Emergent family of Tsallis entropies from the $q$-deformed combinatorics

TL;DR

This paper derives an exact, smooth formula for the $q$-generalized multinomial coefficient using $q$-deformed algebra, revealing a new family of Tsallis entropies and symmetries across all real $q$ values.

Contribution

It introduces a novel, exact formula for $q$-multinomial coefficients via $q$-deformed combinatorics, involving infinite series and analytic continuation, advancing the understanding of Tsallis entropy.

Findings

Exact formula valid for all real $q$

Revealed symmetry linking different $q$ values

Connected $q$-deformed factorials with Riemann zeta function

Abstract

We revisit the derivation of a formula for the $q$-generalised multinomial coefficient rooted in the $q$-deformed algebra, a foundational framework in the study of nonextensive statistics. Previous approximate expressions in the literature diverge as $q$ approaches 2 (or 0, depending on convention). In contrast, our derived formula provides an exact, smooth function for all real values of $q$, expressed as an infinite series expansion involving Tsallis entropies with sequential entropic indices, coupled with Bernoulli numbers. This formulation is achieved through the analytic continuation of the Riemann zeta function, stemming from the $q$-deformed factorials. Our formula thus offers a distinctive characterisation of Tsallis entropy within the $q$-deformed combinatorics. Throughout this exploration, we also highlight a symmetry within the $q$-deformed theory that links different values of the entropic parameter. Furthermore, we discuss extending our results to encompass more general, affinity-sensitive cases, building on the previously established framework of affinity-based extended entropy.