breast with Diffuse Light
265 2015/12/17, 11:00AM  E4(KI Building), Matrix Hall (2nd fl.)  Dr. Jung-Hoon Park (Purdue University)  Wavefront engineering for in-vivo Deep brain imaging
264 2015/07/23,1:30PM  E4, B401  Prof. Gilles Lérondel (Univ. of Technology of Troyes)  Enhanced ZnO based UV photonics and related applications file
263 Apr. 13(Wed.) 10:30Am  E6 #1323/zoom  Mingu Kang (Max Planck POSTECH Korea Research Initiative)  Harnessing topology and correlations from singularities in 3d-kagome metals
262 Jan. 11th(Tue), 15:00  E6 #1501  Soyeun Kim(UIUC)  Ultrafast optical studies on CDW collective modes of the Weyl-CDW (TaSe4)2I file
261 Jan. 26th (Tue), 13:00  E6 #1501  Dr. Hyojin Jung (NIMS)  An Introduction to Cohomology groups file
260 Jan. 25th (Tue), 15:00  E6 #1501/online  Junhyun Lee (Rutgers, the State University of New Jersey)  Emulating twisted double bilayer graphene with a multiorbital optical lattice file
259 10AM, 31th Mar.  E6 #1501/zoom  Dr. Samuel Begg (APCTP)  Weiss fields for Quantum Spin Dynamics file
258 10AM, 29th Mar. / 13:30 PM, 30th Mar.  E6 #1501/zoom, E6 #2502/zoom  Dr. RYO HANAI (APCTP)  Non-reciprocal phase transitions file
257 4pm, 28th April  E6 1323  유경식 (KAIST 전기및전자공학부)  (광학분야 특별세미나)Adiabaticity and symmetry in optical waveguide design
256 4pm, 14th April  E6 1323  신승우 (KAIST 물리학과)  (광학분야 특별세미나)Holographic tomography of dielectric tensors at optical frequency
255 4pm, 10th May  E6 1323  권혁준 (Korea Institute for Advanced Study, KIAS)  (광학분야 특별세미나)Testing quantum thermodynamics using quantum optics
254 4pm, 26th May  E6 1323  황민수 (Department of Physics, Korea University)  (광학분야 특별세미나)Topological photonic devices
253 June 23th (Thur), 11:00  E6 Room(#1322)  Sun Yool Park(Joint Institute for Laboratory Astrophysics (JILA) & University of Colorado)  JILA’s search for the electron’s Electric Dipole Moment (eEDM) to probe physics beyond the standard model file