The system of N particles moving on a circle and interacting via a global repulsive cosine interaction is well known to display spatially inhomogeneous structures of extraordinary stability starting from certain low-energy initial conditions. The aim of this paper is to show in a detailed manner how these structures arise and to explain their stability. By a convenient canonical transformation we rewrite the Hamiltonian in such a way that fast and slow variables are singled out and the canonical coordinates of a collective mode are naturally introduced. If, initially, enough energy is put in this mode, its decay can be extremely slow. However, both analytical arguments and numerical simulations suggest that these structures eventually decay to the spatially uniform equilibrium state, although this can happen on impressively long time scales. Finally, we heuristically introduce a one-particle time-dependent Hamiltonian that well reproduces most of the observed phenomenology.

Inhomogeneous quasi-stationary states in a mean-field model with repulsive cosine interactions / Leyvraz, F.; Firpo, M. C.; Ruffo, S.. - In: JOURNAL OF PHYSICS. A, MATHEMATICAL AND GENERAL. - ISSN 0305-4470. - 35:20(2002), pp. 4413-4427. [10.1088/0305-4470/35/20/303]

Inhomogeneous quasi-stationary states in a mean-field model with repulsive cosine interactions

Ruffo, S.
2002-01-01

Abstract

The system of N particles moving on a circle and interacting via a global repulsive cosine interaction is well known to display spatially inhomogeneous structures of extraordinary stability starting from certain low-energy initial conditions. The aim of this paper is to show in a detailed manner how these structures arise and to explain their stability. By a convenient canonical transformation we rewrite the Hamiltonian in such a way that fast and slow variables are singled out and the canonical coordinates of a collective mode are naturally introduced. If, initially, enough energy is put in this mode, its decay can be extremely slow. However, both analytical arguments and numerical simulations suggest that these structures eventually decay to the spatially uniform equilibrium state, although this can happen on impressively long time scales. Finally, we heuristically introduce a one-particle time-dependent Hamiltonian that well reproduces most of the observed phenomenology.
2002
35
20
4413
4427
PII S0305-4470(02)30568-7
Leyvraz, F.; Firpo, M. C.; Ruffo, S.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11767/14270
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