by Jim Baggott
23. For an excellent overview, see Matthew Saul Leifer, ‘Is the Quantum State Real? An Extended Overview of ψ–ontology Theorems’, Quanta, 3 (2014), 67–155.
Chapter 8: Quantum Mechanics is Incomplete So We Need to Add Some Other THINGS
1. See, for example, Guiseppe Pucci, Daniel M. Harris, Luiz M. Faria, and John W. M. Bush, ‘Walking Droplets Interacting with Single and Double Slits’, Journal of Fluid Mechanics, 835 (2018), 1136–56.
2. See Natalie Wolchover, ‘Famous Experiment Dooms Alternative to Quantum Weirdness’, Quanta Magazine, 11 October 2018: https://www.quantamagazine.org/famous-experiment-dooms-pilot-wave-alternative-to-quantum-weirdness-20181011/.
3. Peter R. Holland, The Quantum Theory of Motion: An Account of the de Broglie-Bohm Causal Interpretation of Quantum Mechanics (Cambridge University Press, Cambridge, UK, 1993), p. 475.
4. Ibid., p. 462.
5. Albert Einstein, letter to Max Born, 12 May 1952. Quoted in John S. Bell, Proceedings of the Symposium on Frontier Problems in High Energy Physics, Pisa, June 1976, pp. 33–45. This paper is reproduced in J. S. Bell, Speakable and Unspeakable in Quantum Mechanics: Collected Papers on Quantum Philosophy (Cambridge University Press, Cambridge, UK, 1987), pp. 81–92. The quote appears on p. 91.
6. See James T. Cushing, Quantum Mechanics: Historical Contingency and the Copenhagen Hegemony (University of Chicago Press, Chicago, 1994).
7. J. S. Bell, ‘On the Impossible Pilot Wave’, Foundations of Physics, 12 (1982), 989–99. This paper is reproduced in Bell, Speakable and Unspeakable in Quantum Mechanics, pp. 159–68.
8. J. S. Bell, ‘Against Measurement’, Physics World, 3 (1990), 33.
9. These estimates are taken from Roland Omnès, The Interpretation of Quantum Mechanics (Princeton University Press, Princeton, NJ, 1994). The original calculations were reported in E. Joos and H. D. Zeh, Zeitschrift für Physik, B59 (1985), 223–43.
10. For some examples, see Serge Haroche, ‘Entanglement, Decoherence and the Quantum/Classical Boundary’, Physics Today, July 1998, 36–42.
11. Frédéric Bouchard, Jérémie Harris, Harjaspreet Mand, Nicolas Bent, Enrico Santamato, Robert W. Boyd, and Ebrahim Karimi, ‘Observation of Quantum Recoherence of Photons by Spatial Propagation’, Nature Scientific Reports (2015), 5:15330.
12. Markus Arndt, Olaf Nairz, Julian Voss-Andreae, Claudia Keller, Gerbrand van der Zouw, and Anton Zeilinger, ‘Wave-particle Duality of C60 molecules’, Nature, 401 (1999), 680–2; Markus Arndt, Olaf Nairz, J. Petschinka, and Anton Zeilinger, ‘High Contrast Interference with C60 and C70’, Comptes Rendus de l’Académie des Sciences—Series IV—Physics, 2 (2001), 581–5; and Stefan Gerlich, Sandra Eibenberger, Mathias Tomandl, Stefan Nimmrichter, Klaus Hornberger, Paul J. Fagan, Jens Tüxen, Marcel Mayor, and Markus Arndt, ‘Quantum Interference of Large Organic Molecules’, Nature Communications (2011), 2:263. The analogies and puns are endless. The ratio of the diameter of a C60 molecule and the spacing of the silicon nitride grating used to observe the diffraction pattern is comparable to the ratio of the diameter of a conventional soccer ball and the width of a goal (according to FIFA standards), giving a potentially whole new meaning to the term ‘bend it like Beckham’.
13. See, for example, Jonathan R. Friedman, Vijay Patel, W. Chen, S. K. Tolpygo, and J. E. Lukens, ‘Quantum Superposition of Distinct Macroscopic States’, Nature, 406 (2000), 43–6, and Caspar H. van der Wal, A. C. J. ter Haar, F. K. Wilhelm, R. N. Schouten, C. J. P. M. Harmans, T. P. Orlando, Seth Lloyd, and J. E. Moonij, ‘Quantum Superposition of Macroscopic-Persistent States’, Science, 290 (2000), 773–7.
