Multipartite entanglement and quantum criticality in Kondo lattice systems

Metallic quantum critical states without quasiparticles invoke extensive current interest. A salient example appearing in the Kondo systems is associated with the notion of Kondo destruction, which leads to a loss of quasiparticle everywhere on the Fermi surface [1]. At this quantum critical point (QCP), both the spin and charge responses are singular and obey dynamical Planckian scaling, with a large amount of entropy in the quantum fluctuation spectrum [2]. Developing protocols to detect and quantify the entanglement may help characterize both the quantum phases and criticality. Here [3], we show that the quantum Fisher information (QFI), representing a witness for the multipartite entanglement, is an ideal tool for this purpose. We study the behavior of the QFI across the Kondo destruction transition and discuss its implications in charactering the Kondo destruction QCP.





[1] H. Hu, L. Chen, Q. Si, arXiv:2210.14183; Q. Si et al, Nature 413, 804 (2001)



[2] L. Prochaska et al., Science 367, 285–288 (2020); A. Cai et al., Phys. Rev. Lett. 124, 027205 (2020)



[3] Y. Fang, L. Chen, Y. Wang, M. Mahankali, Q. Si, unpublished (2023)