Quantum Mechanics at the Crossroads (eBook)

James Evans is a historian of science and professor of physics at the University of Puget Sound. He is the author of The History and Practice of Ancient Astronomy, as well of numerous articles on the history of physics. His scientific papers include studies of optical-mechanical analogies in the context of general relativity. Alan Thorndike is a professor of physics at the University of Puget Sound. His first field of research involved the behavior of sea ice in the Arctic Ocean, but he is now engaged with experimental quantum optics.

Preface 6
Contents 8
List of Contributors 10
1 Introduction: Contexts and Challenges for Quantum Mechanics 12
1.1 Periodization of Quantum Mechanics 13
1.2 Determinism, Entanglement, Locality, and the Quantum – Classical Divide 18
1.3 Quantum Mechanics in the Baroque Age 25
References 29
2 Max Planck’s compromises on the way to and from the Absolute 32
2.1 Scientific 32
2.2 Personal 42
References 46
3 Atomic Waves in Private Practice 49
3.1 Family Life 51
3.2 The Modern World 53
3.3 Sibling Partnership 55
3.4 Benefits of War 57
3.5 Industry 60
3.6 Physique Redux 61
3.7 X-Ray Photoeffect 62
3.8 Relativistic Revelation 65
3.9 Matter Waves 66
3.10 Sinuous Legacy 68
Acknowledgements 71
References 71
4 A Complementary Opposition: Louis de Broglie and Werner Heisenberg 82
References 88
5 Schrödinger Against Particles and Quantum Jumps 90
Introduction 90
5.1 Dispensing with Particles 91
5.2 Getting Rid of Quantum Jumps 103
Conclusion 110
References 111
6 Aspects of Nonlocality in Quantum Mechanics 116
6.1 Introduction 116
6.2 The Superposition Principle and Entangled States 116
6.3 Einstein–Podolsky–Rosen (EPR) 118
6.4 A Generalized Version of Bell’s Theorem 120
6.5 Experimental Tests of Bell’s Inequality 124
6.6 What Kind of Nonlocality is Implied by a Violation of Bell’s Inequality? 126
6.7 The Need for a Deeper Physics 128
References 130
7 Decoherence and the Foundations of Quantum Mechanics 133
7.1 Introduction 133
7.2 Basics of Decoherence 134
7.3 Decoherence and the Measurement Problem 137
7.4 Resolution into Subsystems and the Closed-Universe Objection 143
7.5 Decoherence and Interpretations of Quantum Mechanics 144
7.6 Outlook 151
References 152
8 What Are Consistent Histories? 157
8.1 Introduction 157
8.2 How Does a System Get from a to b? 158
8.3 Testing for Consistent Histories 162
8.4 Conclusion 164
References 165
9 Bose–Einstein Condensation: Identity Crisis for Indistinguishable Particles 166
9.1 The Phenomenon of Bose–Einstein Condensation 166
9.2 How to Count Classical and Quantum Particles 168
9.3 Bose–Einstein Statistics and Planck’s Black-Body Spectrum 172
9.4 Why Photons Don’t Condense 172
9.5 Bose–Einstein Condensation and Entropy 174
9.6 Absolute Indistinguishability 174
9.7 Some Historical Remarks 175
9.8 What are the Conditions for Observing Bose – Einstein Condensation? 177
9.9 How to Cool to Bose–Einstein Condensation 179
9.10 Observation of Bose –Einstein Condensation 181
9.11 A Bose–Einstein Condensate Has a Macroscopic Wavefunction 182
9.12 Atom Lasers and Atom Amplification 185
9.13 Outlook 187
Acknowledgments 188
References 189
10 Quantum Fluctuations of Light: A Modern Perspective on Wave/ Particle Duality 190
10.1 Introduction 190
10.2 A Criterion for Nonclassicality 194
10.3 Light Sources and Their Fluctuations 196
10.4 Photon Antibunching: A Probe of Particle Fluctuations 199
10.5 Quadrature Squeezing: A Probe of Wave Fluctuations 202
10.6 Wave –Particle Correlations 206
10.7 A Concluding Comment 211
References 215
11 Quantum Entanglement as a Resource for Communication 220
11.1 What is Entanglement? 220
11.2 Entanglement in Communication 225
11.3 A Teleportation Experiment 233
11.4 Conclusion 236
References 236
12 The Three Cases of Doctor von Neumann 238
12.1 Setting the Stage 238
12.2 Von Neumann’s Three Enigmas 239
12.3 Three Lines of Investigation 241
12.4 The Last Chapter 246
References 247
About the Authors 249
Index 251