Build an intuitive understanding of the principles behind quantum mechanics through practical construction and replication of original experiments With easy-to-acquire, low-cost materials and basic knowledge of algebra and trigonometry, Exploring Quantum Physics through Hands-on Projects takes readers step by step through the process of re-creating scientific experiments that played an essential role in the creation and development of quantum mechanics.
Presented in near chronological order—from discoveries of the early twentieth century to new material on entanglement—this book includes question- and experiment-filled chapters on:
- Light as a Wave
- Light as Particles
- Atoms and Radioactivity
- The Principle of Quantum Physics
- Wave/Particle Duality
- The Uncertainty Principle
- Schrödinger (and his Zombie Cat)
- Entanglement
From simple measurements of Planck's constant to testing violations of Bell's inequalities using entangled photons, Exploring Quantum Physics through Hands-on Projects not only immerses readers in the process of quantum mechanics, it provides insight into the history of the field—how the theories and discoveries apply to our world not only today, but also tomorrow.
By immersing readers in groundbreaking experiments that can be performed at home, school, or in the lab, this first-ever, hands-on book successfully demystifies the world of quantum physics for all who seek to explore it—from science enthusiasts and undergrad physics students to practicing physicists and engineers.
Table of Contents:
Introduction xi Prologue xv
Important Disclaimer and Warnings xix
Acknowledgments xxiii
About the Authors xxv
1 LIGHT AS AWAVE 1
Newton’s View: Light Consists of Particles 1
Young’s Interference of Light 3
Automatic Scanning of Interference Patterns 6
The Final Nail in the Coffin for Newton’s Theory of Light 8
Light as an Electromagnetic Wave 9
Polarization 11
Optics with 3-cm Wavelength “Light” 11
Real-World Behaviors 16
Double-Slit Interference with Microwaves 17
The Doppler Effect 18
Experiments and Questions 20
2 LIGHT AS PARTICLES 23
The Seed of Quantum Physics: Planck’s Formula 27
The Photoelectric Effect 28
Can we Detect Individual Photons? 36
Low-Cost PMT Power Supplies 38
Listening to Individual Photons 41
Where does this Leave Us? 45
Experiments and Questions 45
3 ATOMS AND RADIOACTIVITY 49
The Need for Vacuum 49
The Mechanical Vacuum Pump 51
The Vacuum Gauge 53
A Very-High-Voltage Power Supply 56
A Vacuum Tube Legow Set 56
Phosphor Screens 59
The Electron Gun 60
The Discovery of the Electron 61
Cathode-Ray Tubes 63
Thomson’s First 1897 Experiment—Negative Charge and Rays are Joined Together 65
Thomson’s Second Experiment—Electrostatic Deflection of Cathode Rays 67
Thomson and the Modern CRT 69
Thomson’s Third Experiment—Mass-to-Charge Ratio of the Electron 72
Measuring e/m with our CRT 74
A Magical Measurement of e/m 77
Thomson’s “Plum Pudding” Model of the Atom 79
Geiger–Mu¨ller Counter 80
a, b, and g 89
The Nature of Beta Radiation 92
The Ionizing Power of Alpha 92
What are Alpha Particles? 95
Rutherford’s Alpha-Scattering Experiment 96
Rutherford’s Planetary Model of the Atom 102
Experiments and Questions 103
4 THE PRINCIPLE OF QUANTUM PHYSICS 107
Emission Spectroscopy 107
Bohr’s Spark of Genius 113
Orbitals and Not Orbits 115
Quantization—The Core of Quantum Physics 117
Experiments and Questions 118
5 WAVE–PARTICLE DUALITY 121
Gamma-Ray Spectrum Analysis 122
What is the Nature of Light? 126
Two-Slit Interference with Single Photons 128
Imaging Single Photons 133
The Answer: Complementarity 135
Matter Waves 137
Matter Waves and the Bohr Atom 137
Experimental Confirmation of De Broglie’s Matter Waves 138
Two-Slit Interference with Single Electrons 142
A Simple TEM 144
Blurring the Line Between Quantum and Classical 148
Particle–Wave Duality in the Macroscopic World 148
Experiments and Questions 149
6 THE UNCERTAINTY PRINCIPLE 151
Wavefunctions 151
The Uncertainty Principle 153
Experimental Demonstration of the Uncertainty Principle 155
Time–Energy Uncertainty 159
Fourier Analysis 159
Bye, Bye Clockwork Universe 163
Experiments and Questions 165
7 SCHRO¨ DINGER (AND HIS ZOMBIE CAT) 167
Real-World Particle in a Box 171
Quantum Tunneling 174
Quantum Tunneling Time 178
Many-Worlds Interpretation 183
Schro¨dinger’s Cat in the Lab 184
Beam Splitters 186
Who Rolls the Dice? 190
The Mach–Zehnder Interferometer 192
“Which-Way” Experiments 197
The Quantum Eraser 199
Experiments and Questions 200
8 ENTANGLEMENT 203
Bell’s Inequalities 205
An Entangled-Photon Source 211
Detecting Entangled Photons 214
High-Purity Single-Photon Source 219
Testing Bell’s Inequality 220
Closing the Loopholes 225
The Age of Quantum Information 226
A Quantum Random-Number Generator 228
Quantum Information 229
Quantum Teleportation 230
Faster-Than-Light Communication 236
Quantum Cryptography 237
Quantum Computing and Technologies for the Future 240
Experiments and Questions 242
REFERENCES 245
SOURCES FOR MATERIALS AND COMPONENTS 249
ABBREVIATIONS 255
INDEX 257
