  Detecting single atoms (qubits) is a key requirement for implementing quantum
information processing on an atom chip. The detector should ideally be
integrated on the chip. Here we present and compare different methods capable
of detecting neutral atoms on an atom chip. After a short introduction to
fluorescence and absorption detection we discuss cavity enhanced detection of
single atoms. In particular we concentrate on optical fiber based detectors
such as fiber cavities and tapered fiber dipole traps. We discuss the various
constraints in building such detectors in detail along with the current
implementations on atom chips. Results from experimental tests of fiber
integration are also described. In addition we present a pilot experiment for
atom detection using a concentric cavity to verify the required scaling.

Atomic Physics