02-489 Tulio O. Carvalho and Cesar R. de Oliveira
Critical energies in random palindrome models (540K, ps) Nov 26, 02
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Abstract. We investigate the occurrence of critical energies -- where the Lyapunov exponent vanishes -- in random Schr\"odinger operators when the potential have some local order, which we call {\em random palindrome models}. We give necessary and sufficient conditions for the presence of such critical energies: the commutativity of finite word elliptic transfer matrices. Finally, we perform some numerical calculations of the Lyapunov exponents showing their behaviour near the critical energies and the respective time evolution of an initially localized wave packet, obtaining the exponent ruling the algebraic growth of the second momentum. We also consider special random palindrome models with one-letter bounded gap property; the transport effects of such long range order are showed numerically.

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