****TECHNICAL ABSTRACT**** This project will address topologically non-trivial properties of degenerate states in low dimensional hole gases. Non-Abelian phases will be measured in double-ring interferometric devices, where the contribution of Abelian phases can be minimized. Excitations with non-Abelian statistics will be studied in 1D semiconducting wires proximity-coupled to a conventional superconductor. Complementary experiments exploring the energy spectrum of bound states and phase-energy relation of Josephson junctions will be performed. Several fabrication approaches are proposed to reduce effects of localization, the major complication in mesoscopic devices. Finally, an interplay between non-Abelian nature of the wavefunction and non-Abelian statistics of excitation will be investigated. This project will support a PhD student who will be trained in semiconductor physics, fabrication and measurement techniques, including low temperature high magnetic field techniques, vacuum technology, low noise electrical characterization, scanning probe and electron-beam nanolithography. This broad experience will prepare the student for a successful career in technology or academia. An outreach program includes development of nanotechnology demonstrations and accompanying materials for high school students and physics teachers.
Quantum statistics, spin and symmetry of the wavefunction are central to the quantum mechanical understanding of the world. In most systems phases accumulated by a particle along a trajectory are additive and exchange of two particles amounts to a multiplication by a phase factor. However, over the last few decades it has been realized that in very special settings the accumulated phase depends on the topology of the system and particle exchanges do not have to commute, meaning the outcome of permutations depends on the order of the particle exchanges. The main objective of this work is to engineer a new state of matter where exotic particles with non-commuting properties can exist. New techniques to detect particles with these unconventional properties will be also developed. If successful, the research will enable development of a topological quantum bit, a key element of a revolutionary concept of a fault-tolerant quantum computer, which promises to increase computational power for some resource-intensive tasks exponentially, especially for encryption algorithms paramount for national security. The project will train a PhD student working at the edge of nanotechnology, which is the best hands-on training in science and engineering for a successful career in technology or academia. An outreach program includes development of nanotechnology demonstrations and accompanying materials for high school students and physics teachers.
