  Instanton is known to exist in Euclidean spacetime only. Their role in real
time dynamics is usually understood as tunneling effect by Wick rotation. We
illustrate other effects of instanton in holography by investigating 5d
effective gravity theory of the black D3-brane-D-instanton system. The
supergravity description of the D3-brane-D-instanton system is dual to the
super Yang-Mills theory with topological excitations of the vacuum. We obtain
Euclidean correlators in the presence of instantons by analyzing of the
fluctuations of the bulk fields in the 5d effective theory. Furthermore,
analytic continuation of Euclidean correlators leads to retarded correlators,
which characterize real time dynamics. We find interestingly real time
fluctuations of topological charge can destroy instantons and the lifetime of
instanton is set by temperature. This implies instanton contribution to "real
time dynamics" is suppressed at high temperature, which is analogous to classic
field theory results that instanton contribution to "thermodynamics" is
suppressed at high temperature.
