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
228 Nov. 3 (Fri.), 4:00 PM  #1323 (1st fl., E6-2.)  Dr. SungDae Ji (Max Planck POSTECH/Hshinchu Center (MPK))  Expedition to the Kitaev Quantum Spin Liquid: Hunting for Majorana fermions file
227 April 13 (Fri.), 10am  #1323 (E6-2, 1st fl.)  Dr. Sungkun Hong  Quantum meets Mechanics: from Quantum Information to Fundamental Research file
226 May 1 (Wed), 4:00 PM  #1323, E6-2  Dr. Sungkyun Choi  Raman and x-ray scattering study on correlated electron systems: two case examples file
225 May. 25(Wed), 4pm  E6-2. 1st fl. #1323 / Zoom  Dr. Sungwoo Hong (Enrico Fermi Institute at University of Chicago)  Uncovering New Lampposts for Dark Matter: Continuum or Conformal
224 May. 11(Wed), 4pm  E6-2. #1323 & Zoom  Dr. Sunok Josephine Suh (Kavli Institute for Theoretical Physics)  Gravity as a phenomenon in quantum dynamics
223 2015/11/28, 10AM  E6-2, #1323  Dr. Suyong Jung (Korea Research Institute of Standards and Science)  Electron Tunneling Spectroscopy of Single and Bilayer Graphene with Hexagonal Boron Nitride as Tunneling Barrier
222 May. 14 (Fri.), 02:30 PM  Online seminar  Dr. Suyong Jung(KRISS)  Electrically tunable spin valve effect in vertical van-der-Waals magnetic tunnel junctions file
221 Apr. 2 (Fri.), 02:30 PM  Online(Zoom)  Dr. Tae Hyun Kim (SNU)  Quantum computing and entanglement generation using trapped ions and photons
220 2016/03/11 4 PM  E6-2. 1st fl. #1501  Dr. Tae-Hwan KIM (POSTECH)  Jan. Switching handedness of of chiral solitons in Z4 topological insulators
219 Mar. 29 (Fri.), 04:00 PM  E6-2. 1st fl. #1323  Dr. Taeyoung Choi  Coherent Quantum Control and Magnetism on atoms – Trapped ion and ESR STM file
218 Jun. 18 (MON), 10:00 AM  E6-2. 2nd fl. #2502  Dr. Thibault VOGT  Rydberg electromagnetically induced transparency and microwave-to-optical conversion using Rydberg atoms file
217 October 16 (Tue.), 10:00 AM  #1323, E6-2  Dr. Won-Ki Cho  Capturing protein cluster dynamics and gene expression output in live cells file
216 2015/11/10, 4PM  E6-2, #1323  Dr. Woosuk Bang (Physics division, Los Alamos National Laboratory)  Rapid heating of matter using high power lasers
215 2015/12/01, 4PM  E6-2, #1323  Dr. Yeong Kwan Kim(Lawrence Berkeley National Laboratory, USA)  Introducing extra dimensions to spectroscopic studies of advanced quantum materials
214 Sep. 02(Fri) 2:30 PM  E6-2(1st fl.), #1323  Dr. Yong-Hyun Kim,Graduate School of Nanoscience and Technology, KAIST  Nanoscale Thermal Physics: Seebeck Effect and Nanoscale Friction
213 Sep. 02(Fri) 4:00 PM  E6-2(1st fl) #1323  Dr. Yong-Joo Doh, Department of Physics and Photon Science, GIST  Quantum Electrical Transport in Topological Insulator Nanowires
212 October 15 (Mon.), 16:00 PM  #1323, E6-2  Dr. Yongjoo Baek  Universal properties of macroscopic current-carrying systems file
211 April 11 (Wed), 1:30pm  #1323 (E6-2, 1st fl.)  Dr. Yongsoo Yang  Probing 3D Structure and Physical Properties of Materials at the Single-Atom Level file
210 Jun. 10 (Fri.), 11:00 AM  Online seminar  Dr. Yoon Jang Chung(Laboratory for Physical Sciences, University of Maryland)  Record-quality two-dimensional electron systems file
209 May. 13 (Fri.), 04:00 PM  자연과학동(E6-2) 1st fl. #1323  Dr. Yosep Kim(Center for Quantum Information, KIST)  High-fidelity iToffoli gate for fixed-frequency superconducting qubits file