Detecting Neutral Atoms on an Atom Chip
  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. 
M. Wilzbach, A. Haase, M. Schwarz, D. Heine, K. Wicker, X. Liu, K.-H.   Brenner, S. Groth, Th. Fernholz, B. Hessmo, J. Schmi...