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Rényi and Tsallis entropies of the Dirichlet and Neumann one-dimensional quantum wells

A comparative analysis of the Dirichlet and Neumann boundary conditions (BCs) of the one-dimensional (1D) quantum well extracts similarities and differences of the Rényi $R(α)$ as well as Tsallis $T(α)$ entropies between these two geometries. It is shown, in particular, that for either BC the dependencies of the Rényi position components on the parameter $α$ are the same for all orbitals but the lowest Neumann one for which the corresponding functional $R$ is not influenced by the variation of $α$. Lower limit $α_{TH}$ of the semi infinite range of the dimensionless Rényi/Tsallis coefficient where {\em momentum} entropies exist crucially depends on the {\em position} BC and is equal to one quarter for the Dirichlet requirement and one half for the Neumann one. At $α$ approaching this critical value, the corresponding momentum functionals do diverge. The gap between the thresholds $α_{TH}$ of the two BCs causes different behavior of the Rényi uncertainty relations as functions of $α$. For both configurations, the lowest-energy level at $α=1/2$ does saturate either type of the entropic inequality thus confirming an earlier surmise about it. It is also conjectured that the threshold $α_{TH}$ of one half is characteristic of any 1D non-Dirichlet system. Other properties are discussed and analyzed from the mathematical and physical points of view.