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
공지 2019/09/18 - 12/5  Seminar Room #1323  Prof. David Schuster and etc.  Fall 2019: Physics Seminar Serises
공지 2019/09/02 - 12/09  Seminar Room 1501  이호성 박사 (한국표준과학연구원) and etc.  Fall 2019: Physics Colloquium
49 2015/09/14, 2PM  E6-2. 2nd fl. #2501  Dr. Hae Ja Lee ( Stanford University, SLAC )  Ultrafast X-ray Studies on Dynamics Matter in Extreme Conditions
48 Jan.9 (Wed.), 04:00 PM  E6-2. 2nd fl. #2501  Dr. Heung-Sik Kim  Molecular Mott state in the deficient spinel GaV4S8 file
47 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
46 NOV. 23 (Fri), 03:00 PM  E6-2. 2st fl. #2501  Prof. Sang-Jin Sin  Entanglement string and Spin Liquid with Holographic duality file
45 JAN. 7 (Mon), 03:00 PM  E6-2. 2st fl. #2501  Dr. Byoung min Kang  Many-Body Invariants for Multipoles in Higher-Order Topological Insulators file
44 MAR. 26 (TUE), 0300 PM  E6-2. 2st fl. #2501  Prof. Jung Hoon Han  Consideration of thermal Hall effect in frustrated and un-frustrated quantum magnets file
43 Sep. 4 (Tue), 02:30 PM  E6-2. 2st fl. #2502  Dr. Changmin Lee, MIT  Ultrafast time- and angle-resolved photoemission spectroscopy (tr-ARPES) with extreme ultraviolet laser pulses file
42 May. 3 (Fri), 11:00 AM  E6-2. 2st fl. #2502  Prof. Changhee Sohn  Exotic Magnetism file
41 Apr. 08 (Fri.), 4:00 PM  E6-2. 5st fl. #1501  Dr. Changyoung Kim, SEOUL NATIONAL UNIV.  Spectroscopic studies of iron-based superconductors : what have we learned?
40 2018. 6. 22 10:00am ~ 11:50am  E6-6, Lecture Room 119 (1F)  Prof. Sang Bok Lee, Dept. of Chemistry and Biochemistry, Univ. of Maryland  Success in Research Career file
39 May 13 (Fri.) 4 PM  E6. #1501(1st fl.)  Dr. Hosub Jin, Dept. of Physics, UNIST  Graphene analogue in (111)- BaBiO3 bilayer heterostructures for topological electronics
38 May 13 (Fri.), 1:30 PM  E6. #1501(1st fl.)  Dr. Young-Woo Son, Dept. of Physics, KIAS  Aperiodic crystals in low dimensions
37 April 6, 2017 (Thu), 4:00 pm  IBS CAPP seminar room, Creation Hall (3F), KAIST Munji Campus  Prof. Youngjoon Kwon (Yonsei University)  For whom the Belle tolls
36 #1323(E6-2. 1st fl.)  Jul. 10th (Mon), 4pm  Dr. Duk Young Kim Los Alamos National Laboratory  “Intertwined Orders in a Heavy-fermion metal” file
35 2015/10/14, 6PM  KAIST Munji Campus Supex Hall  이창환 교수 (부산대학교 물리학과)  인터스텔라 영화 속의 물리 file
34 April 4, 2016 (Mon) - April 8, 2016 (Fri)  KAIST Natural Science Building (E6-2), RM #4314  Dr. Fritz Caspers (CERN)  Radio frequency engineering
33 Aug. 4, 2016 (Thu.), 2:30 pm  KAIST Natural Science Building (E6-5), EDU 3.0 Room(1st fl.)  Prof. Argyris Nicolaidis  Relational Logic (with applications to Quantum Mechanics, String Theory, Cosmology, Neutrino Oscillations, Statistical Mechanics)
32 2014/05/28, PM5  KI Building, Matrix Hall  이웅범 대표이사(LG이노텍)  부품소재산업이 미래다
31 4월 18일(월), 15:30~  KI빌딩(E4), 강의실 B501 (5F)  Prof. Robert A. DiStasio Jr. (Cornell University)  First Principles Approaches for Intermolecular Interactions: From Gas-Phase Dimers to Liquid Water and Molecular Crystal Polymorphism file
30 2017.1.9(Mon), 4PM  Lecture Hall, College of Natural Sciences [#1501,E6-2]  Prof. John Michael Kosterlitz, Brown University  Topological Defects and Phase Transitions" file