Altaf H. Nizamani

We investigate optimized vertical ion-shuttling protocols for trapped-ion applications across a range of ion-trap experiments, including three-dimensional gradient-measurement sensors, on-chip ion fluorescence collection and imaging, improved laser accessibility, and quantum information processing. In this work, we focus on minimizing motional energy gain during ion transport. Our findings indicate that anomalous heating becomes the dominant limiting factor only for shuttling durations exceeding \SI{500}{\micro\second}, whereas the final motional excitation is strongly dependent on the selected shuttling protocol. Using a recently measured heating rate of $(3.1 \pm 0.35)$ quanta\,ms$^{-1}$ at an ion--surface separation of $134 \pm 1.5\,\si{\micro\meter}$, we demonstrate that the motional excitation can be restricted to fewer than eight quanta when the ion is vertically displaced to \SI{86}{\micro\meter} from its initial position at \SI{134}{\micro\meter} within \SI{500}{\micro\second}. These results establish the feasibility of near-adiabatic vertical ion shuttling compatible with the operational requirements of high-fidelity quantum sensing and scalable quantum information processing applications.

We present the design and operation of an ytterbium ion trap experiment with a setup offering versatile optical access and 90 electrical inter-connects that can host advanced surface and multi-layer ion trap chips mounted on chip carriers. We operate a macroscopic ion trap compatible with this chip carrier design and characterise its performance, demonstrating secular frequencies >1 MHz, and trap and cool nearly all of the stable isotopes, including 171Yb+ ions, as well as ion crystals. For this particular tap we measure the motional heating rate, <n-dot>, and observe a <n-dot> proportional to 1/omega^2 behaviour for different secular frequencies, omega. We also determine a spectral noise density S_E(1 MHz) = 3.6(9)x10^-11 V^2 m^-2 Hz^-1 at an ion electrode spacing of 310(10) mu m. We describe the experimental setup for trapping and cooling Yb+ ions and provide frequency measurements of the 2S_1/2 - 2P_1/2 and 2D_3/2 - 3D[3/2]_1/2 transitions for the stable 170Yb+, 171Yb+, 172Yb+, 174Yb+ and 176Yb+ isotopes which are more precise than previously published work.

For many quantum information implementations with trapped ions, effective shuttling operations are important. Here we discuss the efficient separation and recombination of ions in surface ion trap geometries. The maximum speed of separation and recombination of trapped ions for adiabatic shuttling operations depends on the secular frequencies the trapped ion experiences in the process. Higher secular frequencies during the transportation processes can be achieved by optimising trap geometries. We show how two different arrangements of segmented static potential electrodes in surface ion traps can be optimised for fast ion separation or recombination processes. We also solve the equations of motion for the ion dynamics during the separation process and illustrate important considerations that need to be taken into account to make the process adiabatic.