Figure 4

Multi-level state distribution under different parameters. (a) Two-level cell with \(\alpha\) in [2, 10] and \(\sigma ^*\) in \([20\%,100\%]\). (b) Three-level cell with \(\alpha\) in [5, 20] and \(\sigma ^*\) in \([15\%,65\%]\). (c) Four-level cell with \(\alpha\) in [5, 20] and \(\sigma ^*\) in \([10\%,50\%]\). (d) Eight-level cell with \(\alpha\) in [10, 40] and \(\sigma ^*\) in \([5\%,20\%]\). e, Cumulative distribution function (CDF) of the states for configurations marked with a \(\dagger\) in (a–d) (in the right-top corners). In all cases, the optimal thresholds between states are marked with dashed vertical lines, and for a given configuration of n, \(\alpha\) and \(\sigma ^*\), the top part uses ReBE and the bottom part RatioBE (on a grey background).