Lanczos Meets Orthogonal Polynomials (Mar. 11, 2026)

  • Published: 2026-03-10

Time: 10:00-12:00, March 11, 2026

Location: Seminar Room of KITS, UCAS

 

Speaker: Lechen QU (IFT, UAM/CSIC)

 

Abstract:

We establish a direct correspondence between the Lanczos approach and the orthogonal polynomials approach in random matrix theory. In the large-$N$ and continuum limits, the average Lanczos coefficients and the recursion coefficients become equivalent, with the precise mapping $b(1-x)=\sqrt{R(x)}$ and $a(1-x)=S(x)$. As a result, the two formalisms yield identical expressions for the leading density of states. We further analyze the Krylov dynamics associated with the recursion coefficients and show that the orthogonal polynomials admit a natural interpretation as Krylov polynomials. This picture is realized explicitly in the Gaussian Unitary Ensemble, where all quantities can be computed analytically.a