This book explains, in simple terms, with a minimum of mathematics, why things can appear to be in two places at the same time, why correlations between simultaneous events occurring far apart cannot be explained by local mechanisms, and why, nevertheless, the quantum theory can be understood in terms of matter in motion. No need to worry, as some people do, whether a cat can be both dead and alive, whether the moon is there when nobody looks at it, or whether quantum systems need an observer to acquire definite properties. The author’s inimitable and even humorous style makes the book a pleasure to read while bringing a new clarity to many of the longstanding puzzles of quantum physics.

Quantum theory is perhaps our best confirmed theory for a description of the physical properties of nature. On top of demonstrating great empirical effectiveness, many technological developments in the 20th century (such as the interpretation of the periodic table of elements, CD players, holograms, and quantum state teleportation) were only made possible with Quantum theory.Despite its success in the past decades, even today it still remains without a universally accepted interpretation.This book provides an interdisciplinary perspective on the question; 'What is Quantum Mechanics talking about?', a question which continues to be one of the most fascinating and important questions in science.Using an interdisciplinary approach to foundational problems in Quantum Mechanics (QM), ranging from philosophical questions about the interpretation of QM to technical problems in quantum computation, this book explores quantum mechanics from different perspectives (physical, logical, philosophical and mathematical), by researchers from Europe, North America, and South America.

This book provides an interdisciplinary perspective on one of the most fascinating and important open questions in science: What is quantum mechanics talking about? Quantum theory is perhaps our best confirmed physical theory. However, despite its great empirical effectiveness and the subsequent technological developments that it gave rise to in the 20th century, from the interpretation of the periodic table of elements to CD players, holograms and quantum state teleportation, it stands even today without a universally accepted interpretation. The novelty of the book comes from the multiple viewpoints and subjects investigated by a group of researchers from Europe and North and South America.

'The authors should be recognised for their efforts to present a mathematically rigorous introduction to Quantum Mechanics (QM) in a form that has broad appeal; there are not many introductory QM texts that would cover, for example, decoherence. I think many educators would appreciate this book, especially those interested in courses that combine science and philosophy.'Contemporary PhysicsApart from providing a lucid introduction to the mathematical formalism and conceptual foundations of quantum mechanics, we explain why the laws of physics have the form that they do. In addition, we present a new and unique look at the quantum world, steering clear of two common errors: the error of the ψ-ontologists, who reify a calculational tool; and the error of the anti-realists, for whom physical theories are simply devices for expressing regularities among observations.The new edition of this acclaimed text adds around 200 pages on a variety of topics, such as how the founders sought to make sense of quantum mechanics, Kant's theory of science, QBism, Everettian quantum mechanics, de Broglie-Bohm theory, environmental decoherence, contextuality, nonlocality, and the paradox of subjectivity — the curious fact that the world seems to exist twice, once for us, in our minds, and once by itself, independently of us.

This Volume 1 of Part II considers the factors that make science progress. It lays out the differences between normal science and pseudoscience by showing the importance of the scientific method in the advancement of science. It introduces the concept of Truth in science by raising the point that even though truth is based on the scientific method, can science be true? Can it depict reality? The author focuses on modern science, which, he thinks, was born thanks to the Scientific Revolution which started with Galileo Galilei and led to the Industrial Revolution. The impacts of the latter is analyzed in light modernism, modernization, and modernity, all three linked to scientific progress. The book also talks about the Newtonian scientific leap – by analyzing particularly the then social and political fabrics of England – and Albert Einstein by showing how he changed history. According to the author, our very physical world can help us understand scientific progress. So, he explains, among other things, the structure of atoms and molecules, the role of physics in the understanding of our universe, Quantum Mechanics, and the importance of Higgs-Boson. On the other hand, the book is a stunning revelation of how important information is to scientific progress. To make his point, the author, first, talks about John Vincent Atanasoff as the Father of computer thanks to the invention of his ABC computer and then, Alan Turing as the Father of modern computer thanks to his Turing Test and his views on Artificial Intelligence. Both men played a momentous role in the Digital Revolution and in the Information Age, according to the book. Finally, the author talks about nanotechnology, which explores the world of small, meaning at the atomic and the molecular levels and is an inescapable tool in the molecular biology revolution which, itself, is an important factor in scientific progress and in transhumanism or human enhancement defined as the ideology according to which man can surpass his present state by improving his genetic material.

