visual
visual

세미나

  • HOME
  • >
  • 소식
  • >
  • 세미나
장소 #5318(5th fl.) 
일시 Nov. 18th (Fri) 10:30 a.m. 
연사 Dr. 최 순 원, Havard University 

Non-equilibrium many-body spin dynamics in diamond

 

Dr. 원, Havard University

Nov. 18th (Fri) 10:30 a.m., #5318(5th fl.)

 

 

Abstract:

In this talk, we will discuss two recent developments in non-equilibrium quantum dynamics of strongly interacting many-body systems: I. critically slow thermalization in a disordered dipolar spin ensemble [1] and II. the observation of discrete time crystalline order [2]. Both of these experiments were enabled by a high density ensemble of nitrogen-vacancy (NV) color centers in diamond [3]. As a mixture of theory and experiments, the talk will be self-contained and pedagogical, reviewing some of basic concepts in many-body localization, Floquet time-crystal, spin properties of NV centers and experimental techniques to manipulate and engineer the dynamics.

Part I:

Statistical mechanics underlies our understanding of macroscopic quantum systems. It is based on the assumption that out-of-equilibrium systems rapidly approach their equilibrium states, forgetting any information about their microscopic initial conditions. This fundamental paradigm is challenged by disordered systems, in which a slowdown or even absence of thermalization is expected. By controlling the spin states of the ~10^6 NV centers, we observe slow, sub-exponential thermalization consistent with power laws that exhibit disorder-dependent exponents; this behavior is modified at late times owing to many-body interactions. These observations are quantitatively explained by a resonance counting theory that incorporates the effects of both disorder and interactions

Part II:

The interplay of periodic driving, disorder, and strong interactions has recently been predicted to result in exotic ``time-crystalline'' phases, which spontaneously break the discrete time-translation symmetry of the underlying drive. We report the experimental observation of such discrete time-crystalline order and the observation of long-lived temporal correlations at integer multiples of the fundamental driving period. We experimentally identify the phase boundary and find that the temporal order is protected by strong interactions; this order is remarkably stable against perturbations, even in the presence of slow thermalization. We provide a theoretical description of approximate Floquet eigenstates of the system based on product state ansatz and predict the phase boundary, which is in qualitative agreement with our observations.

 

[1] G. Kucsko et al, arXiv:1609.08216

[2] S. Choi et al, arXiv:1610.08057

[3] J. Choi et al, arXiv:1608.05471

 

Contact: Eun-Gook Moon, Physics Dept., (egmoon@kaist.ac.kr)

 

번호 일시 장소 연사 제목
208 August. 16th (Fri), 14:00  E6 Room(#1323)  Jinxing Zhang  Multiferroic and Magnetoelectric Effects by Tailoring Interfacial Chemistry and Physics in Correlated Oxides file
207 May. 17(Mon) 17:00  Zoom webinar  Jing Shi (UC Riverside, USA)  Spin current generation and detection in uniaxial antiferromagnets file
206 May. 8th (Wed), 16:00  E6 Room(#1323)  Jieun Lee  Imaging valley dependent electron transport in 2D semiconductors file
205 May. 8th (Wed), 16:00  E6 Room(#1323)  Jieun Lee  Imaging valley dependent electron transport in 2D semiconductors file
204 June 27 (Thu), 2:00 PM  #2502, E6-2  Hyun-Yong Lee  Gapless Kitaev Spin Liquid to Loop and String Gases file
203 Jun. 16 (Thu) 4PM  #1323(E6-2, 1st fl.)  Hyochul Kim, Samsung Advanced Institute of Technology  Quantum information processing using quantum dots and photonic crystal cavities
202 Dec. 11 (Fri.), 04:00 PM  online  Hyobin Yoo(Sogang Univ.)  Atomic and electronic reconstruction at van der Waals interface in twisted 2D materials
201 August. 1st (Thu), 14:00  E6 Room(#1323)  Hyeok Yoon  Low-density Superconductivity in SrTiO3 Probed by Planar Tunneling Spectroscopy file
200 August 27 (Tue.), 4:00PM  Rm. 1323, E6  Hiroshi Eisaki  Critical current properties of Fe-based superconductors file
199 January 17 (Fri), 4:00 PM  #1323, E6-2  Hiroki Ikegami  Symmetry Breaking and Topology in Superfluid 3He file
198 September 26 (Thu.), 16:00 PM  #1323, E6-2  Han Seb Moon  Entanglement Swapping with Autonomous Polarization-Entangled Photon-Pairs from Warm Atomic Ensemble file
197 December 27(Fri.), 15:00  E6-2,#5318  Han Gyeol Suh  The superconducting order parameter puzzle of Sr2RuO4 file
196 Dec 27 (Fri), 3:00 PM  #5318, E6-2  Han Gyeol Suh  The superconducting order parameter puzzle of Sr2RuO4 file
195 May. 12(Thu), 4pm  E6-2. #1323 & Zoom  Dr.Philip Chang (University of California San Diego, Department of Physics)  New frontiers of electroweak physics at the LHC
194 May. 19(Thu), 4pm  E6-2. #1323 & Zoom  Dr.Jay Hyun Jo (Yale University, Department of Physics)  Chasing Long Standing Neutrino Anomalies with MicroBooNE
193 May. 18(Wed), 4pm  E6-2. #1323 & Zoom  Dr.Heeyeon Kim (Rutgers University, Department of Physics and Astronomy)  Geometry, Algebra, and Quantum Field Theory
» Nov. 18th (Fri) 10:30 a.m.  #5318(5th fl.)  Dr. 최 순 원, Havard University  Non-equilibrium many-body spin dynamics in diamond
191 Oct. 27th(Thu) 4PM  #1323(E6-2)  Dr. 이 강 희, KAIST, Mechnical Engineering  Terahertz Metal Optics
190 June 28 (Fri.), 13:30 PM  #1323, E6-2  Dr. Yusuke Kozuka  Magnetic domains and domain wall conduction in pyrochlore iridate thin films and heterostructures file
189 Apr. 08 (Fri.), 13:30 PM  E6-2. 1st fl. #1501  Dr. Yunkyu Bang, Chonnam National Univ.  Theoretical Overview of Iron-based superconductors and its future