Robust SWAP gate on two distant atoms through virtual excitations and transitionless quantum driving

Abstract

We propose a scheme for implementing robust SWAP gate on two distant atoms that are confined in two spatially separated single-mode optical cavities connected by an optical fiber. The SWAP gate cannot be attained by using adiabatic passage for such a physical model, but we achieve it by following transitionless quantum driving, a method of shortcuts to adiabatic passage. In addition, during the execution of the SWAP gate, none of two atoms, two cavities and the fiber is excited, and thus the virtual excitations of the fiber-cavity-atom system make the scheme very robust against the atomic spontaneous radiation and the decay of the cavities and the fiber. Numerical simulations show that the SWAP gate can be attained with high fidelity, and the present scheme is insensitive to the control errors of various parameters. The scheme may have potential applications in distributed quantum computing and quantum information process in a quantum network.

A shortcut tour of quantum control methods for modern quantum technologies

“…We have used the described STA method in order to maximize entanglement between coupled spins [51] and in a bosonic Josephson junction [57], while we have evaluated its performance for the three-level STIRAP system under the presence of Ornstein-Uhlenbeck noise processes in the energy levels [58]. Other recent works exploit the advantages of this method or its generalizations for quantum state transfer [59][60][61], quantum computation [62][63][64], and sensing [65]. Note that the presented STA method is a specific example of the more general inverse engineering method [12,17,66,67], where the quantum trajectory is prescribed first, eq.…”