Exploring the Quantum/Classical Frontier - Recent Advances in Macroscopic Quantum Phenomena

The counter-intuitive aspects of quantum physics have been long illustrated by thought experiments, from Einstein's photon box to Schrödinger's cat. These experiments have now become real, with single particles - electrons, atoms, or photons - directly unveiling the strange features of the quantum. State superpositions, entanglement and complementarity define a novel quantum logic which can be harnessed for information processing, raising great hopes for applications. This book describes a class of such thought experiments made real. Juggling with atoms and photons confined in cavities, ions or cold atoms in traps, is here an incentive to shed a new light on the basic concepts of quantum physics. Measurement processes and decoherence at the quantum-classical boundary are highlighted. This volume, which combines theory and experiments, will be of interest to students in quantum physics, teachers seeking illustrations for their lectures and new problem sets, researchers in quantum optics and quantum information.

This volume is an outgrowth of the Second International Workshop on Macroscopic Quantum Coherence and Computing held in Napoli, Italy, in June 2000. This workshop gathered a number of experts from the major Universities and Research Institutions of several countries. The choice of the location, which recognizes the role and the traditions of Naples in this field, guaranteed the participants a stimulating atmosphere. The aim of the workshop has been to report on the recent theoretical and experimental results on the macroscopic quantum coherence of macroscopic systems. Particular attention was devoted to Josephson devices. The correlation with other atomic and molecular systems, exhibiting a macroscopic quantum behaviour, was also discussed. The seminars provided both historical overview and recent theoretical ground on the topic, as well as information on new experimental results relative to the quantum computing area. The first workshop on this topic, held in Napoli in 1998, has been ennobled by important reports on observations of Macroscopic Quantum Coherence in mesoscopic systems. The current workshop proposed, among many stimulating results, the first observations of Macroscopic Quantum Coherence between macroscopically distinct fluxoid states in rf SQUIDs, 20 years after the Leggett's proposal to experimentally test the quantum behavior of macroscopic systems. Reports on observations of quantum behaviour in molecular and magnetic systems, small Josephson devices, quantum dots have also been particularly stimulating in view of the realization of several possible q-bits.

Quantum information theory has revolutionised our view on the true nature of information and has led to such intriguing topics as teleportation and quantum computation. The field - by its very nature strongly interdisciplinary, with deep roots in the foundations both of quantum mechanics and of information theory and computer science - has become a major subject for scientists working in fields as diverse as quantum optics, superconductivity or information theory, all the way to computer engineers.

Quantum information theory has revolutionised our view on the true nature of information and has led to such intriguing topics as teleportation and quantum computation. The field — by its very nature strongly interdisciplinary, with deep roots in the foundations both of quantum mechanics and of information theory and computer science — has become a major subject for scientists working in fields as diverse as quantum optics, superconductivity or information theory, all the way to computer engineers.The aim of this book is to provide guidance and introduce the broad literature in all the various aspects of quantum information theory. The topics covered range from the fundamental aspects of the theory, like quantum algorithms and quantum complexity, to the technological aspects of the design of quantum-information-processing devices. Each section of the book consists of a selection of key papers (with particular attention to their tutorial value), chosen and introduced by leading scientists in the specific area. An entirely new introduction to quantum complexity has been specially written for the book.

This book is written to conclude the NATO Advanced Research Workshop "Quantum Noise in Mesoscopic Physics" held in Delft, the Netherlands, on June 2-4, 2002. The workshop was co-directed by M. Reznikov of Israel Institute of Technology, and me. The members of the organizing committee were Yaroslav Blanter (Delft), Chirstopher Glattli (Saclay and ENS Paris) and R. Schoelkopf (Yale). The workshop was very successful, and we hope that the reader will be satisfied with the scientific level of the present book. Before addressing scientific issues I find it suitable to address several non-scientific ones. The workshop was attended by researchers from many countries. Most of them perform their activities in academic institutions, where one usually finds the necessary isolation from the problems and sores of the modem world. However, there was a large group of participants for which such isolation was far from perfect. War, hatred, and violence rage just several miles away of their campuses and laboratories, poisoning everyday life in the land of Israel.

