Monroe

Trapped atomic ions are among the most promising candidates for a future quantum information processor, with each ion storing a single quantum bit (qubit) of information. All of the fundamental quantum operations have been demonstrated on this system, and the central challenge now is how to scale the system to larger numbers of qubits. The conventional approach to forming entangled states of multiple trapped ion qubits is through the local Coulomb interaction accompanied by appropriate state-dependent optical forces. Recently, trapped ion qubits have been entangled through a photonic coupling, allowing qubit memories to be entangled over remote distances. This coupling may allow the generation of truly large-scale entangled quantum states, and also impact the development of quantum repeater circuits for the communication of quantum information over geographic distances. I will discuss several options and issues for such atomic quantum networks, along with state-of-the-art experimental progress.