| We study Lyapunov spectra of spatially extended systems with symplectic symmetry in the spatial continuum limit, Δx → 0, by means of Langevin-type equations with colored noise. We find that, while the exponents corresponding to the most expanding and contracting directions converge to some finite values, the additional exponents are introduced into the spectrum around zero exponent. This leads to the appearance of an accumulation in the spectral density near zero that diverges in the continuum limit. The results are compared with data obtained for the forced nonlinear Schrödinger equation. |
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