During the last ten years Quantum Information Processing and Communication (QIPC) has established itself as one of the new hot topic fields in physics, with the potential to revolutionize many areas of science and technology. QIPC replaces the laws of classical physics applied to computation and communication with the more fundamental laws of quantum mechanics. This becomes increasingly important due to technological progress going down to smaller and smaller scales where quantum effects start to be dominant. In addition to its fundamental nature, QIPC promises to advance computing power beyond the capabilities of any classical computer, to guarantee secure communication and establish direct links to emerging quantum technologies, such as, for example, quantum based sensors and clocks. One of the outstanding feature of QIPC is its interdisciplinary character: it brings together researchers from physics, mathematics and computer science. In particular, within physics we have seen the emergence of a new QIPC community, which ranges from theoretical to experimental physics, and crosses boundaries of traditionally separated disciplines such as atomic physics, quantum optics, statistical mechanics and solid state physics, all working on different and complementary aspects of QIPC. This publication covers the following topics: Introduction to quantum computing; Quantum logic, information and entanglement; Quantum algorithms; Error-correcting codes for quantum computations; Quantum measurements and control; Quantum communication; Quantum optics and cold atoms for quantum information; Quantum computing with solid state devices; Theory and experiments for superconducting qubits; Interactions in many-body systems: quantum chaos, disorder and random matrices; Decoherence effects for quantum computing; and Flature prospects of quantum information processing.

The realizations of physical systems whose quantum states can be directly manipulated have been pursued for experiments on fundamental problems in quantum mechanics and implementations of quantum information devices. Micro-fabricated superconducting systems and electronic spins are among the most promising candidates. This book contains the newest and most advanced research reports on such materials, called OC Mesoscopic SuperconductivityOCO and OC SpintronicsOCO. The former includes superconductor-semiconductor hybrid systems, very small Josephson junctions, and micron-size SQUIDs. The latter includes the control of spin transports in semiconductor heterostructures, nano-scale quantum dots, and spin injections. Superconductor-ferromagnetic metal hybrid structures are covered by both of the topics.The proceedings have been selected for coverage in: OCo Index to Scientific & Technical Proceedings (ISTP CDROM version / ISI Proceedings)"

This book introduces the reader to drug delivery with specific emphasis on the use of nanoparticles. It covers properties, characterization, and preparation of different types of nanoparticles and discusses recent advances in their structural design and biomedical application, as well as the issues and challenges associated with their design and use. Some of the topics covered include the potential application of nanoparticles in biomedical fields, hazards associated with use of nanoparticles for drug delivery, size-dependent factors in drug delivery applications, different organic, inorganic and their hybrid systems used in drug delivery, etc. It also highlights use of nanoparticles in controlled and targeted drug delivery, and their application in stimuli-responsive, especially pH-responsive, drug release. Additionally, it also focuses on biomimetic nanoparticles, challenges faced in the designing of nanoparticles for drug delivery in cancer, viral and bacterial diseases. The contents of this volume will be useful to researchers and professionals working on advances in targeted drug delivery systems.

In the vast tapestry of the universe, the subatomic realm stands as a breathtakingly intricate mosaic of mysteries and wonders. As we embark on our journey into the heart of the Quantum Frontier, we are poised to unravel the enigmatic fabric of reality, where the rules governing the subatomic particles defy our classical intuition and beckon us into a realm of uncharted exploration. At the dawn of the 20th century, a revolution was ignited by the pioneers of quantum physics. These visionary scientists, armed with insatiable curiosity and unwavering determination, delved into the subatomic world with intellectual fervor, challenging the very foundations of classical physics. From Max Planck's quantization of energy to Albert Einstein's elucidation of the photoelectric effect, their groundbreaking contributions set the stage for a profound paradigm shift that would reshape the trajectory of modern science.