Thermal transport characteristics of Fermi-Pasta-Ulam chains undergoing\n soft-sphere type collisions

2020/06/23 by Sankhadeep Bhattacharyya, Bhattacharyya, Sankhadeep, Puneet Kumar Patra +1
Engineering · Physics and Astronomy · #Adhesion, Friction, and Surface Interactions #Advanced Fiber Optic Sensors #FOS: Physical sciences #Nonlinear Photonic Systems #Statistical Mechanics (cond-mat.stat-mech)

paper · pdf · doi:10.48550/arxiv.2006.13238

openalex publication_date 2020/06/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We show numerically that including soft-sphere type collisions in the\ncelebrated Fermi-Pasta-Ulam (FPU) chain completely alters the thermal\ntransport characteristics. The resulting FPU^C chains, while being momentum\npreserving, satisfy the Fourier's law and do not show anomalous thermal\ntransport behavior. Collisions play a significant role in reducing the boundary\njumps typically observed in FPU chains. The thermal conductivity of the\nFPU^C chains is significantly smaller than the FPU chains at low\ntemperatures due to the fast redistribution of energy from the lowest mode of\nvibrations to the higher modes. At high temperatures, however, the FPU^C\nchains have larger thermal conductivity than the FPU chains due to the large\ncontributions to the heat flux because of the large-magnitude short-ranged\nanharmonic collision force.\n

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