It is shown that distinct atomic beams can be entangled when they interact with quantum superpositions of macroscopically separated micromaser fields. Experimentally feasible tests of complementarity are proposed, detecting Ramsey interference (or not) in one and ‘‘Welcher Weg’’ information (or not) in the other entangled beam. Available information and fringe contrast can be manipulated using classical and quantum fields. The ‘‘quantum eraser’’ is realized in the former case, while it is only a special feature in the latter one. Other applications of entangled atoms are also suggested. © 1996 The American Physical Society.

• Received 2 August 1995

DOI:https://doi.org/10.1103/PhysRevA.53.49