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Probability and Combinatorics

Tuesday, March 19, 2019 - 3:00pm

Fan Yang

UCLA

Location

University of Pennsylvania

DRL 4C8

Abstract: We consider Hermitian random band matrices $H$ in dimension $d$, where the entries $h_{xy}$, indexed by $x,y \in [1,N]^d$, vanishes if $|x-y|$ exceeds the band width $W$. It is conjectured that a sharp transition of the eigenvalue and eigenvector statistics occurs at a critical band width $W_c$, with $W_c=\sqrt{N}$ in $d=1$, $W_c=\sqrt{\log N}$ in $d=2$, and $W_c=O(1)$ in $d\ge 3$. Recently, Bourgade, Yau and Yin proved the eigenvector delocalization for 1D random band matrices with generally distributed entries and band width $W\gg N^{3/4}$. In this talk, we will show that for $d\ge 2$, the delocalization of eigenvectors in certain averaged sense holds under the condition $W\gg N^{2/(2+d)}$. Based on Joint work with Bourgade, Yau and Yin.