Spectral Properties of Small Hadamard Matrices

Dorin Ervin Dutkay, Eric Weber, John Haussermann

We prove that if $A$ and $B$ are Hadamard matrices which are both of size $4\times 4$ or $5\times 5$ and in dephased form, then $tr(A)=tr(B)$ implies that $A$ and $B$ have the…