Interplay between charge and spin thermal entanglement in Hubbard dimers
Fabiana Souza, G. M. A. Almeida, M. L. Lyra +1 more
We study quantum entanglement in half-filled Hubbard dimers at finite temperatures under an external magnetic field. Due to the itinerant nature of the electrons and their fundamental indistinguishability, we employ a site-based evaluation of entanglement via the concurrence in three distinct sectors of the Hilbert space, namely the charge, zero-, and single-spin subspaces. At zero temperature these measures can be combined to produce an accurate estimate of the entanglement entropy. For finite temperatures we show that those concurrences display reentrant behavior upon varying the magnetic field. Furthermore, we unveil that charge and spin quantum correlations are quite distinctly degraded by thermal fluctuations.
Physical Review A•Sep 29, 2020•12 citations