CHAPTER FOUR. Quantum Theory and Spacetime

W. M. Stuckey, Michael Silberstein, Timothy J. McDevitt

Abstract Chapter 1 points out that the mystery of entanglement has led Physics Nobel Laureates to claim “nobody understands quantum mechanics.” The Chapter goes on to introduce: the EPR and EPR–Bell paradoxes, various attempts to resolve them, our proposed resolution whereby the relativity principle (no preferred reference frame, NPRF) justifies the Planck postulate (NPRF + h) exactly like the relativity principle justifies the light postulate (NPRF + c), the Planck postulate as a result of Information Invariance & Continuity from quantum information theory, the importance of the relativity principle, subjective versus objective spacetime models of reality, spacelike and timelike relations in spacetime, and four experiments leading to our Poincaré symmetric ontology.

Carl Friedrich von Weizsäcker, Thomas Görnitz, Holger Lyre

George Jaroszkiewicz

This chapter focuses on the fact that by definition, empty spacetime cannot be observed. Therefore, there is room here not only for different mathematical models of the information void (the spacetime region devoid of any detection apparatus) but also for different interpretations as to what space and time actually mean there. The chapter discusses Mach’s relationalism and Einstein’s view of the aether. It discusses Planck’s quantization hypothesis, photons, and the possibility of modelling the information void with something other than Minkowski spacetime. The chapter finishes with a discussion of Hartland Snyder’s quantized spacetime algebra, a modification of standard relativistic quantum theory that may yet provide a better model for the void than classical Minkowski spacetime. The chapter shows that in Snyder’s model, space is quantized but time is not.

Wolfram Schommers

Christian Wüthrich, Nick Huggett

This is a chapter of the planned monograph "Out of Nowhere: The Emergence of Spacetime in Quantum Theories of Gravity", co-authored by Nick Huggett and Christian Wüthrich and under contract with Oxford University Press. (More information at www.beyondspacetime.net.) This chapter sketches how spacetime emerges in causal set theory and demonstrates how this question is deeply entangled with genuinely philosophical concerns.