Entropic properties of $D$-dimensional Rydberg systems

TL;DR

This paper analytically computes the entropic measures of highly-excited Rydberg states in D-dimensional hydrogenic systems, revealing their dependence on system parameters through asymptotic analysis of Laguerre polynomials.

Contribution

It provides the first analytical determination of Rènyi and Tsallis entropies for Rydberg states in arbitrary dimensions using asymptotics of Laguerre polynomials.

Findings

Explicit formulas for entropic measures in high quantum number limit

Dependence of entropies on dimensionality and quantum numbers

Numerical validation of analytical results

Abstract

The fundamental information-theoretic measures (the R\'enyi $R_{p}[\rho]$ and Tsallis $T_{p}[\rho]$ entropies, $p>0$) of the highly-excited (Rydberg) quantum states of the $D$-dimensional ($D>1$) hydrogenic systems, which include the Shannon entropy ($p \to 1$) and the disequilibrium ($p = 2$), are analytically determined by use of the strong asymptotics of the Laguerre orthogonal polynomials which control the wavefunctions of these states. We first realize that these quantities are derived from the entropic moments of the quantum-mechanical probability $\rho(\vec{r})$ densities associated to the Rydberg hydrogenic wavefunctions $\Psi_{n,l,\{\mu\}}(\vec{r})$, which are closely connected to the $\mathfrak{L}_{p}$-norms of the associated Laguerre polynomials. Then, we determine the ($n\to\infty$)-asymptotics of these norms in terms of the basic parameters of our system (the dimensionality $D$, the nuclear charge and the hyperquantum numbers $(n,l,\{\mu\}$) of the state) by use of recent techniques of approximation theory. Finally, these three entropic quantities are analytically and numerically discussed in terms of the basic parameters of the system for various particular states.