From Atoms to Higgs Bosons : Voyages in Quasi-Spacetime

For millennia, natural philosophers and scientists have been actively engaged in the reductionist quest to specify the fundamental building blocks of matter and discern the dynamics of physical reality. During the last one hundred years, physicists have intensified this search, probing the deep interior of atoms, nuclei, and the entities of which these are composed. Their progress in this endeavor was highlighted by the announced discovery of the Higgs boson, a watershed moment for particle physics. All of this, however, has come at a cost: an increasingly abstract, inherently mathematical description of nature at its most basic level. This book is an assessment of this cost and critiques the modern orthodoxy that the ever-evolving models of particle physics are leading us towards a truer understanding of the real world. The authors propose that the ancient reductionist quest has been unintentionally side-lined by quasirealism, a philosophical approach to interpreting reductionist scientific models that finds reality hiding in places where it might not actually be. Cover 1 Half Title 2 Tilte Page 4 Copyright Page 5 Dedication 6 Contents 8 Preface 12 Introduction 16 1. The Reductionist Vision of Physics 24 1.1 Reductionism 24 1.2 Our View of the World 25 1.3 Democritus’ Atoms 28 1.4 Properties of Atoms in Early Physics 31 1.5 The Descent into the Quark Model 35 1.6 Contemporary Catalogue of Physical Things 39 1.7 Have We Reached the Bottom? 40 1.8 Defining the Bottom Rung of the Ladder 44 1.9 Are Quarks Really at the Bottom? 46 2. Quasirealism 50 2.1 Common Sense 50 2.2 Mathematics at the Centre 52 2.3 Quasiparticles 54 2.4 Quasirealism Defined 56 2.5 Against Quasirealism 60 2.6 Quasirealism and the Theory of Everything 64 2.7 Concluding Thoughts 66 3. Space, Time, and Relativity 68 3.1 Ancient Concepts of Space and Time 69 3.2 Philosophizing on Space and Time 70 3.3 Newton’s Absolute Space 72 3.4 Lines of Force and Fields 77 3.5 The Aether 82 3.6 Lorentz–FitzGerald Contraction 86 3.7 Special Relativity 87 3.8 General Relativity 90 3.9 Concluding Remarks 94 4. Mathematical Spaces 96 4.1 Space and N-Dimensional Spaces 96 4.2 Space and Geometry 98 4.3 Complex Numbers and Imaginary Planes 103 4.4 Minkowski Spacetime 106 4.5 Phase Space 108 4.6 Hilbert Space 111 4.7 String Theories and Multidimensional Space 113 5. Mass 118 5.1 Mass and Weight 118 5.2 Mass and Relativity 121 5.3 Mass of Small Things 124 5.4 Modern Mass Measurements of Subatomic Particles 127 5.5 Mass of Short-Lived Particles 129 5.6 Mass of Resonances 134 5.7 Mass of Quarks 139 5.8 Mass of Higgs Boson 143 5.9 Concluding Remarks on Mass 145 6. Quantum Physics 148 6.1 Statistical Microphysics and Waves 148 6.2 Quantum Theory of the Atom 150 6.3 What Evolves in Quantum Theory? 153 7. When Is an Atom? 156 7.1 The Classical Atom 156 7.2 The Divisible Chemical Atom 158 7.3 Protons and Neutrons Are Particles, but Are They Fundamental? 160 7.4 The Electron Is Fundamental, but Is It Still a Particle? 162 7.5 The Electron of Wave Mechanics 163 7.6 Niels Bohr’s Instrumentalist View 166 7.7 Electrons in Quantum Electrodynamics 168 7.8 Electrons in Bulk Matter 173 7.9 In Summary: We May Still Have Atoms 177 8. Elementary Quanta 178 8.1 Fermions, Bosons, Quarks, and Leptons 178 8.2 Quarks and Leptons Are Really Very Different 186 8.3 On the Reality of Neutrinos 188 8.4 On the Reality of Quarks 190 8.5 The Gauge Bosons 192 8.6 Summary 195 9. What Is a Photon? 196 9.1 Problem of Blackbody Radiation 197 9.2 Photoelectric Effect 199 9.3 Waves and Particles, Real and Virtual 200 9.4 Other Lives of Photons 205 9.5 Photons and Electroweak Unification 207 9.6 Are Photons Phoenixes? 209 9.7 Finally, What Are Photons? 211 10. Symmetries, Conservation Laws, and Gauge Bosons 214 10.1 Symmetry and Gauge 214 10.2 Gauge Invariance and Electromagnetism 216 10.3 Symmetry and Isospin 217 10.4 Mixing of Matter and Interactions 219 10.5 Conclusion 225 11. Higgs Boson 226 11.1 Knowing What We Cannot See 226 11.2 Searching for the Higgs Boson 227 11.3 Higgs Discovery 236 11.4 Particle or Resonance? 238 11.5 What Does the Higgs Boson Contribute? 240 11.6 Conclusion 243 Epilogue 246 Appendix: Epitaph for All Photons 256 Index 258 The announcement in 2012 that the Higgs boson had been discovered was understood as a watershed moment for the Standard Model of particle physics. It was deemed a triumphant event in the reductionist quest that had begun centuries ago with the ancient Greek natural philosophers. Physicists basked in the satisfaction of explaining to the world that the ultimate cause of mass in our universe had been unveiled at CERN, Switzerland. The Standard Model of particle physics is now understood by many to have arrived at a satisfactory description of entities and interactions on the smallest physical scales: elementary quarks, leptons, and intermediary gauge bosons residing within a four-dimensional spacetime continuum. Throughout the historical journey of reductionist physics, mathematics has played an increasingly dominant role. Indeed, abstract mathematics has now become indispensable in guiding our discovery of the physical world. Elementary particles are endowed with abstract existence in accordance with their appearance in complicated equations. Heisenberg's uncertainty principle, originally intended to estimate practical measurement uncertainties, now bequeaths a numerical fuzziness to the structure of reality. Particle physicists have borrowed effective mathematical tools originally invented and employed by condensed matter physicists to approximate the complex structures and dynamics of solids and liquids and bestowed on them the authority to define basic physical reality. The discovery of the Higgs boson was a result of these kinds of strategies, used by particle physicists to take the latest steps on the reductionist quest. This book offers a constructive critique of the modern orthodoxy into which all aspiring young physicists are now trained, that the ever-evolving mathematical models of modern physics are leading us toward a truer understanding of the real physical world. The authors propose that among modern physicists, physical realism has been largely replaced--in actual practice--by quasirealism, a problematic philosophical approach that interprets the statements of abstract, effective mathematical models as providing direct information about reality. History may judge that physics in the twentieth century, despite its seeming successes, involved a profound deviation from the historical reductionist voyage to fathom the mysteries of the physical universe "For millennia, natural philosophers and scientists have been actively engaged in the reductionist quest to specify the fundamental building blocks of matter and discern the dynamics of physical reality. During the last one hundred years, physicists have intensified this search, probing the deep interior of atoms, nuclei and the entities of which these are composed. Their progress in this endeavour was highlighted by the announced discovery of the Higgs boson, a watershed moment for particle physics. All of this, however, has come at a cost: an increasingly abstract, inherently mathematical description of nature at its most basic level. This book is an assessment of this cost, and a critique of the modern orthodoxy that the ever-evolving models of particle physics are leading us towards a truer understanding of the real world. We propose that the ancient reductionist quest has been unintentionally side-lined by quasirealism, a philosophical approach to interpreting reductionist scientific models that finds reality hiding in places where it might not actually be." -- Provided by Publisher's Website