Fig. 7

Time evolution of the Hurst exponent results 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 count data. A dashed horizontal line is drawn along H = 0.5 to indicate a white noise state. H < 0.5 represents data corresponding to an anti-correlated or mean-reversing state, while H > 0.5 shows persistence or long-range memory in the data. We have shown examples of the state transitions from long-range memory/persistence to random to mean-reversion using the dashed lines