Behaviors of thermalization for the Fermi–Pasta–Ulam–Tsingou system with small number of particles |
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作者单位: | College of Science, Hohai University, Nanjing 210098, China |
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基金项目: | Project supported by the Fundamental Research Funds for the Central Universities, China (Grant Nos. 2017B17114 and B210202152). |
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摘 要: | We study the behaviors of thermalization in Fermi–Pasta–Ulam–Tsingou(FPUT) system with small number of particles using periodic boundary conditions. The total energy has initially equidistributed among some of the lowest frequency modes. The thermalization time t_(eq) depending on system's energy density ε scales as t_(eq) ∝ε~(-4) only within a certain range of nonlinearity. In this range of nonlinearity, energies can interchange between the initial excited modes and other modes continuously with time until reaching the thermalized state. With a further decreasing nonlinearity, a steeper growth than ε~(-4) will appear. In the very weakly nonlinear regime, energies on low frequency modes are found to be frozen on large time scales. Redistribution of mode energies happens through the resonances of high frequency modes.
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收稿时间: | 2020-11-28 |
Behaviors of thermalization for the Fermi-Pasta-Ulam-Tsingou system with small number of particles |
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Institution: | College of Science, Hohai University, Nanjing 210098, China |
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Abstract: | We study the behaviors of thermalization in Fermi-Pasta-Ulam-Tsingou (FPUT) system with small number of particles using periodic boundary conditions. The total energy has initially equidistributed among some of the lowest frequency modes. The thermalization time teq depending on system's energy density ε scales as teq ∝ ε-4 only within a certain range of nonlinearity. In this range of nonlinearity, energies can interchange between the initial excited modes and other modes continuously with time until reaching the thermalized state. With a further decreasing nonlinearity, a steeper growth than ε-4 will appear. In the very weakly nonlinear regime, energies on low frequency modes are found to be frozen on large time scales. Redistribution of mode energies happens through the resonances of high frequency modes. |
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Keywords: | FPUT system thermalization small number of particles |
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