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
391 2022-07-21 16:00  CAPP Seminar Room C303, Creation Hall, KAIST Munji Campus  Quintessential axions file
390 2022-07-14 15:00  E6 #1501 & Zoom  Pure two-dimensional quantum electron liquid and its phase transition
389 2022-07-14 14:15  E6 #1501 & Zoom  Hund and electronic correlations in ruthenium-based systems
388 2022-07-14 13:30  E6 #1501 & Zoom  Electronic structure and anomalous transport properties of topological materials by first principle calculation
387 2022-06-23 11:00  E6 Room(#1322)  JILA’s search for the electron’s Electric Dipole Moment (eEDM) to probe physics beyond the standard model file
386 2022-06-10 16:00  E6-2. 1st fl. #1323  Fe5GeTe2의 나선형 자성특성과 자기저항의 전류밀도 의존성 연구 file
385 2022-06-10 14:30  E6-2. 1st fl. #1323  Combinatorial strategy for condensed matter physics: study on rare earth hexaborides thin films file
384 2022-06-10 11:00  Online seminar  Record-quality two-dimensional electron systems file
383 2022-06-03 11:00  E6-2 #1323  (응집물리 세미나) Theoretical Investigation of Exotic Quantum States in Low-dimensional Materials
382 2022-06-03 09:30  Online seminar  (Quantum-&Nano-Photonics Webinar) Seeing glass in a new light: reimagine chalcogenide photonics file
381 2022-05-30 16:00  E6, #1501  Light manipulation using 2D layered semiconductors
380 2022-05-27 11:00  Online seminar  Current Status and Future Plans of ADMX file
379 2022-05-26 16:00  E6 1323  (광학분야 특별세미나)Topological photonic devices
378 2022-05-25 16:00  E6-2. 1st fl. #1323 / Zoom  Uncovering New Lampposts for Dark Matter: Continuum or Conformal
377 2022-05-25 14:00  E6 Room(#2501)  Atomic-level insights into ferroelectric switching and preferred orientation of ultrathin hafnia file
376 2022-05-23 16:00  E6, #1501  Novel electronic transport in topological van der Waals magnets
375 2022-05-20 11:00  E6-1 #1323  (응집물리 세미나) Exploration of new polymorphs in van der Waals crystals
374 2022-05-19 16:00  E6-2. #1323 & Zoom  Chasing Long Standing Neutrino Anomalies with MicroBooNE
373 2022-05-19 15:00  online  (광학분야 특별세미나)Development of a multimodal optical system for improved disease diagnosis
372 2022-05-19 15:00  online  (광학분야 특별세미나)Development of a multimodal optical system for improved disease diagnosis