visual
visual

세미나

  • HOME
  • >
  • 소식
  • >
  • 세미나
날짜 2016-11-18 10:30 
연사  
장소 #5318(5th fl.) 

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 날짜 연사 제목
공지 2025-02-24 16:00    2025년 봄학기 콜로키움 안내
공지 2025-02-27 16:00    2025년 봄 물리학과 특별세미나 (광학/응집물리 분야)
385 2019-04-11 16:00    Massive screening for cathode active materials using deep neural network file
384 2018-09-20 16:00    Toward Cancer Treatment Using Terahertz Radiation: Demethylation of Cancer DNA file
383 2018-09-20 16:00    Toward Cancer Treatment Using Terahertz Radiation: Demethylation of Cancer DNA file
382 2018-10-18 16:00    Applications of nonlinear optics for condensed matter researches file
381 2018-05-09 16:00    Recent advances in thermoelectric bulk composites file
380 2017-01-09 16:00    Topological Defects and Phase Transitions" file
379 2016-07-28 16:00    Low Dimensional Electrons: On the Road to Hybrid Quantum Systems
378 2019-04-23 16:00    From Mott physics to high-temperature superconductivity file
377 2022-07-21 16:00    Quintessential axions file
376 2019-11-14 16:00    Semi-classical model of polariton propagation file
375 2017-12-15 09:20    Workshop on Magnetism in Unconventional Superconductors 개최 file
374 2024-05-01 16:00    [High Energy Theory Seminar] Across the Mass Spectrum: Utilizing Small-Scale Structures to Probe Dark Matters
373 2019-11-07 16:00    Integrated quantum photonics with solid-state quantum emitters file
372 2018-05-29 16:00    Investigation on metal nanostructure/semiconductor junction and its applications file
371 2020-10-23 14:00    Plasmon spectroscopy of low-dimensional superconductors in fluctuating regime file
370 2025-02-25 14:00  Prof. Igor Di Marco  Dynamical mean-field theory for strongly correlated materials file
369 2024-05-16 16:00    [High Energy Theory Seminar] Conformal Collider Physics
368 2018-07-13 14:00    Loop Induced Single Top Partner Production and Decay at the LHC
367 2018-12-11 16:00    Natural compact representation of Matsubara Green’s functions: applications to analytic continuation and quantum many-body simulations file
366 2017-08-31 14:00    “Berry phase and nonlinear response: photocurrent in noncentrosymmetric insulators and Weyl semimetals” file