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arXiv · 2308.16204

Four interacting spins: addition of angular momenta, spin-spin correlation functions, and entanglement

Raimundo R. dos Santos·Lucas Alves Oliveira·Natanael C. Costa
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Abstract

We study four spins on a ring coupled through competing Heisenberg interactions between nearest neighbors, $J$, and next-nearest neighbors, $J_2\equiv\alpha J>0$. The spectrum is obtained in a simple way by using the rules for addition of 4 angular momenta. This allows us to follow the evolution of the ground state with $\alpha$, characterized by level crossings and by analyses of spin-spin correlation functions. Further insight is obtained by examining the entanglement between different parts of the system: we observe that the entanglement entropy is strongly dependent on how the system is partitioned.

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Raimundo R. dos Santos, Lucas Alves Oliveira, Natanael C. Costa. 2023-08-29. Four interacting spins: addition of angular momenta, spin-spin correlation functions, and entanglement. https://doi.org/10.1119/5.0150433

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