Quantum mechanics is now one of the most successful of all known physical theories. Not only have there been innumerable tests of the theory, all confirming its essential correctness; equally convincing is that our world is dominated by devices that function because of the knowledge of the quantum world. Well-known examples include lasers, transistors, magnetic imaging devices and nuclear energy.
Quantum mechanics is now one of the most successful of all known physical theories. Not only have there been innumerable tests of the theory, all confirming its essential correctness; equally convincing is that our world is dominated by devices that function because of the knowledge of the quantum world. Well-known examples include lasers, transistors, magnetic imaging devices and nuclear energy.
Quantum theory is perhaps the theory with the greatest predictive and explanatory success in all the history of physics. To name just a few of its countless achievements: it explains the stability of the stable atoms and nuclei and predicts the decay rates of the unstable ones; it accounts for the different manifestations of matter such as gaseous, liquid and solid, metallic and insulating, magnetic, superfluid and superconducting; it forms the basis of our chemical knowledge; and it provides the conceptual framework of all contemporary models for the fundamental constituents of matter. In addition, some of its predictions, for example that of the ‘electron spin g -factor’ in quantum electrodynamics, are perhaps the most accurate ones ever made in the history of science. Some of its predictions concern matter at extremely high energy and interactions between bits of matter at extremely short distances; others are about matter at extremely low energy and close to the zero of absolute temperature. As far as its technological applications are concerned, its insights are at the heart of the overwhelming technological progress in information technology in the past few decades, it explains why nuclear fission and fusion work as they do, and it forms the basis of the rapidly growing field of nanotechnology. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
Quantum physics is the most successful description of the physical world we live in. Quantum theoretical predictions have been experimentally tested and confirmed up to the astonishing 14 digits of precision in terms of the anomalous magnetic moment of the electron. The bra-ket notation, composed of angle brackets and vertical bars, enhances the clarity of mathematical operations and improves the comprehension of quantum mechanical expressions. Quantum wave functions participate in interference phenomenona in which two waves superpose to form a resultant wave of greater, lower, or the same amplitude. When a quantum system is measured, it undergoes indeterministic transition that actualizes only one of the states from the set of all physically possible future states of the system. The Hilbert vector space structure of the space of quantum states follows from the linearity of the Schrodinger equation. The quantum state vector and the quantum wave function in a Hilbert space are abstract mathematical concepts that are basis independent.
The turn of the XXth century witnessed a revolution in physics comparable to Isaac Newton’s discovery of the universal laws of mechanics and of gravitation three centuries earlier. The world required to be described in novel terms, as the immutable, deterministic view of our familiar universe had given way to a new world picture, one which featured chance, flux, and an incessant upsurge of waves of matter. Such a worldview was so radically new and counterintuitive that it gave rise to strong debates, to the effect that Albert Einstein himself tried to oppose it on the grounds that “God does not play dice”. In spite of the intense debates that accompanied its emergence, quantum mechanics quickly proved an incredibly efficacious new tool to understand and to predict a wide array of new phenomena. It was so successful that in no time it broke free from the environment of research labs to become part of daily life, making it possible, for example, to understand why some materials were conductors, while others were insulators. Along with it, came, too, the discovery of transistors, on which much of modern electronics rests. It also led to understand how novel materials known as superconductors allow the transport of electricity with no loss, thus paving the way for new developments in the fields of medical imagery or energy distribution. Other aspects of the quantum theory led to the development of atomic clocks of astounding accuracy, which would be wrong by no more than fifteen seconds, had they been set at the beginning of the universe. A hundred years later, at the turn of the XXIst century, Quantum mechanics has lost none of its astounding power. Contemporary research has undertaken the task of exploring its less immediately perceptible aspects. Groundbreaking developments have ensued, such as the teleportation of grains of light or