I read a paper on how spacetime on the level of special relativity can be built from "magma." This is not hot molten rock in the Earth, but a groupoid construction. This was a while ago, almost 10 years, but I read it well; I had to for I was a referee on it. I can't find it right now, but I will try to search it out.
LC On Sunday, May 10, 2020 at 6:45:35 AM UTC-5, Philip Thrift wrote: > > > > > cf. > https://www.researchgate.net/publication/325907723_A_gentle_introduction_to_Schwinger's_formulation_of_quantum_mechanics_The_groupoid_picture > > > > > *Schwinger’s picture of Quantum Mechanics* > https://arxiv.org/pdf/2002.09326.pdf > > > *In this paper we will present the main features of what can be called > Schwinger's foundational approach to Quantum Mechanics. The basic > ingredients of this formulation are the selective measurements, whose > algebraic composition rules define a mathematical structure called > groupoid, which is associated with any physical system. After the > introduction of the basic axioms of a groupoid, the concepts of observables > and states, statistical interpretation and evolution are derived. An > example is finally introduced to support the theoretical description of > this approach.* > > Finally, we will introduce *a quantum measure* associated with the state > ρ > > First, we realize that the state ρ on C∗(G) defines a decoherence > functional D on the σ-algebra Σ of events of the groupoid G > > We define a quantum measure µ on Σ > > ... > > > > @philipthrift > Click > > > > @philipthrift > -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/a614805b-542f-4211-b0c3-7f8835ead167%40googlegroups.com.
