The sounds of science—a symphony for many instruments and voices: part II

Despite its amazing quantitative successes and contributions to revolutionary technologies, physics currently faces many unsolved mysteries ranging from the meaning of quantum mechanics to the nature of the dark energy that will determine the future of the Universe. It is clearly prohibitive for the general reader, and even the best informed physicists, to follow the vast number of technical papers published in the thousands of specialized journals. For this reason, we have asked the leading experts across many of the most important areas of physics to summarise their global assessment of some of the most important issues. In lieu of an extremely long abstract summarising the contents, we invite the reader to look at the section headings and their authors, and then to indulge in a feast of stimulating topics spanning the current frontiers of fundamental physics from ‘The Future of Physics’ by William D Phillips and ‘What characterises topological effects in physics?’ by Gerard ’t Hooft through the contributions of the widest imaginable range of world leaders in their respective areas. This paper is presented as a preface to exciting developments by senior and young scientists in the years that lie ahead, and a complement to the less authoritative popular accounts by journalists

The quantum story: a history in 40 moments

The twentieth century was defined by physics. From the minds of the world's leading physicists there flowed a river of ideas that would transport mankind to the pinnacle of wonderment and to the very depths of human despair. This was a century that began with the certainties of absolute knowledge and ended with the knowledge of absolute uncertainty. It was a century in which physicists developed weapons with the capacity to destroy our reality, whilst at the same time denying us thepossibility that we can ever properly comprehend it. Almost everything we think we know about the nature of our

Mass: the quest to understand matter from Greek atoms to quantum fields

Everything around us is made of 'stuff', from planets, to books, to our own bodies. Whatever it is, we call it matter or material substance. It is solid; it has mass. But what is matter, exactly? We are taught in school that matter is not continuous, but discrete. As a few of the philosophers of ancient Greece once speculated, nearly two and a half thousand years ago, matter comes in 'lumps', and science has relentlessly peeled away successive layers of matter to reveal its ultimate constituents. Surely, we can't keep doing this indefinitely. We imagine that we should eventually run up against some kind of ultimately fundamental, indivisible type of stuff, the building blocks from which everything in the Universe is made. The English physicist Paul Dirac called this 'the dream of philosophers'. But science has discovered that the foundations of our Universe are not as solid or as certain and dependable as we might have once imagined. They are instead built from ghosts and phantoms, of a peculiar quantum kind. And, at some point on this exciting journey of scientific discovery, we lost our grip on the reassuringly familiar concept of mass. How did this happen? How did the answers to our questions become so complicated and so difficult to comprehend? In Mass Jim Baggott explains how we come to find ourselves here, confronted by a very different understanding of the nature of matter, the origin of mass, and its implications for our understanding of the material world. Ranging from the Greek philosophers Leucippus and Democritus, and their theories of atoms and void, to the development of quantum field theory and the discovery of a Higgs boson-like particle, he explores our changing understanding of the nature of matter, and the fundamental related concept of mass.Jim Baggott explores how our understanding of the nature of matter, and its fundamental property of mass, has developed, from the ancient Greek view of indivisible atoms to quantum mechanics, dark matter, the Higgs field, and beyond. He shows how the stuff of the universe is proving more elusive and uncertain than we ever imagined

La particule de Dieu: à la découverte du boson de Higgs

De quoi le monde est-il constitué? Des questions aussi simples que celle-ci ont taraudé l'esprit de l'Homme depuis les origines. Même si les raisonnements sont devenus de plus en plus complexes au fil du temps, au fond, cette question centrale reste très basique. Ce livre raconte la quête des scientifiques pour élaborer un modèle permettant d'expliquer la structure de la matière à son niveau le plus élémentaire, jusqu'à l'annonce de la découverte du fameux boson de Higgs, au LHC, le 4 juillet 2012. Qu'est-ce que le boson de Higgs et en quoi sa découverte est-elle si importante? La réponse à cette question réside dans l'histoire du modèle standard de la physique des particules. Ce modèle, élaboré découverte après découverte, depuis le début du XXe siècle, recense toutes les particules constitutives de l'univers. Il prédisait jusqu'ici l'existence d'un champs dit de Higgs indispensable pour donner leur masse aux autres particules du modèle. Sans le boson de Higgs, l'univers ne pouvait tout simplement pas être ce qu'il est

Quantum space: loop quantum gravity and the search for the structure of space, time, and the universe

