We propose a scheme to implement a two-qubit conditional quantum phase gate for the intracavity field via a single three-level Λ-type atom driven by two modes in a high-Q cavity. The quantum information is encoded on the Fock states of the bimodal cavity. The gate's averaged fidelity is expected to reach 99.8%.
A single three-level atom driven by a longitudinal mode of a high-Q cavity is used to implement two-qubit quantum phase gates for the intracavity field. The two qubits are associated with the zero- and one-photon Fock states of each of the two opposite circular polarization states of the field. The three-level atom mediates the conditional phase gate provided the two polarization states and the atom interact in a V-type configuration and the two-photon resonance condition is satisfied. Microwave and optical implementations are discussed with gate fidelities being evaluated against several decoherence mechanisms such as atomic velocity fluctuations or the presence of a weak magnetic field. The use of coherent states for both polarization states is investigated to assess the entanglement capability of the proposed quantum gates.
A scheme is proposed to realize a two-qubit quantum phase gate for the intracavity modes. In the scheme, two qubits are encoded in zero- and one-photon Fock states of two intracavity modes, and the three-level $\ensuremath{\Lambda}$-type atom trapped in a high-Q cavity mediates the conditional phase gate within a given interaction time. The influence of cavity decay and atomic spontaneous emission on the gate fidelity is also discussed.
In this work, a single three-level atom driven by a single longitudinal mode of a high-Q cavity is used to implement two-qubit quantum phase gates (QPG) for the intracavity field. The two qubits are associated with the zero- and one-photon Fock states of each of the two opposite circular polarization states of the field. The three-level atom mediates the conditional phase gate provided the two circular polarization states and the atom interact in a V-type configuration and the two-photon resonance condition is satisfied.
We propose a scheme for implementing a two-qubit quantum phase gate for intracavity fields. In the scheme, two qubits are encoded in zero- and one-photon Fock states of two intracavity modes, and a four-level N-type atomic ensemble trapped in a cavity mediates the conditional phase gate within a given interaction time. We also discuss the influence of the atomic spontaneous emission and the decay of the cavity modes on the photon loss and gate fidelity, showing the scheme is within the current experiment technology.