  The Zeno and anti-Zeno effects are features of measurement-driven quantum
evolution where frequent measurement inhibits or accelerates the decay of a
quantum state. Either type of evolution can emerge depending on the
system-environment interaction and measurement method. In this experiment, we
use a superconducting qubit to map out both types of Zeno effect in the
presence of structured noise baths and variable measurement rates. We observe
both the suppression and acceleration of qubit decay as repeated measurements
are used to modulate the qubit spectrum causing the qubit to sample different
portions of the bath. We compare the Zeno effects arising from dispersive
energy measurements and purely-dephasing `quasi'-measurements, showing energy
measurements are not necessary to accelerate or suppress the decay process.
