Performance benchmarking of silicon quantum processors

Benchmarking the performance of a quantum computer is of key importance in identifying and reducing the error sources, and therefore in achieving fault-tolerant quantum computation. In the last decade, qubits made of electron spins in silicon emerged as promising candidates for practical quantum computers. To understand their physical properties...

Quantum simulation with electron spins in quantum dots

More is more applies in particular to systems with interacting parts. These interactions enable the emergence of collective behaviour. Examples can be found among the behaviour of animals, such as the V-shaped formation of migrating geese and the flight of a flock of starlings. More examples are found among the electromagnetic properties of...

Hot qubits in silicon for quantum computation

The understanding of quantum mechanics enabled the development of technology such as transistors and has been the foundation of today’s information age. Actively using quantum mechanics to build quantum technology may cause a second revolution in handling information. However, to execute meaningful algorithms, largescale quantum computers have...

Circuit Quantum Electrodynamics with Single Electron Spins in Silicon

This dissertation describes a set of experiments with the goal of creating a super-conductor-semiconductor hybrid circuit quantum electrodynamics architecture with single electron spins. Single spins in silicon quantum dots have emerged as attractive qubits for quantum computation. However, how to scale up spin qubit systems remains an open...

Quantum Computation: Shor's algorithm

In recent years, the field of quantum computation has evolved to a promising research area, with the capacity to become as important as classical programming is today. This text serves as an introduction into the field of quantum computation. The main results are a proof that any quantum circuit can be implemented using a finite set of quantum...

Electrical Control, Read-out and Initialization of Single Electron Spins

An electron, in addition to its electric charge, possesses a small magnetic moment, called spin. The spin of an electron can point parallel (spin-up) or antiparallel (spin-down) to the magnetic field. These two states are analogous to zero and one of the logical bit in current digital electronic devices. However, according to the laws of quantum...

Spin and charge in semiconductor nanowires

The research in this thesis is motivated by an interest in quantum physics and by the prospect of new applications based on the spin of electrons or holes. This work focuses on confining single spins in quantum dots, which can serve as building blocks of a future quantum computer. Such a computer exploits the unique features of quantum mechanics...

Coherence and control of a single electron spin in a quantum dot

An electron does not only have an electric charge, but also a small magnetic moment, called spin. In a magnetic field, the spin can point in the same direction as the field (spin-up) or in the opposite direction (spin-down). However, the laws of quantum mechanics also allow the spin to exist in both states at the same time (so-called...

Quantum Superpositions of Persistent Josephson Currents

This thesis presents experimental research on Josephson junction devices that behave quantum mechanically. The devices are formed by micrometer-sized superconducting islands, that are interconnected by a Josephson tunnel junction: a thin insulating layer between two superconductors. With current microfabrication technology it is possible to make...