Schemes of Implementing a Two-Atom Iswap Gate via Cavity QED

Taoufik Said, A. Chouikh, Mohamed Bennai

Qi Liu, 叶柳

Wen-Peng Liu, Ye Liu Song Xue-ke

Moteb M. Alqahtani, Mark S. Everitt, B. M. Garraway

Abstract Based on a cavity QED framework, we theoretically describe a universal set of logic gates which are implemented by passing a multi-level atom initially in its ground state through a multi-mode cavity. The qubits are encoded on the cavity modes and the atom plays the role of an ancilla which will not be entangled with the final result of a gate operation. We apply the multiphoton resonance theory of Shore to develop effective two- and three-level Hamiltonians, so that the proper values for detunings, coupling coefficients, and interaction times for gate operations can be determined. This enables us to examine a faster iSWAP gate than our previous study and to examine numerically the effects of decoherence on both the iSWAP gate and our previously presented Fredkin gate which used the same multi-mode approach. We also present results that show how conditional measurements of the ancilla atom can improve gate fidelities in these cases.

Liu Qi, Liu Ye

We implement a two-atom (swap) 1/2 gate via cavity QED. During the preparation, a cavity-assisted collision between atoms is required, and this does not need any auxiliary atom. The cavity is only virtually excited, thus our scheme is insensitive to the cavity field states and to the cavity decay. The scheme can be implemented by the present cavity QED techniques.

Jie Song, Yan Xia, Xiudong Sun +1 more

An effective approach to the construction of iSWAP gate has been proposed. Working with three atoms inside three coupled cavities, we analyze the transport and the confinement of a single photon along two different directions. It is shown that two $Q$ switches can be built by tuning the transition energy of each atom. Applying a classical field, we can implement high-speed gate operation between photon and atom. In addition, the influence of decoherence on the gate fidelity is also discussed.