Quantum memory effects in atomic ensembles coupled to photonic cavities

Quantum Optics with Atomic Ensembles and Single Atoms in Cavities

Current experiments in our group explore the quantum interface between matter and light, with the goal of achieving coherent control for implementing quantum information protocols and quantum networks. We outline recent progress in this direction, including localization to the ground state of motion for an atom trapped in an optical cavity, observation of strong coupling between single Cesium a...

Efficient atomic quantum memory for photonic qubits in cavity QED

We investigate a scheme of atomic quantum memory to store photonic qubits of polarization in cavity QED. It is observed that the quantum-state swapping between a single-photon pulse and a Λ-type atom can be made via scattering in an optical cavity [T. W. Chen, C. K. Law, P. T. Leung, Phys. Rev. A 69 (2004) 063810]. This swapping operates limitedly in the strong coupling regime for Λ-type atoms ...

Quantum communication and memory with entangled atomic ensembles

Quantum information processing, a rapidly developing area of physics, involves operations with quantum states, in which information can be encoded. The number of degrees of freedom available for the encoding grows dramatically, as compared to classical encoding, due to the existence of quantum superpositions. One of the necessary components for quantum information processing is the quantum stat...

Quantum dots in photonic crystal cavities

Universal quantum gates for hybrid system assisted by atomic ensembles embedded in double-sided optical cavities

We propose deterministic schemes for controlled-NOT (CNOT), Toffoli, and Fredkin gates between flying photon qubits and the collective spin wave (magnon) of an atomic ensemble inside double-sided optical microcavities. All the gates can be accomplished with 100% success probability in principle and no additional qubit is required. Atomic ensemble is employed so that light-matter coupling is rem...