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.

Named a Best Book of 2021 by the Financial Times and a Best Science Book of 2021 by The Guardian “Rovelli is a genius and an amazing communicator… This is the place where science comes to life.” ―Neil Gaiman “One of the warmest, most elegant and most lucid interpreters to the laity of the dazzling enigmas of his discipline...[a] momentous book” ―John Banville, The Wall Street Journal A startling new look at quantum theory, from the New York Times bestselling author of Seven Brief Lessons on Physics, The Order of Time, and Anaximander. One of the world's most renowned theoretical physicists, Carlo Rovelli has entranced millions of readers with his singular perspective on the cosmos. In Helgoland, he examines the enduring enigma of quantum theory. The quantum world Rovelli describes is as beautiful as it is unnerving. Helgoland is a treeless island in the North Sea where the twenty-three-year-old Werner Heisenberg made the crucial breakthrough for the creation of quantum mechanics, setting off a century of scientific revolution. Full of alarming ideas (ghost waves, distant objects that seem to be magically connected, cats that appear both dead and alive), quantum physics has led to countless discoveries and technological advancements. Today our understanding of the world is based on this theory, yet it is still profoundly mysterious. As scientists and philosophers continue to fiercely debate the meaning of the theory, Rovelli argues that its most unsettling contradictions can be explained by seeing the world as fundamentally made of relationships rather than substances. We and everything around us exist only in our interactions with one another. This bold idea suggests new directions for thinking about the structure of reality and even the nature of consciousness. Rovelli makes learning about quantum mechanics an almost psychedelic experience. Shifting our perspective once again, he takes us on a riveting journey through the universe so we can better comprehend our place in it.

'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.

"A thorough, illuminating exploration of the most consequential controversy raging in modern science." --New York Times Book Review An Editor's Choice, New York Times Book Review Longlisted for PEN/E.O. Wilson Prize for Literary Science Writing Longlisted for Goodreads Choice Award Every physicist agrees quantum mechanics is among humanity's finest scientific achievements. But ask what it means, and the result will be a brawl. For a century, most physicists have followed Niels Bohr's solipsistic and poorly reasoned Copenhagen interpretation. Indeed, questioning it has long meant professional ruin, yet some daring physicists, such as John Bell, David Bohm, and Hugh Everett, persisted in seeking the true meaning of quantum mechanics. What Is Real? is the gripping story of this battle of ideas and the courageous scientists who dared to stand up for truth. "An excellent, accessible account." --Wall Street Journal "Splendid. . . . Deeply detailed research, accompanied by charming anecdotes about the scientists." --Washington Post

“Anyone who is not shocked by quantum theory has not understood it.” Since Niels Bohr said this many years ago, quantum mechanics has only been getting more shocking. We now realize that it’s not really telling us that “weird” things happen out of sight, on the tiniest level, in the atomic world: rather, everything is quantum. But if quantum mechanics is correct, what seems obvious and right in our everyday world is built on foundations that don’t seem obvious or right at all—or even possible. An exhilarating tour of the contemporary quantum landscape, Beyond Weird is a book about what quantum physics really means—and what it doesn’t. Science writer Philip Ball offers an up-to-date, accessible account of the quest to come to grips with the most fundamental theory of physical reality, and to explain how its counterintuitive principles underpin the world we experience. Over the past decade it has become clear that quantum physics is less a theory about particles and waves, uncertainty and fuzziness, than a theory about information and knowledge—about what can be known, and how we can know it. Discoveries and experiments over the past few decades have called into question the meanings and limits of space and time, cause and effect, and, ultimately, of knowledge itself. The quantum world Ball shows us isn’t a different world. It is our world, and if anything deserves to be called “weird,” it’s us.

Permeated by the author's delightful humor, this little book explains, with nearly no mathematics, the main conceptual issues associated with quantum mechanics: The issue of determinism. Does quantum mechanics signify the end of a deterministic word-view? The role of the human subject or of the "observer" in science. Since Copernicus, science has increasingly tended to dethrone Man from his formerly held special position in the Universe. But quantum mechanics, with its emphasis on the notion of observation, may once more have given a central role to the human subject. The issue of locality. Does quantum mechanics imply that instantaneous actions at a distance exist in Nature? In these pages the author offers a variety of views and answers - bad as well as good - to these questions. The reader will be both entertained and enlightened by Jean Bricmont's clear and incisive arguments.

Philosophy of physics is concerned with the deepest theories of modern physics - quantum theory, our theories of space, time and symmetry, and thermal physics - and their strange, even bizarre conceptual implications. This book explores the core topics in philosophy of physics, and discusses their relevance for both scientists and philosophers.

From the bestselling author of The Theoretical Minimum, a DIY introduction to the math and science of quantum physics First he taught you classical mechanics. Now, physicist Leonard Susskind has teamed up with data engineer Art Friedman to present the theory and associated mathematics of the strange world of quantum mechanics. In this follow-up to The Theoretical Minimum, Susskind and Friedman provide a lively introduction to this famously difficult field, which attempts to understand the behavior of sub-atomic objects through mathematical abstractions. Unlike other popularizations that shy away from quantum mechanics’ weirdness, Quantum Mechanics embraces the utter strangeness of quantum logic. The authors offer crystal-clear explanations of the principles of quantum states, uncertainty and time dependence, entanglement, and particle and wave states, among other topics, and each chapter includes exercises to ensure mastery of each area. Like The Theoretical Minimum, this volume runs parallel to Susskind’s eponymous Stanford University-hosted continuing education course. An approachable yet rigorous introduction to a famously difficult topic, Quantum Mechanics provides a tool kit for amateur scientists to learn physics at their own pace.

Authored by an acclaimed teacher of quantum physics and philosophy, this textbook pays special attention to the aspects that many courses sweep under the carpet. 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.

Metaphysicians should pay attention to quantum mechanics. Why? Not because it provides definitive answers to many metaphysical questions-the theory itself is remarkably silent on the nature of the physical world, and the various interpretations of the theory on offer present conflicting ontological pictures. Rather, quantum mechanics is essential to the metaphysician because it reshapes standard metaphysical debates and opens up unforeseen new metaphysical possibilities. Even if quantum mechanics provides few clear answers, there are good reasons to think that any adequate understanding of the quantum world will result in a radical reshaping of our classical world-view in some way or other. Whatever the world is like at the atomic scale, it is almost certainly not the swarm of particles pushed around by forces that is often presupposed. This book guides readers through the theory of quantum mechanics and its implications for metaphysics in a clear and accessible way. The theory and its various interpretations are presented with a minimum of technicality. The consequences of these interpretations for metaphysical debates concerning realism, indeterminacy, causation, determinism, holism, and individuality (among other topics) are explored in detail, stressing the novel form that the debates take given the empirical facts in the quantum domain. While quantum mechanics may not deliver unconditional pronouncements on these issues, the range of possibilities consistent with our knowledge of the empirical world is relatively small-and each possibility is metaphysically revisionary in some way. This book will appeal to researchers, students, and anybody else interested in how science informs our world-view.