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
420 2019-03-26 15:00  E6-2. 2st fl. #2501  Consideration of thermal Hall effect in frustrated and un-frustrated quantum magnets file
419 2019-01-07 15:00  E6-2. 2st fl. #2501  Many-Body Invariants for Multipoles in Higher-Order Topological Insulators file
418 2018-06-18 10:00  E6-2. 2nd fl. #2502  Rydberg electromagnetically induced transparency and microwave-to-optical conversion using Rydberg atoms file
417 2019-01-09 16:00  E6-2. 2nd fl. #2501  Molecular Mott state in the deficient spinel GaV4S8 file
416 2015-10-16 16:00  E6-2. 2nd fl. #2501  Fluctuations of entropy production in partially masked electric circuits
415 2015-09-14 14:00  E6-2. 2nd fl. #2501  Ultrafast X-ray Studies on Dynamics Matter in Extreme Conditions
414 2016-04-01 14:30  E6-2. 1st fl. #1501  Interference of single charged particles without a loop and dynamic nonlocality
413 2016-04-01 16:15  E6-2. 1st fl. #1501  Cotunneling drag effect in Coulomb-coupled quantum dots
412 2016-03-11 16:00  E6-2. 1st fl. #1501  Jan. Switching handedness of of chiral solitons in Z4 topological insulators
411 2016-04-08 13:30  E6-2. 1st fl. #1501  Theoretical Overview of Iron-based superconductors and its future
410 2016-03-11 13:30  E6-2. 1st fl. #1501  Topological phases of matter in nonequilibrium: Topology of the Wannier-Stark ladder
409 2022-05-25 16:00  E6-2. 1st fl. #1323 / Zoom  Uncovering New Lampposts for Dark Matter: Continuum or Conformal
408 2022-09-30 14:30  E6-2. 1st fl. #1323 & Zoom  Putting a spin on the Josephson effect file
407 2022-11-18 14:30  E6-2. 1st fl. #1323 & Zoom  Kondo cloud condensation in a highly-doped semiconductor metal file
406 2022-09-30 16:00  E6-2. 1st fl. #1323 & Zoom  Spin-orbit torque-based spintronic devices file
405 2022-11-18 16:00  E6-2. 1st fl. #1323 & Zoom  Qubits, new experimental tools for physics file
404 2022-11-09 16:00  E6-2. 1st fl. #1323  Radio Astronomy, Radio Interferometry, and Multi-wavelength Studies on Relativistic Jets
403 2022-11-10 16:00  E6-2. 1st fl. #1323  Probing the Origin of Cosmic Infrared Background and Future Prospects with SPHEREx
402 2022-06-10 16:00  E6-2. 1st fl. #1323  Fe5GeTe2의 나선형 자성특성과 자기저항의 전류밀도 의존성 연구 file
401 2022-06-10 14:30  E6-2. 1st fl. #1323  Combinatorial strategy for condensed matter physics: study on rare earth hexaborides thin films file