With the help of quantum mechanics, digital quantum hardware may be able to tackle some of the problems that are too difficult for ordinary computers. But despite these expectations and the ongoing... Show moreWith the help of quantum mechanics, digital quantum hardware may be able to tackle some of the problems that are too difficult for ordinary computers. But despite these expectations and the ongoing effort of the research community, reliable quantum computers are not yet realized in a lab setting. The optimal strategies for early applications of such special hardware are not settled either. The present thesis addresses these issues of implementing and harnessing quantum computers.Firstly, several strategies are introduced to implement and characterize digital quantum hardware using the technique called braiding. Two realizations are considered: the edge modes of topological superconductors and the parafermionic modes in Fractional Quantum Hall materials.Secondly, this work explores applying quantum computers to prepare simulated ground states (lowest-energy configurations) of complex quantum systems. To this end, several new techniques are presented in the context of variational quantum algorithms, simulated cooling, and quantum control theory. Show less
The research contained in this thesis lies at the interface between quantum phyiscs, nanotechnology and the theory of computation. Its goal is to design electronic circuits to realize computations... Show moreThe research contained in this thesis lies at the interface between quantum phyiscs, nanotechnology and the theory of computation. Its goal is to design electronic circuits to realize computations that follow the laws of quantum mechanics, and which would allow to execute some algorithms faster than their classical counterparts - for instance, algorithms to solve chemical problems. In particular, these circuits use Majorana modes, very special states which appear in superconductors and are theoretically predicted to protect information from the environment, so that the computation can be executed without errors. The role of my research was to design electronic circuits able to use this fascinating property. Hence, this work is a bridge between some very abstract mathematical ideas and the very concrete world of electronic circuits, made out of inductors and capacitors. Show less
