Beyond local detailed balance: Microscopic rates reshape nonequilibrium phase behavior

Takahiro Kanazawa; Kyogo Kawaguchi; Kyosuke Adachi

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arXiv · 2605.25406

Beyond local detailed balance: Microscopic rates reshape nonequilibrium phase behavior

Takahiro Kanazawa·Kyogo Kawaguchi·Kyosuke Adachi

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Abstract

Local detailed balance (LDB) is a central guiding principle for modeling nonequilibrium stochastic dynamics, yet it only constrains the ratio of forward and backward transition rates and does not fix the steady state. Although the functional form of rates under the same LDB has been shown to affect steady-state correlations and transition temperatures, whether it can qualitatively reshape phase behavior in strongly interacting systems, such as the morphology and stability of phase-separated patterns, remains unclear. Here, for a two-dimensional driven lattice gas with attractive nearest-neighbor interactions, we consider hopping rates with a parameter that preserves the same LDB but tunes asymmetry along the driving force. We find that this parameter controls qualitative phase behavior: in the homogeneous phase, it reverses the sign of the structure-factor discontinuity and hence the anisotropy in long-range density correlations; in the phase-separated regime, it switches the orientation of anisotropic patterns and their long-time stability. Both effects are coherently captured by an approximate fluctuating hydrodynamic equation. The results demonstrate that, in contrast to equilibrium systems, qualitative features of nonequilibrium phases are controlled by the specific choice of dynamical rules even under the same LDB.

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Takahiro Kanazawa, Kyogo Kawaguchi, Kyosuke Adachi. 2026-05-25. Beyond local detailed balance: Microscopic rates reshape nonequilibrium phase behavior. https://arxiv.org/abs/2605.25406

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