visual
visual

세미나

  • HOME
  • >
  • 소식
  • >
  • 세미나
날짜 2016-09-21 16:00 
일시 4pm, Sep. 21 (Wed. 
장소 E6-2. #2502(2nd fl.) 
연사 Dr. Henrik Johannesson , University of Gothenburg (Sweden) and Beijing Computational Science Research Center (China) 

Entanglement probe of two-impurity Kondo physics

 

4pm, Sep. 21 (Wed.), E6-2. #2502(2nd fl.)
Dr. Henrik Johannesson , University of Gothenburg (Sweden) and Beijing Computational Science Research Center (China)


The two-impurity Kondo model has bearings on a number of topical problems, from heavy-fermion physics to spin-based quantum computing. In this talk I will review what is known about the model and also present a novel approach to its study, initiated in a collaboration with A. Bayat, S. Bose, and P. Sodano [1]. Specifically, we propose that real-space properties of the model can be obtained from an effective spin model where two single-impurity Kondo spin chains are joined via an RKKY interaction between the two impurity spins. We then use the Density Matrix Renormalization Group (DMRG) to study its features, using two complementary quantum-entanglement measures, the negativity and the von Neumann entropy. This nonperturbative approach enables us to uncover the Kondo screening cloud and its enhancement in the limit of large ferromagnetic RKKY coupling, thus corroborating a long-standing conjecture of ”Kondo resonance narrowing" for effectively large impurity spins. In a follow-up work [2], we extended our approach to study the entanglement spectrum of the model, and obtained the Schmidt gap, i.e. the difference between the two largest eigenvalues of the reduced density matrix. The Schmidt gap is found to signal the quantum phase transition between the Kondo and RKKY phases, in effect serving as an order parameter, correctly predicting the known scaling exponent for the Kondo crossover length at the critical point. Time permitting, I will briefly discuss also some more recent applications of our approach, to the study of local quantum quenches [3], the entanglement structure of the two-channel Kondo model [4], and impurity quantum thermodynamics [5].

 

[1] A. Bayat et al., Phys. Rev. Lett. 109, 066403 (2012)
[2] A. Bayat et al., Nat. Comm. 5, 3784 (2014)
[3] A. Bayat et al., Phys. Rev. B 92, 155141 (2015)
[4] B. Alkurtass et al., Phys. Rev. B 93, 081106(R) (2016)
[5] A. Bayat et al., Phys. Rev. B 93, 201106(R) (2016)

Contact: Heung Sun Sim, Physics Dept., (hs_sim@kaist.ac.kr)

번호 날짜 장소 제목
525 2024-03-08 11:00  E6-2 #1323  2024 봄학기 광학분야 및 응집물리 특별세미나 전체 일정 file
524 2024-02-16 10:00  E6, #1323  Optical conductivity of superconducting states driven by Van Hove singularities
523 2024-01-26 15:00  E6-2 #1323  In-situ 4D-STEM studies on surface reconstruction and polarization switching of perovskite oxides
522 2024-01-25 16:00  CAPP Seminar Room C303, Creation Hall, KAIST Munji Campus  [CAPP seminars] Detecting Gravitational Waves by Elecromagnetic Cavity
521 2024-01-24 15:00  E6-2 #1323  Determination of single molecule loading rate during mechanotransduction file
520 2024-01-16 16:00  E6-2, #2502  [High Energy Theory Seminar] Towards quantum black hole microstates
519 2024-01-16 14:00  E6-2, #1323  Dimer Physics and Superconductivity in La3Ni2O7
518 2024-01-03 11:00  E6-2, #1323  Interplay of Strong Correlations, Topology, and Disorder in 2D Quantum Matters
517 2023-12-19 16:00  E6-2, #1323  [High Energy Theory Seminar] Non-invertible symmetries, leptons, quarks, and why multiple generations
516 2023-12-14 16:00  CAPP Seminar Room C303, Creation Hall, KAIST Munji Campus  Superconducting qubits for large-scale quantum computers file
515 2023-12-08 10:30  E6-2, Rm#2502  Novel transport phenomena in insulators
514 2023-11-30 10:30  E6-2, #1322  [High-Energy Theory Seminar] 3d-3d correspondence and 2d N = (0,2) boundary conditions
513 2023-11-29 10:00  Zoom  [High Energy Theory Seminar] Averaged null energy and the renormalization group
512 2023-11-23 16:00  E6-2(Natural Science B/D). 1st fl. #1323  Deciphering the Enigma of Quantum Materials by X-ray Scattering and Spectroscopy
511 2023-11-22 16:00  E6-2, #2502  [High Energy Theory Seminar] Renormalization and the Hierarchy Problem
510 2023-11-22 10:00  E6-2, #5301 & zoom  [High Energy Theory Seminar] Exact Quantum Algorithms to Recognize Quantum Phases of Matter
509 2023-11-16 16:00  E6-2(Natural Science B/D). 1st fl. #1323  Electric-field control of emergent phenomena in correlated oxide thin films
508 2023-11-15 16:00  E6-6, #119  Quantum hydrodynamic theory for plasmonics: from molecule-coupling to nonlinear optics
507 2023-11-09 16:00  E6-2(Natural Science B/D). 1st fl. #1323  Assessing the Capability of Near-Term Photonic Devices Towards Quantum Supremacy
506 2023-11-08 10:00  E6-2,#2502 & zoom  [High Energy Theory seminar] The Vacuum Sector of Asymptotically Isometric Codes