Development Of A Robust Platform For Spin Qubits In Sige Heterostructures

Since being proposed almost 40 years ago, scientists across many disciplines have made great progress in the fields of quantum computation and quantum information. Instead of a classical bit (0 or 1), a quantum computer uses a two-level quantum system as a quantum bit or qubit. By controllably manipulating the quantum-mechanical properties of these qubits, a quantum computer could, for example, be used to simulate other, less well understood quantum systems, or to run certain classes of quantum algorithms that cannot be run on classical hardware. In order to build a quantum computer, certain basic requirements must be met. As with a classical computer, logic gates are necessary to controllably manipulate qubits to perform calculations. One such requirement for a universal quantum computer is a two-qubit logic gate. This is an inherently quantum mechanical gate, which has no classical analog. For example, the controlled-not two-qubit gate will perform a not operation on the target qubit if and only if the control qubit is in the one state, else it does nothing to the target qubit. In either case, the control qubit is left unchanged and unmeasured. Being able to perform this gate with high fidelity is critical to creating a quantum computer. In this dissertation, I present progress towards fabricating, characterizing, and manipulating two-qubit devices in Si/SiGe heterostructures. First, I motivate the use of quantum dot qubits hosted in Si/SiGe as a suitable platform for quantum computing. Then, I present characterization of Si/SiGe substrates and discuss fabrication of a quantum dot device. Next, I outline the electronics set up for measuring a quantum dot device in a dilution refrigerator. I then present results of two, published experiments which explore multi-qubit systems: one which demonstrates controllable tunnel coupling between a quantum dot an a nearby localized impurity, and the other which demonstrates state-conditional Landau-Zener-Stückelberg oscillations between capacitively coupled double quantum dots in a quadruple quantum dot device. Next I discuss fabrication and characterization of micromagnets for spin qubit applications. I finally conclude by discussing future research avenues towards realizing a robust, multi-qubit device in silicon.

This book covers recent developments in the understanding, quantification, and exploitation of entanglement in spin chain models from both condensed matter and quantum information perspectives. Spin chain models are at the foundation of condensed matter physics and quantum information technologies and elucidate many fundamental phenomena such as information scrambling, quantum phase transitions, and many-body localization. Moreover, many quantum materials and emerging quantum devices are well described by spin chains. Comprising accessible, self-contained chapters written by leading researchers, this book is essential reading for graduate students and researchers in quantum materials and quantum information. The coverage is comprehensive, from the fundamental entanglement aspects of quantum criticality, non-equilibrium dynamics, classical and quantum simulation of spin chains through to their experimental realizations, and beyond into machine learning applications.

Recent advancements in quantum-enabled systems present a variety of new opportunities and challenges. These technologies are important developments for a variety of computing, communications, and sensing applications. However, many materials and components relevant to quantum-enabled systems exist outside of the United States, and it is important to promote the development of assured domestic sources of materials, manufacturing capabilities, and expertise. The National Academies of Sciences, Engineering, and Medicine convened a 2-day workshop to explore implications and concerns related to the application of quantum-enabled systems in the United States. This workshop focused on quantum-enabled computing systems, quantum communications and networks, and quantum sensing opportunities. Participants explored the path to quantum computing, communications, and networks, opportunities for collaboration, as well as key gaps, supply chain concerns, and security issues. This publication summarizes the presentations and discussions from the workshop.

Single-Atom Nanoelectronics covers the fabrication of single-atom devices and related technology, as well as the relevant electronic equipment and the intriguing new phenomena related to single-atom and single-electron effects in quantum devices. It also covers the alternative approaches related to both silicon- and carbon-based technologies, also

Ongoing developments in nanofabrication technology and the availability of novel materials have led to the emergence and evolution of new topics for mesoscopic research, including scanning-tunnelling microscopic studies of few-atom metallic clusters, discrete energy level spectroscopy, the prediction of Kondo-type physics in the transport properties of quantum dots, time dependent effects, and the properties of interacting systems, e.g. of Luttinger liquids. The overall understanding of each of these areas is still incomplete; nevertheless, with the foundations laid by studies in the more traditional systems there is no doubt that these new areas will advance mesoscopic electron transport to a new phenomenological level, both experimentally and theoretically. Mesoscopic Electron Transport highlights selected areas in the field, provides a comprehensive review of such systems, and also serves as an introduction to the new and developing areas of mesoscopic electron transport.

Softcover version of 2013 Ph.D. thesis of Matthew David Reed presented to the Physics department of Yale University. Concerns the realization of quantum error correction in the circuit quantum electrodynamics architecture, a precursor to quantum computing.

When I was contacted by Kluwer Academic Publishers in the Fall of 200 I, inviting me to edit a volume of papers on the issue of electron transport in quantum dots, I was excited by what I saw as an ideal opportunity to provide an overview of a field of research that has made significant contributions in recent years, both to our understanding of fundamental physics, and to the development of novel nanoelectronic technologies. The need for such a volume seemed to be made more pressing by the fact that few comprehensive reviews of this topic have appeared in the literature, in spite of the vast activity in this area over the course of the last decade or so. With this motivation, I set out to try to compile a volume that would fairly reflect the wide range of opinions that has emerged in the study of electron transport in quantum dots. Indeed, there has been no effort on my part to ensure any consistency between the different chapters, since I would prefer that this volume instead serve as a useful forum for the debate of critical issues in this still developing field. In this matter, I have been assisted greatly by the excellent series of articles provided by the different authors, who are widely recognized as some of the leaders in this vital area of research.