Fundamental Irreversibility: Planckian or Schr\"odinger-Newton?

Abstract

The inception of a universal gravity-related irreversibility took place originally in quantum cosmology. The ultimate reason of universal irreversibility is thought to come from black holes close to the Planck scale. Completely different instances of irreversibilities are quantum state reductions unrelated to gravity or relativity but related to measurement devices. However, an intricate relationship between Newton gravity and quantized matter might result in fundamental and spontaneous quantum state reduction --- in the non-relativistic Schr\"odinger-Newton context. The above two concepts of fundamental irreversibility emerged and evolved with few or even no interactions. The purpose here is to draw a parallel between the two approaches first, and to ask rather than answer the question: can both the Planckian and the Schr\"odinger-Newton indeterminacies/irreversibilities be two faces of the same universe. A related personal note of the author's 1986 meeting with Aharonov and Bohm is appended.