Fast and High-Fidelity Motional-State-Preserving Transport in Optical Tweezers

Reconfigurable neutral-atom processors require rapid, high-fidelity transport of atoms between optical-tweezer sites. In finite-depth Gaussian traps, fast motion can leave residual motional excitation even when the atom reaches its destination. We develop a basis-parameterized gradient-ascent pulse-engineering (GRAPE) framework for one-dimensional transport of a single ${}^{87}$Rb atom. A shortcut-to-adiabaticity reference is refined using 17 trajectory parameters, with ten additional parameters providing bounded trap-depth modulation; depth affects both confinement and the inverse construction of the physical trap center. For a $12.6\mu$m transfer completed in only $30.5\mu$s, corresponding to approximately $2.75$ periods of the reference trap, the selected joint protocol achieves a ground-state infidelity of $2.41\times {10}^{-7}$. Because preparing an exactly pure motional ground state is experimentally challenging, we also optimize population-weighted transport for initial distributions with mean vibrational occupations $\text{nbar}\simeq 0.16$ and $1.87$, reaching same-state probabilities of about $0.99993$ and $0.9934$. Trap-depth fluctuations can further degrade transport fidelity. Robust optimization under a measurement-informed depth-noise model improves the mean error, worst sampled error, and fidelity dispersion for the specified noise realizations. Coordinated control of tweezer position and confinement thus offers a route to rapid transport with low residual excitation for flexible atom rearrangement and dynamic connectivity in neutral-atom processors.