14.Bell, ‘Against Measurement’, 33.
15. Roger Penrose, The Large, the Small and the Human Mind, Canto edition (Cambridge University Press, Cambridge, UK, 2000), p. 82. Note that the collapse of the wavefunction is sometimes referred to as the ‘reduction’ of the wavefunction.
16. For example, in the second edition of David J. Griffiths’ popular textbook Introduction to Quantum Mechanics, published by Cambridge University Press in 2017, decoherence is mentioned just once, in a footnote.
17. See G. C. Ghirardi, A. Rimini, and T. Weber, ‘Unified Dynamics for Microscopic and Macroscopic Systems’, Physical Review D, 34 (1986), 470–91; and P. Pearle, ‘Combining Stochastic Dynamical State-Vector Reduction with Spontaneous Localization’, Physical Review A, 39 (1989), 2277–89. Although they’re not entirely equivalent, the ‘state vector’ referred to in the title of this paper can be taken to be similar to the wavefunction.
18. J. S. Bell, ‘Are There Quantum Jumps?’, in C. W. Kilmister (ed.), Schrödinger: Centenary Celebration of a Polymath (Cambridge University Press, Cambridge,UK, 1987), pp. 41–52. This article is reproduced in Bell, Speakable and Unspeakable in Quantum Mechanics, pp. 201–12. This quote appears on p. 204.
19. Giancarlo Ghirardi, ‘Collapse Theories’, Stanford Encylopedia of Philosophy, Substantive Revision, February 2016, p. 51.
20. John Wheeler, with Kenneth Ford, Geons, Black Holes and Quantum Foam: A Life in Physics (W.W. Norton, New York, 1998), p. 235.
21. L. Diósi, ‘A Universal Master Equation for the Gravitational Violation of Quantum Mechanics’, Physical Letters A, 120 (1987), 377–81; L. Diósi, ‘Models for Universal Reduction of Macroscopic Quantum Fluctuations’, Physical Review A, 40 (1989), 1165–74; and Roger Penrose, ‘On Gravity’s Role in Quantum State Reduction’, General Relativity and Gravitation, 28 (1996), 581–600.
22. Roger Penrose, The Emperor’s New Mind: Concerning Computers, Minds and the Laws of Physics (Vintage, London, 1990), p. 475.
23. See Jim Baggott, Quantum Space: Loop Quantum Gravity and the Search for the Structure of Space, Time, and the Universe (Oxford University Press, Oxford, 2018), pp. 259–62.
24. Roger Penrose, Fashion, Faith and Fantasy in the New Physics of the Universe (Princeton University Press, Princeton, NJ, 2016), p. 215.
25. Rainer Kaltenbaek, Gerald Hechenblaikner, Nikolai Kiesel, Oriol Romero-Isart, Keith C. Schwab, Ulrich Johann, and Markus Aspelmeyer, ‘Macroscopic Quantum Resonators (MAQRO)’, Experimental Astronomy, 34 (2012), 123–64, see also arXiv:quant-ph/1201.4756v2, 19 March 2012.
26. Rainer Kaltenbaek, et al., ‘Macroscopic Quantum Resonators (MAQRO): 2015 Update’, EPJ Quantum Technology, 3 (2016), 5.
Chapter 9: Quantum Mechanics is Incomplete Because We Need to Include My Mind (Or Should That Be Your Mind?)
1. John von Neumann, Mathematical Foundations of Quantum Mechanics (Princeton University Press, Princeton, NJ, 1955), p. 420.
2. Ibid., p. 421.
3. L. Szilard, ‘On Entropy Reduction in a Thermodynamic System by Interference by Intelligent Beings’, Zeitschrift fur Physik, 53 (1929), 840–56. NASA Technical Translation F-16723.
4. Max Jammer, The Philosophy of Quantum Mechanics (Wiley, New York, 1974), p. 480. The italics are mine.
5. Eugene Wigner was another Hungarian compatriot. Together with Szilard and Edward Teller, Wigner was part of the ‘Hungarian conspiracy’ that influenced Einstein to write a letter to US President Franklin D. Roosevelt on 2 August 1939 warning of ‘extremely powerful bombs of a new type’. See Jim Baggott, Atomic: The First War of Physics and the Secret History of the Atom Bomb 1939–49 (Icon Books, London, 2009), pp. 18–19.
