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
164 2016-07-08 11:00  #1323(E6-2. 1st fl.)  Isostatic magnetism
163 2016-05-19 15:00  May 19, 2016 (Thur.) 3PM,  The CERN Resonant WISP Search: Development, Results and Lesson-Learned
162 2023-06-22 16:00  CAPP Seminar Room C303, Creation Hall, KAIST Munji Campus  [CAPP Seminar] The muon g-2 puzzle file
161 2015-10-15 10:00  E6-2, 5th fl. #5318  Development of Large-Bore, High Field Magnets at the NHMFL
160 2017-03-24 14:30  #1323 (1st fl. E6-2).  Topological Dynamics
159 2018-10-26 16:00  #1323, E6-2  Coexisting triple-point and nodal-line topological magnons and thermal Hall effect in pyrochlore iridates file
158 2015-07-16 16:00  E6-2, 1318  Next-generation ultrafast laser technology for nonlinear optics and strong-field physics
157 2023-04-27 11:00  E6-2 #1322  Inverse Shapiro steps and coherent quantum phase slip in superconducting nanowires
156 2022-08-18 10:00  E6-1 #1323  Disorder-driven phase transition in the second-order non-Hermitian skin effect
155 2018-11-01 16:00  #1323, E6-2  Direct holography from a single snapshot file
154 2016-03-11 13:30  E6-2. 1st fl. #1501  Topological phases of matter in nonequilibrium: Topology of the Wannier-Stark ladder
153 2015-12-11 13:30  E6-2, #1323  Quantum spin liquid in the 1/3 depleted triangular lattice Ba3(Ru1-xIrx)Ti2O9
152 2021-07-29 14:00  Online seminar  Gravitationally Induced Dark Sector and Inflationary Dynamics file
151 2022-05-13 14:30  Zoom webinar  Topological Superconducting Spintronics Towards Zero-Power Computing Technologies file
150 2016-12-09 16:00  #1323(E6-2. 1st fl.  Shift Charge and Spin Photocurrents in Dirac Surface States of Topological Insulator
149 2018-05-11 14:30  E6-2. 1st fl. #1323  Disordered Floquet topological insulators file
148 2023-09-14 16:00  CAPP Seminar Room C303, Creation Hall, KAIST Munji Campus  [CAPP seminar] Dark matter searches in Water Cherenkov Detectors file
147 2024-06-13 16:00  E6-2, #1323  Magnonic $\varphi$ Josephson junction and its non-Hermitian Josephson diode effect
146 2023-07-18 11:00  E6-2, #1323  Non-Hermitian Casimir Effect of Magnons
145 2016-05-31 16:00  #1323(E6-2, 1st fl.)  Understanding 3D tokamak physics towards advanced control of toroidal plasma