|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
|127||Dec. 15 (Fri.), 9:20 AM||E6-2, Lecture Room #1323||Prof. Jhinhwan Lee 외 9명||Workshop on Magnetism in Unconventional Superconductors 개최|
|126||Dec. 13-14(Wed.-Thu.) 13:30 PM||자연과학동 대형강의실 (1501호)||장기주 교수 외 9명||KAIST-KIAS Joint Workshop in Theoretical Sciences 개최|
|125||Dec. 12th (Mon)||1:30p.m. #1323(E6-2. 1st fl.)||Dongjoon Song , AIST||“Possible symmetry in the phase diagrams of electron- & hole-doped cuprate high-Tc superconductors”|
|124||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|
|123||Dec. 11 (Fri.), 04:00 PM||online||Hyobin Yoo(Sogang Univ.)||Atomic and electronic reconstruction at van der Waals interface in twisted 2D materials|
|122||Dec. 11 (Fri.), 02:30 PM||online||Myung Hwa Jung(Sogang Univ.)||Antisymmetric interlayer exchange coupling in magnetic multilayers|
|121||Dec 27 (Fri), 3:00 PM||#5318, E6-2||Han Gyeol Suh||The superconducting order parameter puzzle of Sr2RuO4|
|120||August. 6th (TUE), 14:00||E6 Room(#1323)||Kanghyun Chu||Visualization of in-plane piezoresponse vector fields|
|119||August. 1st (Thu), 14:00||E6 Room(#1323)||Hyeok Yoon||Low-density Superconductivity in SrTiO3 Probed by Planar Tunneling Spectroscopy|
|118||August. 16th (Fri), 14:00||E6 Room(#1323)||Jinxing Zhang||Multiferroic and Magnetoelectric Effects by Tailoring Interfacial Chemistry and Physics in Correlated Oxides|
|117||August. 14th (Wed.), 4:00PM,||Rm. 1323, E6||Prof. Nicolas Treps||Quantum Optics, at the heart of quantum metrology and quantum information|
|116||August 27 (Tue.), 4:00PM||Rm. 1323, E6||Hiroshi Eisaki||Critical current properties of Fe-based superconductors|
|115||August 1, 2018 at 11:00AM||양분순 빌딩 (E16-1) 207호||이대열 교수, 예일대 석좌교수||Future of AI: Is the brain a computer?|
|114||Aug. 4, 2016 (Thu.), 2:30 pm||KAIST Natural Science Building (E6-5), EDU 3.0 Room(1st fl.)||Prof. Argyris Nicolaidis||Relational Logic (with applications to Quantum Mechanics, String Theory, Cosmology, Neutrino Oscillations, Statistical Mechanics)|
|113||AUG. 31 (Thu.), 2 PM||#5318(E6-2. 5th fl.)||Prof. Hiroaki Ishizuka (The University of Tokyo)||“Berry phase and nonlinear response: photocurrent in noncentrosymmetric insulators and Weyl semimetals”|
|112||Aug. 17(Mon), 20:00~||Zoom webinar||Mark D. Stiles (NIST, USA)||Using magnetic tunnel junctions to compute like the brain|
|111||Aug. 16 (Wed.), 4 PM||#1322 (E6-2. 1st fl.)||Prof. Noejung Park (UNIST)||Phonon-driven spin-Floquet valleytro-magnetism|
|110||Aug, 25(Tue), 20:00~||Zoom webinar||Mark D. Stiles (NIST, USA)||KAIST Global Forum for Spin and Beyond (Second Forum)|
|109||April 6, 2017 (Thu), 4:00 pm||IBS CAPP seminar room, Creation Hall (3F), KAIST Munji Campus||Prof. Youngjoon Kwon (Yonsei University)||For whom the Belle tolls|
|108||April 6, 2016 (Wed), 3:30 PM||E6-2, RM #1323||Dr. Andrei Matlashov (Los Alamos National Laboratory)||Superconducting Quantum Interference Devices for Precision Detection|