Abstract

This presentation reports on the work carried out during a six-month PhD placement at SECQAI , which focused on the application of both classical and quantum density functional theory (DFT) methods to problems in materials science. Two main research directions were pursued.

The first project aimed to identify desirable material properties for single-photon avalanche diodes (SPADs), devices that are widely used in quantum optics and quantum communication. The approach was to relate key performance metrics such as photon detection efficiency, timing jitter, and dark count rate to underlying material parameters. These dependencies were derived using analytical models and linked to quantities accessible via first-principles calculations. This work forms the basis for the development of high-throughput computational workflows for automated materials screening in SPAD applications.

The second project explored the implementation of plane-wave DFT calculations on quantum hardware using the variational quantum eigensolver (VQE) algorithm. An analysis of the numerical complexity of classical DFT was carried out, and a prototype VQE implementation was developed within the ABINIT simulation package. The project identified the main computational challenges involved and outlined the necessary steps for realizing a quantum advantage in this context.

The presentation will provide an overview of both projects, including theoretical background, methods, and results