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
451 2016-06-16 16:00  #1323(E6-2, 1st fl.)  Quantum information processing using quantum dots and photonic crystal cavities
450 2016-07-07 14:00  #1323(E6-2. 1st fl.)  Let there be topological superconductors
449 2016-07-08 11:00  #1323(E6-2. 1st fl.)  Isostatic magnetism
448 2016-07-08 14:00  #1323(E6-2. 1st fl.)  Electronic quasiparticles in the quantum dimer model
447 2016-07-28 16:00  #1323(E6-2. 1st fl.)  Low Dimensional Electrons: On the Road to Hybrid Quantum Systems
446 2016-08-04 14:30  KAIST Natural Science Building (E6-5), EDU 3.0 Room(1st fl.)  Relational Logic (with applications to Quantum Mechanics, String Theory, Cosmology, Neutrino Oscillations, Statistical Mechanics)
445 2016-09-02 14:30  E6-2(1st fl.), #1323  Nanoscale Thermal Physics: Seebeck Effect and Nanoscale Friction
444 2016-09-02 16:00  E6-2(1st fl) #1323  Quantum Electrical Transport in Topological Insulator Nanowires
443 2016-09-05 16:00  Natual Scien Bldg.(E6)m #1501  Physics Colloquium : 2016 Fall file
442 2016-09-21 16:00  E6-2. #2502(2nd fl.)  Entanglement probe of two-impurity Kondo physics
441 2016-09-22 15:30  #1323(E6-2, 1st fl.)  Polarized 3He, Polarized Neutrons and New Interactions beyond the Standard Model
440 2016-09-22 15:30  #1323(E6-2, 1st fl.)  Polarized 3He, Polarized Neutrons and New Interactions beyond the Standard Model
439 2016-09-29 16:00  E6-2, #1323  2016 Fall, Physics Seminar Serises file
438 2016-09-29 16:00  E6-2 #1323 (1st floor)  Large-scale Silicon Photonic MEMS Switches
437 2016-09-29 16:00  E6-2. #2501(2nd fl.)  Exploring the phase diagram of BaBiO3: epic voyage of just another bad trip?
436 2016-10-07 13:30  E6-2. #1323(1st fl.)  “Symmetry and topology in transition metal dichalcogenide?”
435 2016-10-07 16:00  E6-2. #1323(1st fl.)  “Tilt engineering of 4d and 5d transition metal oxides?”
434 2016-10-17 11:00  #1323,(E6-2, 1st fl.)  IMS and examples of the studies on optoelectronic materials
433 2016-10-18 13:30  1st fl. #1323(E6-2)  "Visualization of oxygen vacancy in motion and the interplay with electronic conduction"
» 2016-10-18 15:00  E6-2. 1st fl. #1323  “Hybrid quantum systems with mechanical oscillators”