PhD defense: Andrea Maiani

Modeling of Hybrid Nanoelectronic Devices for Quantum Information Processing

Hybrid nanoelectronic devices offer a promising platform for developing quantum technologies by combining the macroscopic phase coherence of superconductors with the charge density control of semiconductor devices. This thesis focuses on modeling hybrid nanoelectronic devices and their applications in investigating topological phases of matter and quantum information processing.

The first part of the thesis introduces a novel orbital-free method for electrostatic modeling. This method significantly improves the precision of the density profile near interfaces while minimizing computational costs. Next, we use a symmetry-based approach to nonlocal conductance spectroscopy to investigate transport measurements in multiterminal devices. This approach can identify the direction of spin-orbit coupling and detect non-ideal effects.

The thesis then explores ferromagnetic hybrid heterostructures, which enable local control of effective magnetic fields by incorporating magnetic insulator insets. We examine the interplay of superconducting and ferromagnetic proximity effects and present a planar design for demonstrating topological superconductivity. We also show how this platform can be used to implement configurable 0-\pi Josephson junctions and how it can potentially realize nonsinusoidal current-phase relations.

Finally, the thesis investigates the application of junctions dominated by higher harmonics in superconducting qubits. We propose and study a coupling scheme for entangling to entangle parity-protected qubits with flux-tunable transmons in a heterogeneous quantum architecture.