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
244 2016-06-14 16:00  Seminar Room (#2502, 2nd fl.)  Photonic quantum network based on multimode squeezed vacuums and single-photon subtraction
243 2016-06-16 16:00  #1323(E6-2, 1st fl.)  Quantum information processing using quantum dots and photonic crystal cavities
242 2018-06-18 10:00  E6-2. 2nd fl. #2502  Rydberg electromagnetically induced transparency and microwave-to-optical conversion using Rydberg atoms file
241 2017-06-02 14:30  E6-2. 1st fl. #1323  Quasiparticle Interference and Fourier transform scanning tunneling spectroscopy in WTe2 (Weyl semimetal) file
240 2017-06-02 16:00  #1323 (E6-2. 1st fl.)  Maxwell's demon in quantum wonderland file
239 2023-06-01 16:00  E6-2, #5301  Hall viscosity and topological phenomena
238 2018-06-14 10:00  E6-2, 2nd fl. #2502  Phonons and polariton-like particles in trapped ions for quantum computation and quantum simulation file
237 2023-06-14 16:00  CAPP Seminar Room C303, Creation Hall, KAIST Munji Campus  [CAPP seminar] EMC at CERN file
236 2016-06-14 15:00  #1323 (E6-2 1st fl.)  No-Insulation High Temperature Superconductor Magnet Technology for Compact, Reliable, and Low-Cost High Field DC Magnets
235 2023-06-14 16:00  E6-2, #2502  [High-Energy Theory Seminar]Vertex algebras and extended operators in 4d N=2 SCFTs
234 2023-06-15 16:00  CAPP Seminar Room C303, Creation Hall, KAIST Munji Campus  [CAPP Seminar] Cryogenic electronics for ion traps file
233 2023-06-16 13:00  E6-2, #2502  Quantum critical states under extreme conditions
232 2019-06-17 10:30  #1323, E6-2  Chiral Spintronics file
231 2018-06-22 16:00  #1323, E6-2  Tuning functional properties of BiFeO3 films using strain and growth chemistry file
230 2018-06-22 16:00  #1323, E6-2  Tuning functional properties of BiFeO3 films using strain and growth chemistry file
229 2023-06-22 16:00  CAPP Seminar Room C303, Creation Hall, KAIST Munji Campus  [CAPP Seminar] The muon g-2 puzzle file
228 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
227 2023-06-26 11:00  E6, Rm#1323  Quantum computing on magnetic racetracks with flying domain wall qubits
226 2019-06-27 14:00  #2502, E6-2  Gapless Kitaev Spin Liquid to Loop and String Gases file
225 2018-07-27 13:30  #1323, E6-2  Magnetic reversal of artificial spin ice file