6. Eugene Wigner, ‘Remarks on the Mind-Body Question’, in I. J. Good (ed.), The Scientist Speculates: An Anthology of Partly-Baked Ideas (Heinemann, London, 1961), pp. 284–302. This is reproduced in John Archibald Wheeler and Wojciech Hubert Zurek (eds), Quantum Theory and Measurement (Princeton University Press, Princeton, NJ, 1983), pp. 168–81. These quotes appear on pp. 176–8.
7. John Archibald Wheeler, ‘Law without Law’, in Wheeler and Zurek (eds), Quantum Theory and Measurement, pp. 182–213. This quote appears on p. 184.
8. Ibid., p. 185.
9. John Archibald Wheeler, ‘Genesis and Observership’, in Robert E. Butts and Jaakko Hintikka (eds), Foundational Problems in the Special Sciences (D. Reidel, Dordrech
t, Holland, 1977), p. 28. Wheeler was referring to Robert Dicke, who highlighted the ‘fine tuning’ in physical laws and constants that seems to be necessary in order for life to be possible in the Universe, and Brandon Carter, who developed the anthropic principle in 1974 as a direct challenge to the Copernican principle.
10. John Wheeler, with Kenneth Ford, Geons, Black Holes and Quantum Foam: A Life in Physics (W.W. Norton, New York, 1998), p. 338.
11. John D. Barrow and Frank Tipler, The Anthropic Cosmological Principle (Oxford University Press, Oxford, 1986), p. 22. Italics in the original.
12. David J. Chalmers, ‘Facing up to the problem of consciousness’, Journal of Consciousness Studies, 2 (1995), 200–19.
13. Neuroscientists Stephen Macknik and Susana Martinez-Conde explore the neuroscience of magic in their entertaining book Sleights of Mind, published by Profile Books, London, 2011.
14. Gilbert Ryle, The Concept of Mind (Hutchinson, London, 1949).
15. Daniel Dennett, Consciousness Explained (Penguin, London, 1991).
16. Not all neuroscientists agree. For a lucid and witty rebuttal of the reductionist approach, I recommend Raymond Tallis, Aping Mankind: Neuromania, Darwinitis, and the Misrepresentation of Humanity (Routledge Classics, London, 2016). For alternative ‘top-down’ arguments, see George Ellis, How Can Physics Underlie the Mind: Top-Down Causation in the Human Context (Springer-Verlag, Berlin, 2016).
17. Cambridge Declaration on Consciousness, 7 July 2012.
18. Roger Penrose, The Emperor’s New Mind: Concerning Computers, Minds, and the Laws of Physics (Vintage, London, 1990), p. 540.
19. Ibid., p. 517.
20. Recent computer simulations of the molecular dynamics of a guanosine diphosphate (GDP) bound tubulin made use of a structure consisting of 13,432 atoms, not counting the 150,510 water molecules which surrounds and ‘solvates’ it. See Yeshitila Gebremichael, Jhih-Wei Chu, and Gregory A. Voth, ‘Intrinsic Bending and Structural Rearrangement of Tubulin Dimer: Molecular Dynamics Simulations and Coarse-Grained Analysis’, Biophysical Journal, 95 (2008), 2487–99.
21. Max Tegmark, ‘The Importance of Quantum Decoherence in Brain Processes’, Physical Review E, 61 (2000), 4194–206. See also arXiv:quant-ph/9907009v2, 10 November 1999.
22. Satyajit Sahu, Subrata Ghosh, Kazuto Hirata, Daisuke Fujita, and Anirban Bandyopadhyay, ‘Multi-level Memory-Switching Properties of a Single Brain Microtubule’, Applied Physics Letters, 102 (2013), 123701.
23. Stuart Hameroff and Roger Penrose, ‘Consciousness in the Universe: A Review of the “Orch-OR” Theory’, Physics of Life Reviews, 11 (2014), 70.
24. Chalmers, ‘Facing up to the problem of consciousness’, pp. 200–19. The italics are mine.
Chapter 10: Quantum Mechanics is Incomplete Because…. Okay, I Give Up
1. Albert Einstein, ‘Approximative Integration of the Field Equations of Gravitation’, Preussische Akademie der Wissenschaften (Berlin) Sitzungsberichte, 1916, 688–96. Quoted in Gennady E. Gorelik and Viktor Ya. Frenkel, Matvei Petrovich Bronstein and Soviet Theoretical Physics in the Thirties (Birkhäuser Verlag, Basel, 1994). The quote appears on p. 86.
