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Entanglement in a second order quantum phase transition

J. Vidal·G. Palacios·R. Mosseri
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Abstract

We consider a system of mutually interacting spin 1/2 embedded in a transverse magnetic field which undergo a second order quantum phase transition. We analyze the entanglement properties and the spin squeezing of the ground state and show that, contrarily to the one-dimensional case, a cusp-like singularity appears at the critical point $λ_c$, in the thermodynamic limit. We also show that there exists a value $λ_0 \geq λ_c$ above which the ground state is not spin squeezed despite a nonvanishing concurrence.

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J. Vidal, G. Palacios, R. Mosseri. 2003-12-02. Entanglement in a second order quantum phase transition. https://doi.org/10.1103/physreva.69.022107

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