Correlation transfer in large-spin chains

It is shown that transient spin-spin correlations in a one-dimensional spin $S\gg 1$ chain can be enhanced for initially factorized and individually squeezed spin states. Such correlation transfer from “internal” to “external” degrees of freedom can be well described by using a semiclassical phase-space approach.

Figure 1

The evolution of the $C_{I_j},j\ne 1,6$ in the chain of 6 spin of size $S=5$. The upper curve corresponds to the optimum squeezing case with ${\mu }_{\mathrm{opt}}=0.5$ and $\vartheta =0.2645$. The middle curve represents the nonsqueezed initial spin coherent state. The lowest curve is $C_{I_j}$ for $S=1/2$. Exact calculations are represented by solid lines and the semiclassical approximation by dot-dashed lines.

Figure 2

The evolution of the $C_{I_N}$ in the chain of 6 spin of size $S=5$. The upper curve corresponds to the optimum squeezing case with ${\mu }_{\mathrm{opt}}=0.5$ and $\vartheta =0.2643$. The middle curve represents the nonsqueezed initial spin coherent state. The lowest curve is $C_{I_N}$ for $S=1/2$. Exact calculations are represented by solid lines and the semiclassical approximation by dot-dashed lines.

Figure 3

The evolution of ${\mathcal{N}}_{j,j+1}$ for an internal pair $(j\ne 1,6)$, $N=7$, $S=7$. The upper curve corresponds to the optimum squeezing case with ${\mu }_{\mathrm{opt}}\approx 0.856S^{-0.72}$; the lower curve represent the evolution without squeezing: solid lines (exact calculations), dot-dashed lines [the semiclassical approximation (17)].

Figure 4

The evolution of ${\mathcal{N}}_{1,2}$, $N=7$, $S=7$. The upper curve corresponds to the optimum squeezing case with ${\mu }_{\mathrm{opt}}\approx 0.856S^{-0.72}$; the lower curve represent the evolution without squeezing: solid lines (exact calculations), dot-dashed lines [the semiclassical approximation (17)].

Figure 5

The exact Wigner function of the initial $j\text{th}$ spin state $|{\psi }_0{\rangle }_j$ in Eq. (2).