2. Hugh Everett III, ‘ “Relative State” Formulation of Quantum Mechanics’, Reviews of Modern Physics, 29 (1957), 454–62. This is reproduced in John Archibald Wheeler and Wojciech Hubert Zurek (eds), Quantum Theory and Measurement (Princeton University Press, Princeton, NJ), 1983, pp. 315–23. This quote appears on p. 316. Italics in the original. I should point out that Everett left academia and joined the Pentagon’s Weapons System Evaluation Group in June 1956, and although this paper doesn’t carry Wheeler’s name it represents a compromise that Everett was never entirely happy with.
3. Hugh Everett III, ‘The Theory of the Universal Wave Function’, Princeton University PhD Thesis. This is reproduced in B. S. DeWitt and N. Graham (eds), The Many Worlds Interpretation of Quantum Mechanics (Pergamon Press, Oxford, 1975). The italics are mine.
4. Everett, ‘The Theory of the Universal Wave Function’, footnote on p. 68. Italics in the original.
5. Stefano Osnaghi, Fábio Freitas, and Olival Freire Jr, ‘The Origin of the Everettian Heresy’, Studies in the History and Philosophy of Modern Physics, 40 (2009), 111.
6. Everett, ‘The Theory of the Universal Wave Function’, p. 9.
7. Nancy G. Everett, letter to Frank J. Tipler, 10 October 1983. Quoted by Eugene Shikhovtsev, ‘Biographical Sketch of Hugh Everett, III’, available in an online version maintained by Max Tegmark: http://space.mit.edu/home/tegmark/everett/everett.html
8. Bryce S. DeWitt, ‘Quantum Mechanics and Reality’, Physics Today, 23 (1970), 30. This is reproduced in DeWitt and Graham (eds), The Many Worlds Interpretation of Quantum Mechanics.
9. John Wheeler, in P. C. W. Davies and J. R. Brown (eds), The Ghost in the Atom: A Discussion of the Mysteries of Quantum Physics (Cambridge University Press, Cambridge, UK, 1986), p. 60.
10. J. A. Wheeler, letter to Paul Benioff, 7 July 1977. Quoted by Shikhovtsev, ‘Biographical Sketch of Hugh Everett, III’.
11. DeWitt, ‘Quantum Mechanics and Reality’, p. 33.
12. This is an observation frequently attributed to John Wheeler, but I picked it up from the interview with David Deutsch which appears in Davies and Brown, The Ghost in the Atom, p. 84.
13. H. D. Zeh, ‘The Problem of Conscious Observation in Quantum Mechanical Description’, Foundations of Physics Letters, 13 (2000), 221–33. See also arXiv:quant-ph/9908084v3, 5 June 2000. Zeh explains that this paper is an update of a paper that was first informally circulated through the Epistemological Letters of the Ferdinand-Gonseth Association in Biel, Switzerland, in 1981.
14. Michael Lockwood, Mind, Brain and the Quantum. The Compound ‘I’ (Blackwell, Oxford, 1990).
15. David Z. Albert, Quantum Mechanics and Experience (Harvard University Press, Cambridge, MA, 1992).
16. J. S. Bell, ‘Quantum Mechanics for Cosmologists’, in C. Isham, R. Penrose, and D. Sciama (eds), Quantum Gravity 2 (Clarendon Press, Oxford, 1981). This paper is reproduced in J. S. Bell, Speakable and Unspeakable in Quantum Mechanics (Cambridge University Press, Cambridge, UK, 1987), pp. 117–38. This quote appears on p. 118.
17. Murray Gell-Mann, The Quark and the Jaguar: Adventures in the Simple and the Complex (Little, Brown, London, 1994), p. 138.
18. Adrian Kent, ‘One World versus Many: The Inadequacy of Everettian Accounts of Evolution, Probability, and Scientific Confirmation’, in Simon Saunders, Jonathan Barrett, Adrian Kent, and David Wallace (eds), Many Worlds? Everett, Quantum Theory, & Reality (Oxford University Press, Oxford, 2010), p. 310.
