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General Relativistic Hydrodynamics in Discrete Spacetime: Perfect Fluid Accretion onto Static and Spinning Black Holes
Jonathan Gorard
This study investigates the effect of spacetime discretization on accretion dynamics of a relativistic fluid onto a spinning black hole, specifically noting that accretion rates decrease with increased discretization scale and that drag force sensitivity and instabilities intensify at critical discretization values.
Hypergraph Discretization of the Cauchy Problem in General Relativity via Wolfram Model Evolution
Jonathan Gorard
This article introduces a numerical general relativity code using the Z4 formulation with hypergraph-based Cauchy data and adaptive mesh refinement, validating results against standard spacetimes and comparing with Wolfram model evolution.
Faster than Light in Our Model of Physics: Some Preliminary Thoughts
Stephen Wolfram
“So you think you have a fundamental theory of physics. Well, then tell us if warp drive is possible!” Despite the hopes and assumptions of science fiction, real physics has for at least a century almost universally assumed that no genuine effect can ever propagate through physical space any faster than light. But is this actually true? We’re now in a position to analyze this in the context of our model for fundamental physics. And I’ll say at the outset that it’s a subtle and complicated question, and I don’t know the full answer yet.
Event Horizons, Singularities and Other Exotic Spacetime Phenomena
Stephen Wolfram
In our models, space emerges as the large-scale limit of our spatial hypergraph, while spacetime effectively emerges as the large-scale limit of the causal graph that represents causal relationships between updating events in the spatial hypergraph. An important result is that (subject to various assumptions) there is a continuum limit in which the emergent spacetime follows Einstein’s equations from general relativity.