Quantum Information Processing With Continuous Variables And Atomic Ensembles

Quantum information describes the new field which bridges quantum physics and information science. The quantum world allows for completely new architectures and protocols. While originally formulated in continuous quantum variables, the field worked almost exclusively with discrete variables, such as single photons and photon pairs. The renaissance of continuous variables came with European research consortia such as ACQUIRE (Advanced Coherent Quantum Information Research) in the late 1990s, and QUICOV (Quantum Information with Continuous Variables) from 2000OCo2003. The encouraging research results of QUICOV and the new conference series CVQIP (Continuous Variable Quantum Information Processing) triggered the idea for this book. This book presents the state of the art of quantum information with continuous quantum variables. The individual chapters discuss results achieved in QUICOV and presented at the first five CVQIP conferences from 2002OCo2006. Many world-leading scientists working on continuous variables outside Europe also contribute to the book.

Quantum information processing offers fundamental improvements over classical information processing, such as computing power, secure communication, and high-precision measurements. However, the best way to create practical devices is not yet known. This textbook describes the techniques that are likely to be used in implementing optical quantum information processors. After developing the fundamental concepts in quantum optics and quantum information theory, the book shows how optical systems can be used to build quantum computers according to the most recent ideas. It discusses implementations based on single photons and linear optics, optically controlled atoms and solid-state systems, atomic ensembles, and optical continuous variables. This book is ideal for graduate students beginning research in optical quantum information processing. It presents the most important techniques of the field using worked examples and over 120 exercises.

Quantum information may sound like science fiction but is, in fact, an active and extremely promising area of research, with a big dream: to build a quantum computer capable of solving problems that a classical computer could not even begin to handle. Research in quantum information science is now at an advanced enough stage for this dream to be credible and well-worth pursuing. It is, at the same time, too early to predict how quantum computers will be built, and what potential technologies will eventually strike gold in their ability to manipulate and process quantum information. One direction that has reaped many successes in quantum information processing relies on continuous variables. This area is bustling with theoretical and experimental achievements, from continuous-variable teleportation, to in-principle demonstrations of universal computation and efficient error correction. Now the time has come to compile some of the major results into one volume. In this book the leading researchers of the field present up-to-date developments of continuous-variable quantum information. This book is organized to suit many reader levels with introductions to every topic and in-depth discussions of theoretical and experimental results.

Presents the lecture notes of the Les Houches Summer School on Quantum entanglement and information processing. This book aims to establish connections between the communities of quantum optics and of quantum electronic devices working in the area of quantum computing. It is useful for graduate students with a basic knowledge of quantum mechanics.

Quantum information processing offers fundamental improvements over classical information processing, such as computing power, secure communication, and high-precision measurements. However, the best way to create practical devices is not yet known. This textbook describes the techniques that are likely to be used in implementing optical quantum information processors. After developing the fundamental concepts in quantum optics and quantum information theory, the book shows how optical systems can be used to build quantum computers according to the most recent ideas. It discusses implementations based on single photons and linear optics, optically controlled atoms and solid-state systems, atomic ensembles, and optical continuous variables. This book is ideal for graduate students beginning research in optical quantum information processing. It presents the most important techniques of the field using worked examples and over 120 exercises.

This Fermi Summer School of Physics on "Experimental Quantum Information and Computing" represents a primer on one of the most intriguing and rapidly expanding new areas of physics. In this part, the interest in quantum information (QI) science is due to the discovery that a computer operating on quantum mechanical principles can solve certain important computational problems exponentially faster than any conceivable classical computer. But this interest is also due to the interdisciplinary nature of the field: the rapid growth is attributable, in part, to the stimulating confluence of researchers and ideas from physics, chemistry, mathematics, information theory, and computer science. Physics plays a paramount role in QI science, as we realize that computing is itself a physical process subject to physical laws. The incredible growth of classical computers and information processors in the 20th century stems from Turing's notion that a computer is independent of the physical device actually being used; be they relays, vacuum tubes, or semiconductor transistors. As we strive to build useful quantum information processors into the 21st century, we thus look for any physical system that obeys the laws of quantum mechanics, from single photons and atoms to quantum superconducting devices. These Fermi lectures take us on a journey through these and other promising current experimental candidates for QI processing, spanning quantum optics and laser physics, atomic and molecular physics, physical chemistry, and condensed-matter physics. While this broad coverage of experimental physics represents a challenge to the student, such an appreciation of these fields will be critical in the future success of quantum technology. Indeed, the most exciting feature of QI science is that the technology ultimately leading to a quantum processor is likely presently unknown.

The rapid development of quantum technologies has driven a revolution in related research areas such as quantum computation and communication, and quantum materials. The first prototypes of functional quantum devices are beginning to appear, frequently created using ensembles of atoms, which allow the observation of sensitive, quantum effects, and have important applications in quantum simulation and matter wave interferometry. This modern text offers a self-contained introduction to the fundamentals of quantum atom optics and atomic many-body matter wave systems. Assuming a familiarity with undergraduate quantum mechanics, this book will be accessible for graduate students and early career researchers moving into this important new field. A detailed description of the underlying theory of quantum atom optics is given, before development of the key, quantum, technological applications, such as atom interferometry, quantum simulation, quantum metrology, and quantum computing.

The Antikythera mechanism was probably the world’s first ‘analog computer’ — a sophisticated device for calculating the motions of stars and planets. This remarkable assembly of more than 30 gears with a differential mechanism, made on Rhodes or Cos in the first century B.C., revised the view of what the ancient Greeks were capable of creating at that time. A comparable level of engineering didn’t become widespread until the industrial revolution nearly two millennia later. This collection of papers provides a good overview of the current state-of-the-art of quantum information science. We do not know how a quantum Antikythera will look like but all we know is that the best way to predict the future is to create it. From the perspective of the future, it may well be that the real computer age has not yet even begun.