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
419 2023-12-14 16:00  CAPP Seminar Room C303, Creation Hall, KAIST Munji Campus  Superconducting qubits for large-scale quantum computers file
418 2024-01-25 16:00  CAPP Seminar Room C303, Creation Hall, KAIST Munji Campus  [CAPP seminars] Detecting Gravitational Waves by Elecromagnetic Cavity
417 2022-09-21 16:00  College of Natural Science E6-2, Rm. 1323  Materials and Device Nanofabrication of Optical Metasurfaces file
416 2015-03-13 14:00  Connect Room, KI Bldg.  The 15th Innovative Workshop on Soft/Bio Materials file
415 2015-12-09 11:00  E4(KI Building), Connect room (2nd fl.)  Functional Imaging & Monitoring of Brain & Breast with Diffuse Light
414 2015-12-17 11:00  E4(KI Building), Matrix Hall (2nd fl.)  Wavefront engineering for in-vivo Deep brain imaging
413 2015-07-23 13:30  E4, B401  Enhanced ZnO based UV photonics and related applications file
412 2023-04-28 11:00  E6 #1323  Tkachenko wave: From the modern field theory viewpoint
411 2022-10-06 13:00  E6 #1323  Counting States with Global Symmetry
410 2023-05-17 14:00  E6 #1323  Optical Response in the multilayer thin films
409 2022-04-13 10:30  E6 #1323/zoom  Harnessing topology and correlations from singularities in 3d-kagome metals
408 2022-01-11 15:00  E6 #1501  Ultrafast optical studies on CDW collective modes of the Weyl-CDW (TaSe4)2I file
407 2022-01-26 13:00  E6 #1501  An Introduction to Cohomology groups file
406 2022-07-14 13:30  E6 #1501 & Zoom  Electronic structure and anomalous transport properties of topological materials by first principle calculation
405 2022-07-14 14:15  E6 #1501 & Zoom  Hund and electronic correlations in ruthenium-based systems
404 2022-07-14 15:00  E6 #1501 & Zoom  Pure two-dimensional quantum electron liquid and its phase transition
403 2022-08-01 10:00  E6 #1501 & Zoom  [Update 세미나 영상] James Webb Space Telescope & OTE Commissioning
402 2022-10-24 16:00  E6 #1501(공동강의실)  Physics Colloquim(Fall 2022) file
401 2022-01-25 15:00  E6 #1501/online  Emulating twisted double bilayer graphene with a multiorbital optical lattice file
400 2022-03-31 10:00  E6 #1501/zoom  Weiss fields for Quantum Spin Dynamics file