Preparing for a next-generation measurement of the fine-structure constant*

Using Bragg diffraction and Bloch oscillations a simultaneous conjugate Ramsey-Bordé matterwave interferometer is implemented to measure the fine-structure constant. To control systematic effects related to the spatial shape of the laser that is responsible for implementing Bragg diffraction and Bloch oscillations, we use a large-diameter laser beam in which deviations from the ideal Gaussian shape are well-controlled. Remaining systematic effects related to beam imperfections will be understood by comparing a simulation to experiment data where the beam is distorted in a controlled manner.