  In a seminal series of papers from the 80's, Lubotzky, Phillips and Sarnak
applied the Ramanujan-Petersson Conjecture for $GL_{2}$ (Deligne's theorem), to
a special family of arithmetic lattices, which act simply-transitively on the
Bruhat-Tits trees associated with $SL_{2}(\mathbb{Q}_{p})$. As a result, they
obtained explicit Ramanujan Cayley graphs from
$PSL_{2}\left(\mathbb{F}_{p}\right)$, as well as optimal topological generators
("Golden Gates") for the compact Lie group $PU(2)$. In higher dimension, the
naive generalization of the Ramanujan Conjecture fails, due to the phenomenon
of endoscopic lifts. In this paper we overcome this problem for $PU_{3}$ by
constructing a family of arithmetic lattices which act simply-transitively on
the Bruhat-Tits buildings associated with $SL_{3}(\mathbb{Q}_{p})$ and
$SU_{3}(\mathbb{Q}_{p})$, while at the same time do not admit any
representation which violates the Ramanujan Conjecture. This gives us Ramanujan
complexes from $PSL_{3}(\mathbb{F}_{p})$ and $PSU_{3}(\mathbb{F}_{p})$, as well
as golden gates for $PU(3)$.
