Entanglement structure of the two-channel Kondo model Academic Article uri icon

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  • Two electronic channels competing to screen a single impurity spin, as in the two-channel Kondo model, are expected to generate a ground state with nontrivial entanglement structure. We exploit a spin-chain representation of the two-channel Kondo model to probe the ground-state block entropy, negativity, tangle, and Schmidt gap, using a density matrix renormalization group approach. In the presence of symmetric coupling to the two channels we confirm field-theory predictions for the boundary entropy difference, $\ln (g_{UV}/g_{IR})=\ln(2)/2$, between the ultraviolet and infrared limits and the leading $\ln(x)/x$ impurity correction to the block entropy. The impurity entanglement, $S_{\text{imp}}$, is shown to scale with the characteristic length $\xi_{2CK}$. We show that both the Schmidt gap and the entanglement of the impurity with one of the channels $-$ as measured by the negativity$-$ faithfully serve as order parameters for the impurity quantum phase transition appearing as a function of channel asymmetry, allowing for explicit determination of critical exponents, $\nu\!\approx\! 2$ and $\beta \!\approx\! 0.2$. Remarkably, we find the emergence of tripartite entanglement only in the vicinity of the critical channel-symmetric point.


  • Alkurtass, Bedoor
  • Bayat, Abolfazl
  • Affleck, Ian
  • Bose, Sougato
  • Johannesson, Henrik
  • Sodano, Pasquale
  • Sorensen, Erik
  • Le Hur, Karyn

publication date

  • February 18, 2016