We propose a method to prepare entangled states and implement quantum computation with atoms in optical cavities. The internal states of the atoms are entangled by a measurement of the phase of light transmitted through the cavity. By repeated measurements an entangled state is created with certainty, and this entanglement can be used to implement gates on qubits which are stored in different internal degrees of freedom of the atoms. This method, based on measurement induced dynamics, has a higher fidelity than schemes making use of controlled unitary dynamics.

• Received 1 April 2003

DOI:https://doi.org/10.1103/PhysRevLett.91.097905