Semiconductor Quantum Bits

This book highlights state-of-the-art qubit implementations in semiconductors and provides an extensive overview of this newly emerging field. Semiconductor nanostructures have huge potential as future quantum information devices as they provide various ways of qubit implementation (electron spin, electronic excitation) as well as a way to transfer quantum information from stationary qubits to flying qubits (photons). Therefore, this book unites contributions from leading experts in the field, reporting cutting-edge results on spin qubit preparation, read-out and transfer. The latest theoretical as well as experimental studies of decoherence in these quantum information systems are also provided. Novel demonstrations of complex flying qubit states and first applications of semiconductor-based quantum information devices are given, too.

This book highlights state-of-the-art qubit implementations in semiconductors and provides an extensive overview of this newly emerging field. Semiconductor nanostructures have huge potential as future quantum information devices as they provide various ways of qubit implementation (electron spin, electronic excitation) as well as a way to transfer quantum information from stationary qubits to flying qubits (photons). Therefore, this book unites contributions from leading experts in the field, reporting cutting-edge results on spin qubit preparation, read-out and transfer. The latest theoretical as well as experimental studies of decoherence in these quantum information systems are also provided. Novel demonstrations of complex flying qubit states and first applications of semiconductor-based quantum information devices are given, too.

A quantum dot is a particle of matter so small that the addition or removal of an electron changes its properties in some useful way. All atoms are quantum dots, but multi-molecular combinations can have this characteristic. In biochemistry, quantum dots are called redox groups. In nanotechnology, they are called quantum bits or qubits. Quantum dots typically have dimensions measured in nanometers, where one nanometer is 10-9 meter or a millionth of a millimetre. The fields of biology, chemistry, computer science, and electronics are all of interest to researchers in nanotechnology. Other applications of quantum dots include nanomachines, neural networks, and high-density memory or storage media. Research is being carried out on nano-crystals, self-assembled dots, and gated structures. This book presents leading-edge research from around the world.

The present book provides to the main ideas and techniques of the rapid progressing field of quantum information and quantum computation using isotope - mixed materials. It starts with an introduction to the isotope physics and then describes of the isotope - based quantum information and quantum computation. The ability to manipulate and control electron and/or nucleus spin in semiconductor devices provides a new route to expand the capabilities of inorganic semiconductor-based electronics and to design innovative devices with potential application in quantum computing. One of the major challenges towards these objectives is to develop semiconductor-based systems and architectures in which the spatial distribution of spins and their properties can be controlled. For instance, to eliminate electron spin decoherence resulting from hyperfine interaction due to nuclear spin background, isotopically controlled devices are needed (i.e., nuclear spin-depleted). In other emerging concepts, the control of the spatial distribution of isotopes with nuclear spins is a prerequisite to implement the quantum bits (or qbits). Therefore, stable semiconductor isotopes are important elements in the development of solid-state quantum information. There are not only different algorithms of quantum computation discussed but also the different models of quantum computers are presented. With numerous illustrations this small book is of great interest for undergraduate students taking courses in mesoscopic physics or nanoelectronics as well as quantum information, and academic and industrial researches working in this field.

Semiconductor quantum science and technology is exploring the exciting and emerging prospects of integrating quantum functionality on semiconductor platforms to convert current information technology into quantum information technology. The past twenty years have led to incredible advances in this field. This book brings together the leading scientists who present the main achievements and challenges by reviewing and motivating the state-of-the-art at a tutorial level. The key challenges include creating quantum-light sources, quantum information processing via strong light-matter interaction, discovering new quantum materials as well as quasiparticles, and determining new quantum spectroscopic methodologies for superior control of quantum phenomena. As an important step, integration of these solutions on a semiconductor chip is discussed, and outlook for the future of semiconductor quantum science and technology is given. Leading experts present their vision on semiconductor quantum science and technology All aspects needed to realize semiconductor quantum science and technology are explained Quantum semiconductors from overviewed a tutorial introduction to the state-of-the-art

This book discusses the basic physics of semiconductor macroatoms at the nanoscale as well as their potential application as building blocks for the realization of new-generation quantum devices. It provides a review on state-of-the art fabrication and characterization of semiconductor quantum dots aimed at implementing single-electron/exciton devices for quantum information processing and communication. After an introductory chapter on the fundamentals of quantum dots, a number of more specialized review articles presents a comprehensive picture of this rapidly developing field, specifically including strongly multidisciplinary topics such as state-of-the-art nanofabrication and optical characterization, fully microscopic theoretical modeling of nontrivial many-body processes, as well as design and optimization of novel quantum-device architectures. Contents: Fundamentals of Zero-Dimensional NanostructuresGrowth and Characterization of Self-Assembled Semiconductor MacroatomsUltrafast Coherent Spectroscopy of Single Semiconductor Quantum DotsFew-Particle Effects in Semiconductor Macroatoms/MoleculesElectron-Phonon Interaction in Semiconductor Quantum DotsPhonon-Induced Decoherence in Semiconductor Quantum DotsAll-Optical Schemes for Quantum Information Processing with Semiconductor MacroatomsNovel Devices for the Measurement of Electronic States in Semiconductor Quantum Dots Readership: Graduate students and academics in condensed matter physics, semiconductors and related area, and electron state in nanoscale systems. Key Features:Unique combination of introductory/review material on quantum-dot physics and most advanced research results in this rapidly developing fieldStrong and continuous link between nanodevice fabrication/characterization and theoretical modeling/simulationCohesive and selfcontained treatment of diverse issues related to semiconductor-device physics and nanotechnologyMost of the scientific activity presented in the book is the result of a number of cross-collaborations within a large-scale European Project, thus the volume offers a cohesive perspective on the many research areas involvedKeywords:Semiconductor Macroatoms;Quantum Dots;Quantum Devices;Quantum Information;Quantum Computation;Few-Electron Systems;Nanofabrication;Ultrafast Spectroscopy

Primary goal of this book is to provide a cohesive description of the vast field of semiconductor quantum devices, with special emphasis on basic quantum-mechanical phenomena governing the electro-optical response of new-generation nanomaterials. The book will cover within a common language different types of optoelectronic nanodevices, including quantum-cascade laser sources and detectors, few-electron/exciton quantum devices, and semiconductor-based quantum logic gates. The distinguishing feature of the present volume is a unified microscopic treatment of quantum-transport and coherent-optics phenomena on ultrasmall space- and time-scales, as well as of their semiclassical counterparts.

Reducing the size of a coherently grown semiconductor cluster in all three directions of space to a value below the de Broglie wavelength of a charge carrier leads to complete quantization of the energy levels, density of states, etc. Such “quantum dots” are more similar to giant atoms in a dielectric cage than to classical solids or semiconductors showing a dispersion of energy as a function of wavevector. Their electronic and optical properties depend strongly on their size and shape, i.e. on their geometry. By designing the geometry by controlling the growth of QDs, absolutely novel possibilities for material design leading to novel devices are opened. This multiauthor book written by world-wide recognized leaders of their particular fields and edited by the recipient of the Max-Born Award and Medal 2006 Professor Dieter Bimberg reports on the state of the art of the growing of quantum dots, the theory of self-organised growth, the theory of electronic and excitonic states, optical properties and transport in a variety of materials. It covers the subject from the early work beginning of the 1990s up to 2006. The topics addressed in the book are the focus of research in all leading semiconductor and optoelectronic device laboratories of the world.