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
269 2019-10-29 16:00  #1323 (E6-2, 1st fl.)  Particles and Gravity via String Geometry file
268 2019-10-29 14:30  #1323, E6-2  Quantum sensing file
267 2019-10-29 10:00  #1323 (E6-2, 1st fl.)  Unconventional Spin Transport in Quantum Materials file
266 2019-10-25 15:00  #1323, E6-2  Physics Seminar file
265 2019-10-17 16:00  #1323, E6-2  Top down manipulation of Waves : From Metamaterials, Correlated Disorder, Quantum Analogy, to Digital Processing file
264 2019-10-16 16:00  #1323 (E6-2, 1st fl.)  Emergent black holes and monopoles from quantum fields file
263 2019-10-15 16:00  #1323, E6-2  Moiré superlattices and graphene quasicrystal file
262 2019-09-27 16:00  E6-2. 1st fl. #1323  0D/1D/2D/3D III-V materials grown by MBE for Optelectronics file
261 2019-09-27 14:30  E6-2. 1st fl. #1323  Spin-charge conversion in topological insulators for spintronic applications file
260 2019-09-26 16:00  #1323, E6-2  Entanglement Swapping with Autonomous Polarization-Entangled Photon-Pairs from Warm Atomic Ensemble file
259 2019-09-18 16:00  #1323, E6-2  Exploring Synthetic Quantum Matter in Superconducting Circuits file
258 2019-09-18 16:00  Seminar Room #1323  Fall 2019: Physics Seminar Serises file
257 2019-09-10 15:00  E6-2. 1st fl. #1323  Two-Stage Kondo Effect file
256 2019-09-10 15:00  #2502, E6-2  (2+1) D Duality Web from 3D Euclidean Lattice file
255 2019-09-02 16:00  Seminar Room 1501  Fall 2019: Physics Colloquium file
254 2019-08-27 16:00  Rm. 1323, E6  Critical current properties of Fe-based superconductors file
253 2019-08-22 16:00  #1323, E6-2  Physics and Applications in Nanoelectronics and Nonomechanics file
252 2019-08-19 10:00  Rm. 1322, E6-2  Tutorials on Multimode Quantum Optics in the Continuous Variable Regime file
251 2019-08-16 14:00  E6 Room(#1323)  Multiferroic and Magnetoelectric Effects by Tailoring Interfacial Chemistry and Physics in Correlated Oxides file
250 2019-08-14 16:00  Rm. 1323, E6  Quantum Optics, at the heart of quantum metrology and quantum information file