Hao-Qing Zhang

Scaling of quantum gates remains a central challenge in quantum information science. Ultrafast gates based on spin-dependent kicks provide a promising approach for trapped-ion systems. However, these gates require laser pulses with both high temporal tunability and stability, which are difficult to achieve with existing pulsed sources. Here, we propose a programmable pulsed source that allows flexible control of pulse intensity, waveform, and phase profiles. This enables precise manipulation of pulse sequences, thereby improving the fidelity of entangling gates. Furthermore, since the pulse parameters can be conveniently tuned, various coherent population-transfer schemes can be implemented adiabatic SDKs, thereby improving both the fidelity and robustness of fast quantum gate. Simulation results show that our programmable pulse system can achieve gate fidelities above 99.99% with strong robustness against variations in pulse intensity and single-photon detuning using stimulated Raman adiabatic rapid passage (STIRARP) protocols.

The quantum walk (QW), as the quantum analog of classical random walk, provides a feasible platform to study the topological phenomenon and non-equilibrium dynamics. Here, we propose a novel scheme to realize the quantum walk with a single trapped ion where the Fock states provides the walk space and zero phonon state $\left|n=0\right\rangle $ serves as its natural boundary. Thus, our scheme offers the unique opportunity to investigate the dynamics of the bound states of the corresponding topological systems. Particularly, the quench dynamics of the bound states can be extensively studied by tuning the bulk parameters and the local boundary operator, which are experimentally accessible. Our proposal not only offers a new approach to exploring the character of the bound states of the topological systems, but also offers a way to determine different phases through the dynamical processes.