Entanglement Spectrum in Cluster Dynamical Mean-Field Theory

TL;DR

This paper investigates the entanglement spectrum of the kagome Hubbard model using cluster dynamical mean-field theory, revealing temperature-dependent features linked to chiral degrees of freedom and magnetic correlations.

Contribution

It introduces a method to compute the entanglement spectrum within cluster DMFT and uncovers its temperature-dependent behavior in a kagome lattice system.

Findings

Identification of a characteristic temperature T_{chiral} for chiral eigenvalues

Observation of large quasiparticle mass in the metallic state below T_{chiral}

Development of inter-triangular ferromagnetic correlations in the metallic regime

Abstract

We study the entanglement spectrum of the Hubbard model at half filling on a kagome lattice. The entanglement spectrum is defined by the set of eigenvalues of reduced thermal density matrix, which is naturally obtained in the framework of the dynamical mean-field theory. Adopting the cluster dynamical mean-field theory combined with continuous-time auxiliary-field Monte Carlo method, we calculate the entanglement spectrum for a three-site triangular cluster in the kagome Hubbard model. We find that the results at the three-particle sector well captures the qualitative nature of the system. In particular, the eigenvalue of the reduced density matrix, corresponding to the chiral degrees of freedom, exhibits characteristic temperature scale T_{\rm chiral}, below which a metallic state with large quasiparticle mass is stabilized. The entanglement spectra at different particle number sectors also exhibit characteristic changes around T_{\rm chiral}, implying the development of inter-triangular ferromagnetic correlations in the correlated metallic regime.