Traditional courses in quantum mechanics teach students how to use the quantum formalism to make calculations. But even the best students - indeed, especially the best students - emerge rather confused about what, exactly, the theory says is going on, physically, in microscopic systems. This supplementary textbook is designed to help such students understand that they are not alone in their confusions (luminaries such as Albert Einstein, Erwin Schroedinger, and John Stewart Bell having shared them), to sharpen their understanding of the most important difficulties associated with interpreting quantum theory in a realistic manner, and to introduce them to the most promising attempts to formulate the theory in a way that is physically clear and coherent.The text is accessible to students with at least one semester of prior exposure to quantum (or "modern") physics and includes over a hundred engaging end-of-chapter "Projects" that make the book suitable for either a traditional classroom or for self-study.

    Albert Einstein may have died decades ago, but his immense legacy continues. Who has not heard of Einstein’s theory of relativity, which revolutionized our understanding of space, time, and matter? His other discoveries are themselves titanic achievements that on their own would have made him a famous scientist.But Einstein was not infallible. He rejected the possibility of black holes, and he was reluctant to accept the concept of an expanding universe or that gravity waves might exist. All are predicted by his general theory of relativity, and all have been well confirmed by observations. Furthermore, he was practically alone among his peers in resisting the startling implications of quantum mechanics—a theory that he helped found and whose strange picture of reality has been verified in experiment after experiment.In other words, what Einstein got wrong includes some of the most exciting science of our time.In a course aimed at the scientifically curious at all levels, What Einstein Got Wrong focuses on the great scientist’s mistakes as a window into his mind—his thought processes, prejudices, and philosophical outlook. Studying Einstein’s errors may well be the best way of getting inside the head of this incomparable and enigmatic thinker, who was so influential that Time magazine named him the Person of the Century in 1999.Your professor on this thrilling intellectual journey is Dr. Dan Hooper, a researcher at the forefront of physics and a popular author and speaker on particle physics and cosmology. Dr. Hooper is Senior Scientist at the Fermi National Accelerator Laboratory, and Associate Professor of Astronomy and Astrophysics at the University of Chicago.In twelve half-hour lectures, Dr. Hooper discusses Einstein’s ideas—right and wrong—using minimal mathematics, so it’s accessible to curious minds everywhere. Those new to Einstein’s ideas will find What Einstein Got Wrong an excellent survey of the full scope of the master’s work, while those more experienced with physics and relativity will relish Dr. Hooper’s insights into Einstein’s legacy in modern physics, which lives on in myriad ways. Even Einstein’s mistakes inspired others along productive paths.Einstein Invents Relativity but Doesn’t Fully Buy ItYou begin with a two-lecture review of what Einstein got spectacularly right, notably his special and general theories of relativity. Proposed in 1905, special relativity introduced such concepts as the constancy of the speed of light, the relativity of simultaneity, time dilation, and the equivalence of mass and energy. General relativity, published a decade later, greatly enlarged the scope of special relativity by incorporating gravity, which Einstein showed is a geometric property of space and time.Special relativity created a sensation among Einstein’s fellow scientists, but general relativity made him world-famous, giving him a reputation as a scientific magician. That reputation stuck, and only his colleagues appreciated the setbacks that dogged him throughout his career as he struggled to develop and interpret his theories:The relativity race: Einstein had the conceptual pieces of general relativity in place long before he worked out the mathematical details. Unwittingly abandoning a promising path to a definitive theory, he suddenly discovered he was in a race with the world’s foremost mathematician, who was working on his own formulation of general relativity. Einstein barely won.Black holes banned: The first meaningful solution to Einstein’s equations of general relativity were worked out by mathematician Karl Schwarzschild, whose calculations showed the possibility of infinitely dense objects, later dubbed black holes. Einstein held that natural forces would prevent such bizarre phenomena, and his influence long persuaded other physicists that black holes were impossible.His “biggest blunder”: Convinced that the universe is static and eternal, Einstein added a cosmological constant to his formula for general relativity to forestall the instability his theory predicted. When astronomer Edwin Hubble discovered that the universe is expanding—that is, it’s unstable—Einstein reportedly called the constant his “biggest blunder.”Einstein Fights the Quantum RevolutionAlong with relativity, the other great revolution in physics in the 20th century was quantum mechanics. Einstein led the way here too, by proving the particle nature of light and that atoms really exist. As with relativity, he was wary of accepting the full implications of the developing theory:“God does not play dice”: Experiments showed that matter behaves very strangely at the quantum scale. Einstein’s friend Max Born proposed that the traditional view of cause and effect does not apply in quantum mechanics, where interactions can only be understood in terms of probabilities. Einstein dismissed this view with the remark, “God does not play dice with the universe.”Schrödinger's cat: Working with colleagues Boris Podolsky and Nathan Rosen, Einstein devised a thought experiment that showed an apparent impossibility in a quantum state later called entanglement. This was the inspiration for Erwin Schrödinger's famous paradox involving a cat that is simultaneously dead and alive. But impossible or not, entanglement turns out to be real.Unified field theory: Inspired by James Clerk Maxwell’s unification of electrical and magnetic phenomena in a single theory called electromagnetism, Einstein sought to do the same for electromagnetism and relativity. His hope was that this “unified field theory” would restore determinism and scientific realism to the quantum world. But his labors were fruitless.Dr. Hooper stresses that Einstein’s miscalculations, oversights, and false leads do not detract from his greatness. In the final lecture, he points out how missteps also plagued the careers of Johannes Kepler, Galileo Galilei, and Isaac Newton—three other indisputable giants in the history of science.Indeed, mistakes are fundamental to scientific progress. One of Einstein’s colleagues at Princeton University, the physicist John Wheeler, observed that “our whole problem is to make mistakes as fast possible.” Only by priming the pump with theories that can be tested against evidence do we advance closer to the truth, throwing out the bad theories and improving the good. The beauty of science is not that it is infallible but that it corrects its mistakes. Einstein was a ceaselessly creative participant in this process, as you learn in What Einstein Got Wrong.

    But we have yet to understand the revolution's significance for philosophy. Richard Healey opens a path to such understanding. Most studies of the conceptual foundations of quantum theory first try to interpret the theory - to say how the worldcould possibly be the way the theory says it is. But, though fundamental, quantum theory is enormously successful without describing the world in its own terms. When properly applied, models of quantum theory offer good advice on the significance and credibility of claims about the world expressedin other terms. This first philosophical lesson of the quantum revolution dissolves the quantum measurement problem. Pragmatist treatments of probability and causation show how quantum theory may be used to explain the non-localized correlations that have been thought to involve spookyinstantaneous action at a distance. Given environmental decoherence, a pragmatist inferentialist approach to content shows when talk of quantum probabilities is licensed, resolves any residual worries about whether a quantum measurement has a determinate outcome, and solves a dilemma about theontology of a quantum field theory. This approach to meaning and reference also reveals the nature and limits of objective description in the light of quantum theory. While these pragmatist approaches to probability, causation, explanation and content may be independently motivated by philosophicalargument, their successful application here illustrates their practical importance in helping philosophers come to terms with the quantum revolution.