We propose a scheme for an optical quantum gate, i.e., a mirror in a quantum superposition state of total transmission and reflection. The model consists of a high- $Q$ optical cavity strongly coupled to a single atom or ion in a quantum superposition state of two long lived internal states. By including spontaneous emission, dissipation, measurement back-action, and the time dependence of the atom-field coupling, we numerically simulate a system very close to experimental reality. The switching and quantum coherence properties are confirmed separately in two steps by using the gate directly and as an entrance beam splitter to an interferometer.We propose a scheme for an optical quantum gate, i.e., a mirror in a quantum superposition state of total transmission and reflection. The model consists of a high-$Q$ optical cavity strongly coupled to a single atom or ion in a quantum superposition state of two long lived internal states. By including spontaneous emission, dissipation, measurement back-action, and the time dependence of the atom-field coupling, we numerically simulate a system very close to experimental reality. The switching and quantum coherence properties are confirmed separately in two steps by using the gate directly and as an entrance beam splitter to an interferometer.

Physical Review AOct 1, 199724 citations

Single-atom interference method for generating quantum states

P. Domokos, József Janszky, Петер Адам

European Quantum Electronics Conference (EQEC)Aug 24, 20050 citations

Scheme for implementation of controlled-not gate and quantum teleportation in a resonant cavity

Shi Shi-wei, You-Min Yi

A scheme is proposed to implement quantum controlled-not(CNOT) gates with a resonant cavity and this quantum gate is used to carry out teleportation of an arbitrary single-atom superposition state.By using three level atoms,it can be realized through single-qubit operation and resonant interaction between two atoms and a resonant cavity.The interaction time between two atoms and the single-mode cavity is very short,which is important in view of decoherence.This character is one of the advantages of this scheme comparing to the scheme based on detuned cavity.A scheme is proposed to implement quantum controlled-not(CNOT) gates with a resonant cavity and this quantum gate is used to carry out teleportation of an arbitrary single-atom superposition state.By using three level atoms,it can be realized through single-qubit operation and resonant interaction between two atoms and a resonant cavity.The interaction time between two atoms and the single-mode cavity is very short,which is important in view of decoherence.This character is one of the advantages of this scheme comparing to the scheme based on detuned cavity.

Chinese Journal of Quantum ElectronicsJan 1, 20090 citations

Quantum Interaction of Single Atoms

HERBERT WALTHER

Jan 1, 20040 citations

Observing the superposition of a single particle with the vacuum

L M Rico-Gutierrez, Veiko Palge, Jacob Dunningham

A defining feature of quantum mechanics is that it allows systems to exist in a superposition of different eigenstates of certain observables such as position or spin. However, superpositions of other quantities such as mass or charge are not seen in nature. It is thought that this disparity is partly due to the fact that it is much easier to carry out interference experiments for certain observables than others. Here we present an interferometry scheme that should allow us to observe interference between the vacuum and a single photon or atom. We begin by presenting a scheme for a Hadamard gate that operates in the Fock state basis and then show how, by creating an interferometer from two such gates, interference between a single particle and the vacuum could indeed be observed. This would provide evidence of a superposition of different particle numbers.A defining feature of quantum mechanics is that it allows systems to exist in a superposition of different eigenstates of certain observables such as position or spin. However, superpositions of other quantities such as mass or charge are not seen in nature. It is thought that this disparity is partly due to the fact that it is much easier to carry out interference experiments for certain observables than others. Here we present an interferometry scheme that should allow us to observe interference between the vacuum and a single photon or atom. We begin by presenting a scheme for a Hadamard gate that operates in the Fock state basis and then show how, by creating an interferometer from two such gates, interference between a single particle and the vacuum could indeed be observed. This would provide evidence of a superposition of different particle numbers.

Mathematical Structures in Computer ScienceNov 8, 20104 citations

We propose a scheme for an optical quantum gate, i.e., a mirror in a quantum superposition state of total transmission and reflection. The model consists of a high-

Q

optical cavity strongly coupled to a single atom or ion in a quantum superposition state of two long lived internal states. By including spontaneous emission, dissipation, measurement back-action, and the time dependence of the atom-field coupling, we numerically simulate a system very close to experimental reality. The switching and quantum coherence properties are confirmed separately in two steps by using the gate directly and as an entrance beam splitter to an interferometer.