visual
visual

세미나

  • HOME
  • >
  • 소식
  • >
  • 세미나
날짜 2016-10-18 15:00 
연사  
장소 E6-2. 1st fl. #1323 

“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 연사 제목
공지 2025-02-24 16:00    2025년 봄학기 콜로키움 안내
공지 2025-02-27 16:00    2025년 봄 물리학과 특별세미나 (광학/응집물리 분야)
374 2022-05-19 16:00    Chasing Long Standing Neutrino Anomalies with MicroBooNE
373 2022-05-19 15:00    (광학분야 특별세미나)Development of a multimodal optical system for improved disease diagnosis
372 2022-05-19 15:00    (광학분야 특별세미나)Development of a multimodal optical system for improved disease diagnosis
371 2022-05-18 16:00    Geometry, Algebra, and Quantum Field Theory
370 2022-05-16 16:00    Design synthetic topological matter with atoms and lights
369 2022-05-13 16:00    High-fidelity iToffoli gate for fixed-frequency superconducting qubits file
368 2022-05-13 14:30    Topological Superconducting Spintronics Towards Zero-Power Computing Technologies file
367 2022-05-12 16:00    New frontiers of electroweak physics at the LHC
366 2022-05-11 16:00    Gravity as a phenomenon in quantum dynamics
365 2022-05-10 16:00    (광학분야 특별세미나)Testing quantum thermodynamics using quantum optics
364 2022-05-09 16:00    Searching for new electronic properties in correlated material flatland
363 2022-05-02 16:00    What can we learn from the history of science and technology?(우리말강의)
362 2022-04-28 16:00    (광학분야 특별세미나)Adiabaticity and symmetry in optical waveguide design
361 2022-04-25 16:00    Ultrafast electron beam, a tool to explore the nanoscopic world of materials(우리말강의)
360 2022-04-15 11:00    (응집물리 세미나) First-principles studies of polar oxides and their applications file
359 2022-04-14 16:00    (광학분야 특별세미나)Holographic tomography of dielectric tensors at optical frequency
358 2022-04-13 10:30    Harnessing topology and correlations from singularities in 3d-kagome metals
357 2022-04-11 16:00    Emergence of Statistical Mechanics in Quantum Systems
356 2022-04-08 11:00    (응집물리 세미나) Flat-surface-assisted physical phenomena occurring in single crystal metal thin film file
355 2022-04-04- 16:00    New paradigms in Quantum Field Theory