  We use holography to examine the response of interacting quantum fields to
the appearance of closed timelike curves in a dynamically evolving background
that initially does not contain them. For this purpose, we study a family of
two-dimensional spacetimes that model very broad classes of wormhole time
machines. The behavior of strongly coupled conformal theories in these
spacetimes is then holographically described by three-dimensional AdS bulk
geometries that we explicitly construct. The dual bulk spacetime is free from
any divergences, but splits into two disconnected components, without and with
CTCs, which are joined only through the boundary; then, passages across the
chronology horizon are impossible for any field excitations. In dual terms, the
strong self-interaction of the CFT decouples the pathological part from the
rest of the spacetime. We also find that entangling the CFTs in two separate
time machines connects them through a traversable bulk wormhole. Nevertheless,
any entanglement-assisted chronology violations will be prevented by quantum
bulk corrections, i.e., subleading 1/N effects, again without needing any
gravitational backreaction of the CFT. We are led to speculate that chronology
may be protected without involving Planck scale physics.