Today we are blessed with two extraordinarily successful theories of physics. The first is Albert Einstein's general theory of relativity, which describes the large-scale behaviour of matter in a curved spacetime. This theory is the basis for the standard model of big bang cosmology. The discovery of gravitational waves at the LIGO observatory in the US (and then Virgo, in Italy) is only the most recent of this theory's many triumphs. The second is quantum mechanics. This theory describes the properties and behaviour of matter and radiation at their smallest scales. It is the basis for the standard model of particle physics, which builds up all the visible constituents of the universe out of collections of quarks, electrons and force-carrying particles such as photons. The discovery of the Higgs boson at CERN in Geneva is only the most recent of this theory's many triumphs. But, while they are both highly successful, these two structures leave a lot of important questions unanswered. They are also based on two different interpretations of space and time, and are therefore fundamentally incompatible. We have two descriptions but, as far as we know, we've only ever had one universe. What we need is a quantum theory of gravity. Approaches to formulating such a theory have primarily followed two paths. One leads to String Theory, which has for long been fashionable, and about which much has been written. But String Theory has become mired in problems. In this book, Jim Baggott describes "the road less travelled": an approach which takes relativity as its starting point, and leads to a structure called Loop Quantum Gravity. Baggott tells the story through the careers and pioneering work of two of the theory's most prominent contributors, Lee Smolin and Carlo Rovelli. Combining clear discussions of both quantum theory and general relativity, this book offers one of the first efforts to explain the new quantum theory of space and time.The greatest challenge for physics is to combine its two most successful theories: general relativity and quantum mechanics. The resulting quantum theory of gravity would explain the universe across all scales. Much has been said about the approach based on string theory. Here, Jim Baggott describes its powerful rival: Loop Quantum Gravity

The quantum cookbook: mathematical recipes for the foundations for quantum mechanics

This work combines popular exposition and textbook presentation. It aims not to teach readers how to do quantum mechanics but rather helps them understand how to think about quantum mechanics. The real source of confusion in quantum mechanics does not originate in the mathematics, but in our understanding of what a scientific theory is supposed to represent

Origins: the scientific story of creation

What is the nature of the material world? How does it work? What is the universe and how was it formed? What is life? Where do we come from and how did we evolve? How and why do we think? What does it mean to be human? How do we know? There are many different versions of our creation story. This book tells the version according to modern science. It is a unique account, starting at the Big Bang and travelling right up to the emergence of humans as conscious intelligent beings, 13.8 billion years later. Chapter by chapter, it sets out the current state of scientific knowledge: the origins of space and time; energy, mass, and light; galaxies, stars, and our sun; the habitable earth, and complex life itself. Drawing together the physical and biological sciences, Baggott recounts what we currently know of our history, highlighting the questions science has yet to answer.What is the nature of the material world? How does it work? What is the universe and how was it formed? What is life? Where do we come from and how did we evolve? How and why do we think? What does it mean to be human? How do we know?There are many different versions of our creation story. This book tells the version according to modern science. It is a unique account, starting at the Big Bang and travelling right up to the emergence of humans as conscious intelligent beings, 13.8 billion years later. Chapter by chapter, it sets out the current state of scientific knowledge: the origins of spaJim Baggott sets out the scientific story of creation - 13.8 billion years from the Big Bang to human consciousness, via the origins of space and time, mass and light, stars, the habitable earth, and life itself. From astrophysics to biology, the whole inspiring picture is here.Jim Baggott sets out the scientific story of creation - 13.8 billion years from the Big Bang to human consciousness, via the origins of space and time, mass and light, stars, the habitable earth, and life itself. From astrophysics to biology, the whole inspiring picture is here

Higgs: the invention and discovery of the 'God Particle'

The hunt for the Higgs particle has involved the biggest, most expensive experiment ever. So exactly what is this particle? Why does it matter so much? What does it tell us about the Universe? Has the discovery announced on 4 July 2012 finished the search? And was finding it really worth all the effort? The short answer is yes. The Higgs field is proposed as the way in which particles gain mass - a fundamental property of matter. It's the strongest indicator yet that the Standard Model of physics really does reflect the basic building blocks of our Universe. Little wonder the hunt and discovery of this new particle has produced such intense media interest.The hunt for the Higgs particle has involved the biggest, most expensive experiment ever. So exactly what is this particle? Why does it matter so much? What does it tell us about the Universe? Has the discovery announced on 4 July 2012 finished the search? And was finding it really worth all the effort?The short answer is yes. The Higgs field is proposed as the way in which particles gain mass - a fundamental property of matter. It's the strongest indicator yet that the Standard Model of physics really does reflect the basic building blocks of our Universe. Little wonder the hunt and discover