visual
visual

세미나

  • HOME
  • >
  • 소식
  • >
  • 세미나
장소 E6-2. #2502(2nd fl.) 
일시 4pm, Sep. 21 (Wed. 
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 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
101 May 24 (Tue) 4 PM  E6-2. #1323(1st fl.)  Dr. Euyheon Hwang, SKKU Advanced Institute of Nanotechnology, Sung Kyung Kwan University  Electronic and magnetic properties of 2D transition-metal thiophosphates and tunability of magnetic order with carrier density
100 May 29 (Tue.), 04:00 PM  #1323, E6-2  Prof. Jae-Won Jang  Investigation on metal nanostructure/semiconductor junction and its applications file
99 May 30 (Thu.), 16:00 PM  #1323, E6-2  Prof. Chang-Hee Cho  Tuning the excitonic properties of semiconductors with light-matter interactions file
98 May 31 (Fri.), 11:00 AM  #1323, E6-2  Prof. Guido Burkard  Cavity QED with Spin Qubits file
97 May 31 (Tue.) 4 PM  #1323(E6-2, 1st fl.)  Dr. Kimin Kim, KAIST  Understanding 3D tokamak physics towards advanced control of toroidal plasma
96 May 311 (Thu.), 04:00 PM  #1323, E6-2  Prof. Teun-Teun Kim  Dynamic control of optical properties with gated-graphene metamaterials file
95 May. 8th (Wed), 16:00  E6 Room(#1323)  Jieun Lee  Imaging valley dependent electron transport in 2D semiconductors file
94 May 9 (Thu.), 16:00 PM  #1323, E6-2  Prof. Kwang Geol Lee  Quantum Optical Sensing Using Single Photons And Single Photon Emission from Single Emitters file
93 May 9 (Thu.), 16:00 PM  #1323, E6-2  Prof. Kwang Geol Lee  Quantum Optical Sensing Using Single Photons And Single Photon Emission from Single Emitters file
92 May 9 (Wed.), 04:00 PM  #1323, E6-2  Prof. Jong-Soo Rhyee  Recent advances in thermoelectric bulk composites file
91 May. 11 (Fri.), 02:30 PM  E6-2. 1st fl. #1323  Dr. Kun Woo Kim  Disordered Floquet topological insulators file
90 May. 11 (Fri.), 04:00 PM  E6-2. 1st fl. #1323  Dr. Nam Kim  암페어 단위 재정의와 단전자 펌프 소자 개발 file
89 May. 12 (Fri.), 01:30 PM  E6-2. 1st fl. #1323  Dr. Young Kuk Kim  Topological Dirac insulator
88 May. 17 (Thu.), 01:30 PM  E6-2. 1st fl. #1323  Prof. Yong-Baek Kim University of Toronto  Quantum Spin Liquid in Kitaev Materials file
87 May. 3 (Fri), 11:00 AM  E6-2. 2st fl. #2502  Prof. Changhee Sohn  Exotic Magnetism file
86 May. 8th (Wed), 16:00  E6 Room(#1323)  Jieun Lee  Imaging valley dependent electron transport in 2D semiconductors file
85 Nov. 04 (Fri), 1:30 PM  E6-2. #1323(1st fl.)  Dr. Jonghyun Song, Department of Physics, Chungnam National University  Exotic phenomena at oxide LaAlO3/SrTiO3 hetero-interface and their applications
84 Nov. 04 (Fri), 3:00 PM  E6-2. #1323(1st fl.)  Dr. Dohun Kim, Department of Physics and Astronomy, SNU  Quantum information experiments using few electron spins in semiconductors
83 Nov. 1 (Fri.), 02:30 PM  E6-2. 1st fl. #1323  Dr. YoungWook Kim  Squeezing the best out of 2D materials file
82 Nov. 1 (Fri.), 04:00 PM  E6-2. 1st fl. #1323  Dr. Ju-Jin Kim  Electron transport through weak-bonded contact metal with low dimensional nano-material file