Quantum coherence stabilization in biology via feedback with coherent background fields

Living systems operate far from thermodynamic equilibrium while maintaining a high degree of internal order, raising the long-standing question of how fragile quantum coherence can persist in warm, noisy biological environments. While several biological processes exhibit signatures of quantum coherence, the physical mechanisms responsible for stabilizing such coherence remain an active area of debate. In this work, we present a phenomenological model demonstrating that quantum coherence in open spin systems can be stabilized through entropy-dependent feedback with a weakly coupled coherent field. We consider an open quantum spin ensemble subject to environmental decoherence, augmented by (i) entropy-sensitive suppression of decoherence and (ii) a coherence-inducing interaction that favors low-entropy, collectively coherent configurations. Using multipartite Greenberger-Horne-Zeilinger (GHZ) states as representative low-entropy coherent states, numerical simulations reveal nonlinear threshold behavior, entropy collapse, and long-lived coherence despite strong environmental noise. These features provide clear signatures of a positive feedback loop, wherein coherence suppresses decoherence, reduced decoherence enhances coherence, and the resulting self-reinforcement stabilizes the system. Importantly, the model is agnostic to the physical origin of the coherent field and is compatible with a wide range of candidates, including internally generated biological oscillations, collective electromagnetic or redox dynamics, oxygen-mediated spin correlations, and other structured cellular fields. As an illustrative example, we discuss the potential role of an ultralight dark matter (ULDM) background field, whose predicted macroscopic coherence and oscillation frequencies could, in principle, participate in the same feedback mechanism. By separating the general principle of feedback-stabilized coherence from any specific physical realization, this work provides a unifying theoretical framework for understanding how quantum coherence may persist in open, noisy systems relevant to biological physics. The results suggest that coherence in living matter may arise not from isolation from the environment, but from structured coupling to coherent fields that dynamically regulate decoherence through entropy-sensitive feedback.