Transitionless-based shortcuts for the fast and robust generation of W states

• In this paper, we have proposed a scheme to fast generate W states via transitionless-based shortcuts. In order to highlight the advantages of the present scheme, we have described two similar schemes based on STIRAP and QZD.
• The comparison among these three schemes demonstrates that the shortcut scheme is faster than the adiabatic one, and more robust against operational imperfection than the Zeno one. Numerical investigation also demonstrates the present scheme is robust against the decoherence caused by both atomic spontaneous emission and photon leakage. When it comes to the generation of N-atom W   states, the only change is setting Ω˜1=−iΩ˜xN−1 and Ω˜2=Ω˜3=⋯=Ω˜N=Ω˜x. Known from ref. [63], the Hamiltonian for a system with three four-level atoms trapped in a cavity also can be approximated into an effective Hamiltonian in form of Eq. (9). For a similar model described in Ref. [64], if the atomic transitions are non-resonant, one can also obtain an effective Hamiltonian in form of Eq. (15). That means, with the same method in Section 3 of the paper, a multi-qubit singlet state also can be fast generated. In addition, the shortcut method might also show its glamour in other fields, for example, fast transfer of entanglement [32] and [65] That demonstrates the present method has a wide rang of application in quantum information processing. This might lead to a useful step toward realizing fast and noise-resistant quantum information processing for multi-qubit systems in current technology.

We propose a scheme to generate W states based on transitionless-based shortcuts technique in cavity quantum electrodynamics (QED) system. In light of quantum Zeno dynamics, we first effectively design a system whose effective Hamiltonian is equivalent to the counter-diabatic driving Hamiltonian constructed by transitionless quantum driving, then, realize the W states' generation within this framework. For the sake of clearness, we describe two stale schemes for W states' generation via traditional methods: the adiabatic dark-state evolution and the quantum Zeno dynamics. The comparison among these three schemes shows the shortcut scheme is closely related to the other two but better than them. That is, numerical investigation demonstrates that the shortcut scheme is faster than the adiabatic one, and more robust against operational imperfection than the Zeno one. What is more, the present scheme is also robust against decoherence caused by spontaneous emission and photon loss.