the possibility, once predicted by the great physicist Richard Feynman, to build, one day, novel computers which, unlike the ones we are familiar with today, will be able to process innumerable numbers of operations in parallel. The Wright Colloquium will be for us the occasion to explore, in the company of five internationallyknown specialists in the field, some of the fascinating aspects of quantum mechanics. We will appraise how efficiently quantum physics can describe our world, and confront its limitation when it is faced with the infinitely small (in relation to recent experiments carried out at the CERN) as with the incommensurably large scale of sidereal spaces. We will appreciate the extent to which quantum physics already has impacted our everyday lives, and evoke the way in which novel fields such as quantum computers and quantum information will entail profound changes in the future. The quantum adventure has only just begun! Monday 15 November 2010 - 18h30 Jochen Mannhart Center for Electronic Correlations and Magnetism, University of Augsburg, Germany Quantum Physics on the Scale of Daily Life Tuesday 16 November 2010 - 18h30 Wolfgang Ketterle Nobel Laureate 2001 (Physics), Department of Physics, Massachusetts Institute of Technology, Cambridge, U.S.A. When freezing cold is not cold enough New forms of matter close to absolute zero temperature Wednesday 17 November 2010 - 18h30 David Gross Nobel Laureate 2004 (Physics), Kavli Institute for Theoretical Physics, University of California, Santa-Barbara, U.S.A. Quantum Mechanics of the Very, Very Small and the Very, Very Large Thursday 18 November 2010 - 18h30 Alain Aspect CNRS senior scientist and Professor Institut d'Optique and Ecole Polytechnique Palaiseau, France. From Einstein’s intuition to quantum bits: a new quantum age? Vendredi 19 novembre 2010 - 18h30 Rainer Blatt Institute of Quantum Optics and Quantum Information, Austrian Academy of Sciences and University of Innsbruck, Austria The Quantum Way of Doing Computations
Quantum mechanics works exceedingly well in all practical applications. No example of conflict between its predictions and experiment is known. Without quantum physics we could not explain the behavior of solids, the structure and function of DNA, the color of the stars, the action of lasers or the properties of superfluids. Yet well over half a century after its inception, the debate about the relation of quantum mechanics to the familiar physical world continues. How can a theory that can account ith precision for everything we can measure still be deemed lacking?
Quantum mechanics is our most successful physical theory. It underlies our very detailed understanding of atomic physics, chemistry, and nuclear physics, and the many technologies to which physical systems in these regimes give rise. Additionally, relativistic quantum mechanics is the basis for the standard model of elementary particles, which very successfully gives a partial unification of the forces operating at the atomic, nuclear, and subnuclear levels. However, from its inception the probabilistic nature of quantum mechanics, and the fact that “quantum measurements” in the orthodox formulation appear to require the intervention of non-quantum mechanical “classical systems,” have led to speculations by many physicists, mathematicians, and philosophers of science that quantum mechanics may be incomplete. Among the Founding Fathers of quantum theory, Einstein and Schrödinger were both of the opinion that quantum mechanics is in some way unsatisfactory, and this view has been amplified in more recent profound work of John Bell, among others. In an opposing camp, many others in the physics, mathematics, and philosophy communities have attempted to provide an interpretational foundation in which quantum mechanics remains a complete and self-contained system. Among the Founding Fathers, Bohr, Born, and Heisenberg maintained that quantum mechanics is a complete system, and a number of recent proposals have been made to improve upon or to provide alternatives to their “Copenhagen Interpretation.” The debate continues, and has spawned an enormous literature.
This book provides a first course on quantum mechanics and describes simple applications to physical phenomena that are of immediate and everyday interest. The first five chapters introduce the fundamentals of quantum mechanics and are followed by a revision quiz with which readers may test their understanding. The remaining chapters describe applications, including the physics of lasers, molecular binding, simple properties of crystalline solids arising from their band structure, and the operation of junction transistors. This new edition (first edition entitled Simple Quantum Physics) has been expanded to include a chapter on the theory of spin and its application to magnetic resonance imaging, as well as a description of the WKB approximation and its application to alpha decay. Ideal either as a course text or a self-study text, the book contains nearly 100 exercises and hints to their solution.