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Rotation numbers for Jacobi matrices with matrix entries

Hermann Schulz-Baldes
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Abstract

A selfadjoined block tridiagonal matrix with positive definite blocks on the off-diagonals is by definition a Jacobi matrix with matrix entries. Transfer matrix techniques are extended in order to develop a rotation number calculation for its eigenvalues. This is a matricial generalization of the oscillation theorem for the discrete analogues of Sturm-Liouville operators. The three universality classes of time reversal invariance are dealt with by implementing the corresponding symmetries. For Jacobi matrices with random matrix entries, this leads to a formula for the integrated density of states which can be calculated perturbatively in the coupling constant of the randomness with an optimal control on the error terms.

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Hermann Schulz-Baldes. 2008-02-20. Rotation numbers for Jacobi matrices with matrix entries. https://arxiv.org/abs/math-ph/0702050

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