Fig. 6: Entanglement entropy dynamics.
Real-time evolution of entanglement entropy (blue line) and comparison with the associated thermal entropy (red dashed line) for (a) the k = 0 momentum basis state corresponding to β = 0.005, closest to the spectral mean energy and b the strong coupling ground state for a subsystem of length NA = 3 on the periodic nine-plaquette chain with \({j}_{\max }=1\) and ag2 = 1.2 in the zero-momentum and reflection symmetric sector. The entanglement entropy growth as a function of time is fitted to the two-parameter function in Eq.(10) (pink dotted line), where we find (a) κ = 0.616 ± 0.003, \(\log ({t}_{0})=0.097\pm 0.004\) and b κ = 0.608 ± 0.014, \(\log ({t}_{0})=-0.555\pm 0.021\). The orange region in (b) corresponds to the thermal entanglement entropy of the 1σ-band associated with the energy variance of the strong coupling ground state.
