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
387 2018-05-11 14:30  E6-2. 1st fl. #1323  Disordered Floquet topological insulators file
386 2016-12-09 16:00  #1323(E6-2. 1st fl.  Shift Charge and Spin Photocurrents in Dirac Surface States of Topological Insulator
385 2022-05-13 14:30  Zoom webinar  Topological Superconducting Spintronics Towards Zero-Power Computing Technologies file
384 2021-07-29 14:00  Online seminar  Gravitationally Induced Dark Sector and Inflationary Dynamics file
383 2015-12-11 13:30  E6-2, #1323  Quantum spin liquid in the 1/3 depleted triangular lattice Ba3(Ru1-xIrx)Ti2O9
382 2016-03-11 13:30  E6-2. 1st fl. #1501  Topological phases of matter in nonequilibrium: Topology of the Wannier-Stark ladder
381 2018-11-01 16:00  #1323, E6-2  Direct holography from a single snapshot file
380 2022-08-18 10:00  E6-1 #1323  Disorder-driven phase transition in the second-order non-Hermitian skin effect
379 2023-04-27 11:00  E6-2 #1322  Inverse Shapiro steps and coherent quantum phase slip in superconducting nanowires
378 2015-07-16 16:00  E6-2, 1318  Next-generation ultrafast laser technology for nonlinear optics and strong-field physics
377 2018-10-26 16:00  #1323, E6-2  Coexisting triple-point and nodal-line topological magnons and thermal Hall effect in pyrochlore iridates file
376 2017-03-24 14:30  #1323 (1st fl. E6-2).  Topological Dynamics
375 2015-10-15 10:00  E6-2, 5th fl. #5318  Development of Large-Bore, High Field Magnets at the NHMFL
374 2023-06-22 16:00  CAPP Seminar Room C303, Creation Hall, KAIST Munji Campus  [CAPP Seminar] The muon g-2 puzzle file
373 2016-05-19 15:00  May 19, 2016 (Thur.) 3PM,  The CERN Resonant WISP Search: Development, Results and Lesson-Learned
372 2016-07-08 11:00  #1323(E6-2. 1st fl.)  Isostatic magnetism
371 2015-11-23 13:30  E6-2, #1323  What's Beyond the Standard Model? Lessons from Run I and what might come in Run II
370 2017-02-01 14:00  #1323(E6-2. 1st fl.)  Quantum electron optics using flying electrons
369 2019-09-10 15:00  E6-2. 1st fl. #1323  Two-Stage Kondo Effect file
368 2017-11-03 14:30  #1323 (1st fl., E6-2.)  Quantum Resistor-Capacitor Circuit with Majorana Edge States file