Fluctuation--Response Relation in Finite-Size Noisy Coupled Phase Oscillators
Abstract
Fluctuation--response relations (FRRs) provide a fundamental relation between spontaneous fluctuations and the linear response to external perturbations, yet their validity in non-equilibrium systems remains an open problem. In a general class of noisy, finite-size, mean-field models of coupled phase oscillators, we reveal two types of FRRs in the incoherent phase below the synchronization transition. The first, corresponding to the infinite-size limit (I-FRR), involves the convolution between the external force and the correlation function in the time domain. The second, the finite-size counterpart (F-FRR), is governed by finite-size fluctuations and carries a correction factor: a spectrum function whose roots correspond to eigenvalues, or Landau poles, of the linear operator. The finite-size fluctuations are suppressed in the weak-coupling or strong-noise limits, and F-FRR reduces to I-FRR. Our analytical findings are verified by extensive numerical simulations.
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BibTeX
@misc{sarkar2026fluctuationresponse,
title = {{Fluctuation--Response Relation in Finite-Size Noisy Coupled Phase Oscillators}},
author = {Mrinal Sarkar and Yoshiyuki Y. Yamaguchi},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.28834},
eprint = {2609.28834},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.28834},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Fluctuation--Response Relation in Finite-Size Noisy Coupled Phase Oscillators
AU - Mrinal Sarkar
AU - Yoshiyuki Y. Yamaguchi
PY - 2026
DA - 2026/09/23
PB - arXiv
DO - 10.48550/arxiv.2609.28834
UR - https://arxiv.org/abs/2609.28834
AB - Fluctuation--response relations (FRRs) provide a fundamental relation between spontaneous fluctuations and the linear response to external perturbations, yet their validity in non-equilibrium systems remains an open problem. In a general class of noisy, finite-size, mean-field models of coupled phase oscillators, we reveal two types of FRRs in the incoherent phase below the synchronization transition. The first, corresponding to the infinite-size limit (I-FRR), involves the convolution between the external force and the correlation function in the time domain. The second, the finite-size counterpart (F-FRR), is governed by finite-size fluctuations and carries a correction factor: a spectrum function whose roots correspond to eigenvalues, or Landau poles, of the linear operator. The finite-size fluctuations are suppressed in the weak-coupling or strong-noise limits, and F-FRR reduces to I-FRR. Our analytical findings are verified by extensive numerical simulations.
ER -