The Challenge of Quantum Reality

1. The Challenge of Quantum Reality Darlene Fitzner

2. Black Box Demonstration • Different models can be created from one set of observable data. • Each model is equally acceptable if its predicts the observed results.

3. Background Knowledge:Young’s Double Slit Experiment

4. The Double Slit Experiment differs for Waves and Particles • For Particles... • For Waves...

5. Classical Particle Behaviour

6. Classical Wave Behaviour

7. Light Behaviour

8. Electron Behaviour

9. Wave-Particle Duality with Electrons Matter exhibits wave properties.

10. Particle Detector pg. 737 Pearson 4 3 2 1 0 1 2 3 4

11. Why the Wave only Model Fails Spooky action at a distance A water wave can be seen by all detectors. How does the water wave ‘know’ to only be seen at one detector?

12. Why the Particle only Model Fails S1 S2 How does a particle ‘know’ about slit 2? Something must go through both slits simultaneously.

13. Wave-Particle Duality and Light Evidence for photons.

14. Measurement Disturbance To measure which slit an electron goes through, we have to physically interact with it. Heisenberg’s Uncertainty Principle. Walter Lewin Dr. Quantum

15. Where Experimental Facts end and Interpretation begins... 1. Collapse Interpretation. • Electron leaves source as a particle. • Expands into a spread out wave as it passes through the slits. • Collapses back into a particle and arrives at only one of many possible places on the screen. Must accept that an electron physically changes from particle to wave and back again.

16. Where Experimental Facts end and Interpretation begins... 2. Pilot Wave Interpretation. • Electron always exists as a classical particle. • Electrons are guided by an invisible wave. The wave must be everywhere and know about everything in the universe, including what conditions will exist in the future. It knows if one or two slits are open AND if a detector is hiding behind the slits.

17. Where Experimental Facts end and Interpretation begins... 3. Many Worlds Interpretation. • Electron always exists as a classical particle. • When electrons demonstrate wave behaviour they exist in a superposition of many different states.. A parallel universe must exist for each of the electron’s possible states. Our universe must be constantly splitting into an almost infinite number of parallel universes, each having its own copy of every one of us.

18. Where Experimental Facts end and Interpretation begins... 4. Copenhagen Interpretation. • The mathematics only deals with the experimenter’s information about measurement interaction with the quantum mechanical system. What electrons are ‘doing’ or what they ‘are’ between the source and the screen is not possible to know. Must leave as unfounded questions.

19. Applications of Wave-Particle Duality • Electron Microscope • electron waves. • Electronics • electron waves. • Photons • particles of light. math.uwaterloo.ca

20. Plausible Future Explanations • Quantum Gravity • Loop Quantum Gravity vs. String Theory • Nonlocality

21. Awesome Resources • www.perimeterinstitute.ca • www.q2cfestival.com • Alice & Bob in Wonderland • Robert Spekkens • pirsa.org • Lucien Hardy The Quantum Tamers