  The experimental observation of quantum jumps is an example of single open
quantum systems that, when monitored, evolve in terms of stochastic
trajectories conditioned on measurements results. Here we present a proposal
that allows the experimental observation of a much larger class of quantum
trajectories in cavity QED systems. In particular, our scheme allows for the
monitoring of engineered thermal baths that are crucial for recent proposals
for probing entanglement decay and also for entanglement protection. The scheme
relies on the interaction of a three-level atom and a cavity mode that
interchangeably play the roles of system and probe. If the atom is detected the
evolution of the cavity fields follows quantum trajectories and vice-versa.
