  We discuss the appearance of Zeno (QZE) or anti-Zeno (QAE) effect in an
exponentially decaying system. We consider the quantum dynamics of a
continuously monitored two level system interacting with a squeezed bath. We
find that the behavior of the system depends critically on the way in which the
squeezed bath is prepared. For specific choices of the squeezing phase the
system shows Zeno or anti-Zeno effect in conditions for which it would decay
exponentially if no measurements were done. This result allows for a clear
interpretation in terms of the equivalent spin system interacting with a
fictitious magnetic field.
