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)
465 2015-12-17 11:00    Wavefront engineering for in-vivo Deep brain imaging
464 2022-12-20 16:00    Studying Baryonic Flow Across the Cosmic Scales Using Radio and Millimeter Wavelength Experiments
463 2016-10-18 15:00    “Hybrid quantum systems with mechanical oscillators”
462 2016-07-08 14:00    Electronic quasiparticles in the quantum dimer model
461 2015-11-24 16:00    Topology-based understanding of spin dynamics in inhomogeneously magnetized systems
460 2022-04-01 16:00    High-field Electron Transport and Interaction Induced Phenomena in 2D Materials file
459 2018-11-29 16:00    양자 칸델라 실현을 위한 단일 광자 발생장치 개발 file
458 2024-03-07 16:00    [CAPP seminars] Development of Superconducting Transition Edge Sensors at SRON file
457 2021-06-11 16:00    Pseudogap in surface-doped black phosphorus file
456 2016-11-11 13:30    Bandgap Engineering of Black Phosphorus
455 2016-04-01 14:30    Interference of single charged particles without a loop and dynamic nonlocality
454 2016-05-31 16:00    Understanding 3D tokamak physics towards advanced control of toroidal plasma
453 2023-07-18 11:00    Non-Hermitian Casimir Effect of Magnons
452 2024-06-13 16:00    Magnonic $\varphi$ Josephson junction and its non-Hermitian Josephson diode effect
451 2023-09-14 16:00    [CAPP seminar] Dark matter searches in Water Cherenkov Detectors file
450 2018-05-11 14:30    Disordered Floquet topological insulators file
449 2016-12-09 16:00    Shift Charge and Spin Photocurrents in Dirac Surface States of Topological Insulator
448 2022-05-13 14:30    Topological Superconducting Spintronics Towards Zero-Power Computing Technologies file
447 2021-07-29 14:00    Gravitationally Induced Dark Sector and Inflationary Dynamics file
446 2015-12-11 13:30    Quantum spin liquid in the 1/3 depleted triangular lattice Ba3(Ru1-xIrx)Ti2O9