Entanglement entropy and dynamical Kondo effect near Kondo Destruction Quantum Critical Point

Quantum critical metals without quasiparticles are of extensive current interest [1]. An exemplary case appears in heavy fermion metals, where the notion of Kondo destruction quantum criticality plays a central role. It goes beyond the conventional Landau order-parameter framework. Across the Kondo destruction quantum critical point, a “large” to “small” Fermi surface transformation takes place, reflecting the suppression of the Kondo singlet in the ground state [1]. However, a dynamical Kondo effect has been shown to persist, leading to a singular charge response [2,3]. An important way to characterize the dynamical Kondo effect is to use quantum entanglement properties [4,5]. Here, we study the behavior of the entanglement entropy across the Kondo destruction transitions and discuss its implications in characterizing the nature of the Kondo destruction quantum criticality.

Work supported by the NSF Grant No. DMR-2220603 and the Welch Foundation Grant No. C1-411.

[1] H. Hu, L. Chen, Q. Si, Quantum critical metals: dynamical Planckian scaling and loss of quasiparticles, arXiv:2210.14183. S. Paschen and Q. Si, Quantum phases driven by strong correlations. Nat. Phys. Rev. 3, 9 (2021). Si, Q., Rabello, S., Ingersent, K. & Smith, J. L. Locally critical quantum phase transitions in strongly correlated metals. Nature 413, 804–808 (2001).

[2] Cai, A., Yu, Z., Hu, H., Kirchner, S. & Si, Q. Dynamical Scaling of Charge and Spin Responses at a Kondo Destruction Quantum Critical Point. Phys. Rev. Lett. 124, 027205 (2020).

[3] Prochaska, L. et al. Singular charge fluctuations at a magnetic quantum critical point. Science 367, 285–288 (2020).

[4] Hu, H., Cai, A. & Si, Q. Quantum Criticality and Dynamical Kondo Effect in an SU(2) Anderson Lattice Model. arXiv:2004.04679 [cond-mat] (2020).

[5] Mahankali, M., Si, Q. unpublished (2022).