Transient nonlinear optical spectroscopy, performed on excitons confined to single GaAs quantum dots, shows oscillations that are analogous to Rabi oscillations in two-level atomic systems. This demonstration corresponds to a one-qubit rotation in a single quantum dot which is important for proposals using quantum dot excitons for quantum computing. The dipole moment inferred from the data is c...

We consider the effective dynamics obtained by double-passing a fardetuned laser probe through a large atomic spin system. The net result of the atomfield interaction is a type of coherent positive feedback that amplifies the values of selected spin observables. An effective equation of motion for the atomic system is presented, and an approximate 2-parameter model of the dynamics is developed ...

We report on the coherent quantum state transfer from a two-level atomic system to a single photon. Entanglement between a single photon (signal) and a two-component ensemble of cold rubidium atoms is used to project the quantum memory element (the atomic ensemble) onto any desired state by measuring the signal in a suitable basis. The atomic qubit is read out by stimulating directional emissio...

We report the experimental demonstration of quantum memory for collective atomic states in a far-detuned optical dipole trap. Generation of the collective atomic state is heralded by the detection of a Raman scattered photon and accompanied by storage in the ensemble of atoms. The optical dipole trap provides confinement for the atoms during the quantum storage while retaining the atomic cohere...

A model of particle interacting with quantum field is considered. The model includes as particular cases the polaron model and non-relativistic quantum elec-trodynamics. We show that the field operators obey q-commutation relations with q depending on time. After the stochastic (or van Hove) limit, due to the nonlin-earity, the atomic and field degrees of freedom become entangled in the sense t...

A model of particle interacting with quantum field is considered. The model includes as particular cases the polaron model and non-relativistic quantum electrodynamics. We show that the field operators obey q-commutation relations with q depending on time. After the stochastic (or van Hove) limit, due to the nonlinearity, the atomic and field degrees of freedom become entangled in the sense tha...

Quantum networks based on atomic qubits and scattered photons provide a promising way to build a largescale quantum information processor. We review quantum protocols for generating entanglement and operating gates between two distant atomic qubits, which can be used for constructing scalable atom–photon quantum networks. We emphasize the crucial role of collecting light from atomic qubits for ...

A scheme for the optimal Gaussian cloning of coherent light states at the interface between light and atoms is proposed. The distinct feature of this proposal is that the clones are stored in an atomic quantum memory, which is important for applications in quantum communication. The atomic quantum cloning machine requires only a single passage of the light pulse through the atomic ensembles fol...