Indicators of spin coherence and the degree of entanglement averaged over the Fermi energy versus the spin–orbit coupling strength. (a)–(d) Averaged magnitude of the polarization vector 〈 | P | 〉 ε f and (e)–(h) averaged van Neumann entropy S versus the normalized value t_so of spin–orbit interaction strength for four different intervals of energy averaging: [0.016, 0.0624], [0.0632, 0.140], [0.1408, 0.2472], and [0.248, 0.3816], corresponding to regimes with one to four transmission modes, respectively. In each panel, the five dot-dashed curves are for mixed dynamics while the four solid curves correspond to chaotic dynamics.