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Comment on ``Lyapunov Exponent of a Many Body System and Its Transport Coefficients''

A. Torcini·Ch. Dellago·H. A. Posch
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Abstract

In a recent Letter, Barnett, Tajima, Nishihara, Ueshima and Furukawa obtained a theoretical expression for the maximum Lyapunov exponent $λ_1$ of a dilute gas. They conclude that $λ_1$ is proportional to the cube root of the self-diffusion coefficient $D$, independent of the range of the interaction potential. They validate their conjecture with numerical data for a dense one-component plasma, a system with long-range forces. We claim that their result is highly non-generic. We show in the following that it does not apply to a gas of hard spheres, neither in the dilute nor in the dense phase.

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A. Torcini, Ch. Dellago, H. A. Posch. 1999-04-21. Comment on ``Lyapunov Exponent of a Many Body System and Its Transport Coefficients''. https://doi.org/10.1103/physrevlett.83.2676

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