These were my personal lecture notes for the Fall 2010, University of Toronto Quantum mechanics I course (PHY356H1F), taught by Prof. Vatche Deyirmenjian. The official description of this course was: The general structure of wave mechanics; eigenfunctions and eigenvalues; operators; orbital angular momentum; spherical harmonics; central potential; separation of variables, hydrogen atom; Dirac notation; operator methods; harmonic oscillator and spin. This document contains a few things • My lecture notes. Typos, if any, are probably mine(Peeter), and no claim nor attempt of spelling or grammar correctness will be made. The first four lectures had chosen not to take notes for since they followed the text very closely. • Notes from reading of the text. This includes observations, notes on what seem like errors, and some solved problems. None of these problems have been graded. Note that my informal errata sheet for the text has been separated out from this document. • Some assigned problems. I have corrected some the errors after receiving grading feedback, and where I have not done so I at least recorded some of the grading comments as a reference. • Some worked problems associated with exam preparation.

From Spinors to Quantum Mechanics discusses group theory and its use in quantum mechanics. Chapters 1 to 4 offer an introduction to group theory, and it provides the reader with an exact and clear intuition of what a spinor is, showing that spinors are just a mathematically complete notation for group elements. Chapter 5 contains the first rigorous derivation of the Dirac equation from a simple set of assumptions. The remaining chapters will interest the advanced reader who is interested in the meaning of quantum mechanics. They propose a novel approach to the foundations of quantum mechanics, based on the idea that the meaning of the formalism is already provided by the mathematics.In the traditional approach to quantum mechanics as initiated by Heisenberg, one has to start from a number of experimental results and then derive a set of rules and calculations that reproduce the observed experimental results. In such an inductive approach the underlying assumptions are not given at the outset. The reader has to figure them out, and this has proven to be difficult. The book shows that a different, bottom-up approach to quantum mechanics is possible, which merits further investigation as it demonstrates that with the methods used, the reader can obtain the correct results in a context where one would hitherto not expect this to be possible.

This book discusses the physical and mathematical foundations of modern quantum mechanics and three realistic quantum theories that John Stuart Bell called "theories without observers" because they do not merely speak about measurements but develop an objective picture of the physical world. These are Bohmian mechanics, the GRW collapse theory, and the Many Worlds theory. The book is ideal to accompany or supplement a lecture course on quantum mechanics, but also suited for self-study, particularly for those who have completed such a course but are left puzzled by the question: "What does the mathematical formalism, which I have so laboriously learned and applied, actually tell us about nature?”

Many people, including physicists, are confused about what the Second Law of thermodynamics really means, about how it relates to the arrow of time, and about whether it can be derived from classical mechanics. They also wonder what entropy really is: Is it all about information? But, if so, then, what is its relation to fluxes of heat? One might ask similar questions about probabilities: Do they express subjective judgments by us, humans, or do they reflect facts about the world, i.e. frequencies. And what notion of probability is used in the natural sciences, in particular statistical mechanics? This book addresses all of these questions in the clear and pedagogical style for which the author is known. Although valuable as accompaniment to an undergraduate course on statistical mechanics or thermodynamics, it is not a standard course book. Instead it addresses both the essentials and the many subtle questions that are usually brushed under the carpet in such courses. As one of the most lucid accounts of the above questions, it provides enlightening reading for all those seeking answers, including students, lecturers, researchers and philosophers of science.