Fig. 8

Time evolution of the scaling exponent, α, calculated from the Detrended Fluctuation Analysis (DFA) for all twelve countries’ daily infection and death log return time series: (a) The top panel shows the time evolution from TW1-TW2-TW3 for the log return infection data; (b) the bottom panel shows the time evolution from TW1-TW2-TW3 for the log return death data. A horizontal dashed line shows α = 0.5 to indicate a white noise state. We have shown examples of the state transitions from long-range memory/persistence to random to mean-reversion using the dashed lines