Welte, Stephan

Date:    Wednesday, Oct 27, 2021
Time:   13:00
Place:   ETH Zurich, Campus Hönggerberg, HIT F 11.1 & scheduled Zoom meeting
Host:    Jonathan Home

Quantum networks with neutral atoms in optical cavities

Stephan Welte
Max Planck Institute for Quantum Optics, Germany

Cavity QED systems constitute an ideal interface to connect flying and stationary qubits in a quantum network. The stationary qubits can be realized with trapped neutral atoms, while the flying qubits are encoded either in the polarization degree of a photon or in the phase of a coherent laser pulse. I will present a series of experiments employing the strong nonlinearity provided single atoms in two cavity QED setups to implement useful tools for quantum information processing and quantum communication in a network-ready architecture. These tools comprise a photon-photon quantum gate mediated by an intra-cavity atom and a gate between two atoms in one cavity executed via the reflection of a single photon. Furthermore, the atom-cavity system also allows for the deterministic generation of entangled atom-light Schrödinger-cat states. I will show how the connection of two cavity QED setups can be employed to implement a nonlocal quantum gate between two atoms located in 60m distant cavities. Also, the same system can be used to perform teleportation of quantum information from one atom to the other and to nondestructively detect flying optical photons multiple times.