Trends in Gibbs States for Thermodynamics of Canonical Nonlinearity

Ryu Tomitaka; Koretaka Yuge

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arXiv · 2505.05674

Trends in Gibbs States for Thermodynamics of Canonical Nonlinearity

Ryu Tomitaka·Koretaka Yuge

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Abstract

When we consider canonical average for classical discrete systems under constant composition (specifically, substitutional alloys) as a map phi from a set of many-body interatomic interactions to that of microscopic configuration in thermodynamic equilibrium, phi generally exhibits complicated nonlinearity. The nonlinearity has recently been amply studied in terms of configurational geometry, measured by vector field and Kullback-Leibler divergence, whose individual concepts are further unified through stochastic thermodynamic transformation: We call this procedure as Themodynamics of canonical nonlinearity (TCN). Although TCN can reveal the non-linear character across multiple configurations through thermodynamic functions, the essential role for Gibbs states (GBS) in terms of the nonlinearity is still totally unclear. We here tackle this problem, and reveal the characteristic roles of the GBS: (i) Concrete expression of the GBS is derived, (ii) strong correlation between GBSs and averaged nonlinearity over configurations for moled systems is found, and (iii) GBS-based bounds for averaged nonlinearity at specific conditions is derived.

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Ryu Tomitaka, Koretaka Yuge. 2025-05-08. Trends in Gibbs States for Thermodynamics of Canonical Nonlinearity. https://arxiv.org/abs/2505.05674

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