Quantum-state control by a single conditional measurement: The periodically switched Jaynes-Cummings model

A mechanism for controlling arbitrary quantum-field states in a cavity is proposed. It is based on a single conditional measurement of the state of a two-level atom, following a periodic sequence of field-atom couplings with alternating near-resonant and off-resonant detunings. The resulting field state is controlled by the arbitrarily large number of parameters that characterize the sequence of detunings. © 1996 The American Physical Society.