Entanglement in XYZ model on a spin-star system: Anisotropy vs.
field-induced dynamics
- URL: http://arxiv.org/abs/2307.15949v1
- Date: Sat, 29 Jul 2023 10:13:39 GMT
- Title: Entanglement in XYZ model on a spin-star system: Anisotropy vs.
field-induced dynamics
- Authors: Jithin G. Krishnan, Harikrishnan K. J., Amit Kumar Pal
- Abstract summary: We show that for vanishing $xy$-anisotropy $gamma$, bipartite entanglement on the peripheral spins exhibits a logarithmic growth with $n_p$.
When the system is taken out of equilibrium by the introduction of a magnetic field of constant strength on all spins, the time-averaged bipartite entanglement on the periphery exhibits a logarithmic growth with $n_p$ irrespective of the value of $gamma$.
- Score: 0.0
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: We consider a star-network of $n=n_0+n_p$ spin-$\frac{1}{2}$ particles, where
interaction between $n_0$ central spins and $n_p$ peripheral spins are of the
XYZ-type. In the limit $n_0/n_p\ll 1$, we show that for odd $n$, the ground
state is doubly degenerate, while for even $n$, the energy gap becomes
negligible when $n$ is large, inducing an \emph{effective} double degeneracy.
In the same limit, we show that for vanishing $xy$-anisotropy $\gamma$,
bipartite entanglement on the peripheral spins computed using either a partial
trace-based, or a measurement-based approach exhibits a logarithmic growth with
$n_p$, where the sizes of the partitions are typically $\sim n_p/2$. This
feature disappears for $\gamma\neq 0$, which we refer to as the
\emph{anisotropy effect}. Interestingly, when the system is taken out of
equilibrium by the introduction of a magnetic field of constant strength on all
spins, the time-averaged bipartite entanglement on the periphery at the
long-time limit exhibits a logarithmic growth with $n_p$ irrespective of the
value of $\gamma$. We further study the $n_0/n_p\gg 1$ and $n_0/n_p\rightarrow
1$ limits of the model, and show that the behaviour of bipartite peripheral
entanglement is qualitatively different from that of the $n_0/n_p\ll 1$ limit.
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