Eigenproblem for Jacobi matrices: hypergeometric series solution

Title	Eigenproblem for Jacobi matrices: hypergeometric series solution
Publication Type	Journal Article
Year of Publication	2007
Authors	Kuznetsov V, Sklyanin E
Journal	Phil. Trans. R. Soc. A
Volume	366
Pagination	1089-1114
Abstract	We study the perturbative power-series expansions of the eigenvalues and eigenvectors of a general tridiagonal (Jacobi) matrix of dimension d. The(small) expansion parameters are being the entries of the two diagonals of length d-1 sandwiching the principal diagonal, which gives the unperturbed spectrum. The solution is found explicitly in terms of multivariable (Horn-type) hypergeometric series of 3d-5 variables in the generic case, or 2d-3 variables for the eigenvalue growing from a corner matrix element. To derive the result, we first rewrite the spectral problem for a Jacobi matrix as an equivalent system of cubic equations, which are then resolved by the application of the multivariable Lagrange inversion formula. The corresponding Jacobi determinant is calculated explicitly. Explicit formulae are also found for any monomial composed of eigenvector's components.
URL	http://www.journals.royalsoc.ac.uk/content/a3w082v0718x35ph/
DOI	10.1098/rsta.2007.2062
E-print number	arXiv:math.CO/0509298
MathRev	MR2377686

Department of Mathematics