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arXiv · 2506.19018

Nonequilibrium Theory for Adaptive Systems in Varying Environments

Ying-Jen Yang·Charles D. Kocher·Ken A. Dill
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Abstract

Biological organisms are adaptive, able to function in unpredictably changing environments. Drawing on recent nonequilibrium physics, we show that in adaptation, fitness has two components parameterized by observable coordinates: a static Generalism component characterized by state distributions, and a dynamic Tracking component sustained by nonequilibrium fluxes. Our findings: (1) General Theory: We prove that tracking gain scales strictly with environmental variability and switching time-scales; near-static or fast-switching environments are not worth tracking. (2) Optimal Strategies: We explain optimal bet-hedging and phenotypic memory as the interplay between these components. (3) Control: We demonstrate, with an example, how to suppress pathogens by independently attacking their Generalism robustness (via environmental time fractions) and Tracking capabilities (via environmental switching speed). This work provides a physical framework for understanding and controlling adaptivity.

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Ying-Jen Yang, Charles D. Kocher, Ken A. Dill. 2025-06-23. Nonequilibrium Theory for Adaptive Systems in Varying Environments. https://arxiv.org/abs/2506.19018

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