  We exhibit an operator norm bounded, infinite sequence $\{A_n\}$ of $3n
\times 3n$ complex matrices for which the commutator map $X\mapsto XA_n - A_nX$
is uniformly bounded below as an operator over the space of trace-zero
self-adjoint matrices equipped with Hilbert--Schmidt norm. The construction is
based on families of quantum expanders. We give several potential applications
of these matrices to the study of quantum expanders. We formulate several
natural conjectures and problems related to such matrices and provide numerical
evidence.
