Trapped ion quantum computing (TIQC), with its large decoherence times and small operation times relative to other physical quantum computing architectures, has garnered significant attention in the public and private sectors. Planar Paul traps, which simultaneously utilize radio frequency and static voltages in a two-dimensional electrode array to spatially confine ions, are the primary candidates for trapping ions for TIQC due to their manufacturability and ability to shuttle ions between multiple trapping zones for quantum logic gates and memory storage. The growing relevance of this technology necessitates educating students about the advanced electrodynamics of ion trapping and ion shuttling. Therefore, I developed a macroscopic planar Paul trap which utilizes 50µm diameter proxy-ions along with high voltage (HV) alternating currents (AC) at 60 Hz and HV direct currents (DC). These are applied to a 5-rail electrode geometry to demonstrate ion shuttling and ion-group splitting along a linear trapping axis. The goal is to educate students on the electrodynamics of ion traps by allowing them to experiment with the tunable trapping parameters, such as AC voltage amplitudes, DC voltage magnitudes, and applied shuttling waveforms and observe the changes in the dynamics of the proxy-ions relative to theoretical predictions. I designed the trap by implementing the recommended relative electrode dimensions into COMSOL Multiphysics and optimizing the geometry by maximizing the pseudopotential confinement while simultaneously minimizing electrode surface area. Afterwards, I utilized an analytic model of a 5-rail planar Paul trap, along with the method of Lagrange multipliers, to optimize the voltage magnitude and waveform of the segmented electrodes for smooth, effective shuttling and ion-group splitting. I then integrated an HV relay circuit and the 5-rail electrode geometry onto printed circuit boards to allow for student-controlled ion shuttling via an Arduino microcontroller.

In quantum computing, computer engineers require a method to control the logical state of a quantum bit (qubit). Unlike its classical counterpart, a qubit’s logical state is not defined by a binary and discrete voltage. The QT3 lab is developing a quantum testbed with a defect in diamond known as the nitrogen-vacancy (NV) center. We present an on-diamond antenna that is optimized to manipulate the electron spin state of an NV center, which defines the qubit. Applying a radiofrequency magnetic field equal to the energy difference between the two spin states of our qubit, also known as resonant excitation, enables control of this state. The strength of this field directly correlates to the frequency at which this manipulation may occur. That frequency is known as the Rabi frequency. This is important as we want this frequency to be faster than the state can undergo decoherence, where state information is lost to the environment of the qubit. We have designed and simulated an antenna using finite element analysis software, which will supply our field and be fabricated on the diamond surface. For its geometry we realized a coplanar waveguide with a shorted end shaped around the NV center, which optimizes the field strength at the NV center, power reflections, and area consumption. Preliminary fabricated samples have been mounted, wirebonded, and characterized using a vector network analyzer, and have shown behavior that aligns with simulated results. We expect to have the antenna fabricated on our single NV center testbed sample and achieve a Rabi frequency on the order of 10’s of MHz. Once this sample is fully integrated into our cryogenic system, it will enable us to expand control to multiple nuclear spin qubits from a single NV center, as a quantum register. The testbed will be accessible to researchers and educators.