19. David Deutsch, The Fabric of Reality (Allen Lane, London, 1997), p. 45.
20. Ibid., p. 53.
21. Ibid., p. 216.
22. Max Tegmark, ‘The Interpretation of Quantum Mechanics: Many Worlds or Many Words?’, Fortschritte der Physik, 46 (1998), 855–62. See also arXiv:quant-ph/9709032v1, 15 September 1997. This quote appears on p. 5.
23. David Wallace, The Emergent Multiverse: Quantum Theory According to the Everett Interpretation (Oxford University Press, Oxford, 2012), p. 158.
24. Ibid., p. 371.
25. Lev Vaidman, ‘Review: David Wallace, The Emergent Multiverse’, British Journal for the Philosophy of Science, 66 (2014), 465–8. See also Lev Vaidman, ‘Many-Worlds Interpretation of Quantum Mechanics’, Stanford Encyclopedia of Philosophy, substantive revision 17 January 2014.
26. David Wallace, ‘Decoherence and Ontology (or: How I Learned to Stop Worrying and Love FAPP)’, in Simon Saunders, Jonathan Barrett, Adrian Kent, and David Wallace (eds), Many Worlds? Everett, Quantum Theory, & Reality (Oxford University Press, Oxford, 2010), p. 62.
27. R. Raussendorf and H. J. Briegel, ‘A One-Way Quantum Computer’, Physics Review Letters, 86 (2001), 5188–91.
28. P. Walther, K. J. Resch, T. Rudolph, E. Schenck, H. Weinfurter, V. Vedral, M. Aspelmeyer, and A. Zeilinger, ‘Experimental One-Way Quantum Computing’, Nature, 434 (2005), 1
69–76. See also arXiv:quant-ph/0503126, 14 March 2005.
29. Michael Cuffaro, ‘Many Worlds, the Cluster State Quantum Computer, and the Problem of the Preferred Basis’, Studies in History and Philosophy of Modern Physics, 43 (2012), 35–42. See also arXiv:physics.hist-ph/1110.2514v2, 10 January 2012. This quote appears on p. 17.
30. Michael Cuffaro, personal communication, 19 June 2019.
31. David Wallace, personal communication, 25 June 2019.
32. David Wallace, personal communication, 27 June 2019.
33. David Deutsch, interview with John Horgan, ‘The Infinite Optimism of Physicist David Deutsch’, 17 January 2018, https://blogs.scientificamerican.com/cross-check/the-infinite-optimism-of-physicist-david-deutsch/
34. Martin Rees, ‘What are the Limits of Human Understanding?’, Prospect Magazine, 13 November 2018. https://www.prospectmagazine.co.uk/magazine/martin-rees-what-are-the-limits-of-human-understanding
35. Max Tegmark, Our Mathematical Universe: My Quest for the Ultimate Nature of Reality (Penguin Books, London, 2015); see particularly Chapter 8.
36. See for example Jim Baggott, Farewell to Reality: How Fairy-tale Physics Betrays the Search for Scientific Truth (Constable, London, 2013), especially Chapter 9; and Sabine Hossenfelder, Lost in Math: How Beauty Leads Physics Astray (Basic Books, New York, 2018).
37. See Christopher A. Fuchs, ‘Copenhagen Interpretation Delenda Est?’, arXiv:quant-ph/1809.05147v2, 11 November 2018.
38. Adam Becker, What is Real? The Unfinished Quest for the Meaning of Quantum Physics (John Murray, London, 2018), p. 264.
39. Lee Smolin, Einstein’s Unfinished Revolution: The Search for What Lies beyond the Quantum (Allen Lane, London, 2019), p. xxiii.
40. Helge Kragh, Higher Speculations: Grand Theories and Failed Revolutions in Physics and Cosmology (Oxford University Press, Oxford, 2011), p. 285. The italics are mine.
41. Albert Einstein, ‘On the Generalized Theory of Gravitation’, Scientific American, 182 (April 1950), p. 13. Einstein continues: ‘I believe that every true theorist is a kind of tamed metaphysicist, no matter how pure a “positivist” he may fancy himself. The metaphysicist believes that the logically simple is also the real. The tamed metaphysicist believes that not all that is logically simple is embodied in experienced reality, but that the totality of all sensory experience can be “comprehended” on the basis of a conceptual system built on premises of great simplicity.’