Unifying gravity and quantum theory requires better understanding of time

Ricardo Muciño

The work leading to this thesis focuses on assessing and extending quantum theories in order to explore and test their implications across various regimes -- including thermodynamics, semiclassical and quantum gravity scenarios, and the in principle detectable predictions of such theories. The general motivation stems from a basic desire to understand the world form its very foundations. For instance, how can we bridge the gap between what we observe or `perceive' and the fundamental quantum nature in our theories. In particular, this work originated from the search to a better understanding of the nature of time according to our physical theories and the common perception that it invariably `flows' to the future, or, in other words, why do we observe distinct natural processes evolving asymmetrically in time? These motivations led to three distinct, yet interconnected and successful, lines of research, presented here in three separate parts: I. On Possible Detections within Physical Theories; II. On Explaining the Approach to Thermodynamic Equilibrium; and III. Relativistic Collapse Theories and a Self-Consistent Model of Semiclassical Gravity.

William George Unruh

Ryusho Nemoto

This preprint introduces a new probabilistic framework for quantum theory by applying stochastic geometry to the interpretation of quantum state transitions. It redefines time as a series of probabilistically generated "tensions"—discrete time units—that govern the evolution of quantum states. This approach allows for the discretization of the Schrödinger equation and provides a new foundation for understanding quantum uncertainty, time, and the structure of spacetime, contributing to the broader pursuit of a quantum gravity theory and Grand Unified Theory.

Carl Friedrich von Weizsäcker, Thomas Görnitz, Holger Lyre

Claus Kiefer

Duchesne, Jonathan

Contact Jonathan.duchesne@hotmail.com 418-953-0596 This thesis presents Time–Decoherence Gravity (TDG), a unified theoretical framework in which spacetime geometry, gravitation, and the physical flow of time arise from fundamental quantum decoherence. Rather than treating decoherence as an environmental or effective process, TDG builds on a covariant extension of the Gorini–Kossakowski–Sudarshan–Lindblad (GKSL) equation, where four directional Lindblad operators encode intrinsic, irreversible information loss. These operators define a “decoherence tensor,” which acts both as a memory of quantum irreversibility and as the generator of emergent spacetime geometry through a nonlinear constitutive relation. The theory provides a coherent gravitational collapse mechanism based on the incompatibility of decoherence patterns across quantum branches. This leads to an intrinsic “decoherence energy,” whose magnitude determines the collapse timescale, extending and generalizing the well-known Penrose–Diósi models. TDG predicts a smooth transition from persistent microscopic coherence to rapid macroscopic collapse. At cosmological scales, a homogeneous decoherence tensor naturally generates modified Friedmann dynamics, early-universe stiff-fluid behavior, and late-time acceleration without requiring a fine-tuned cosmological constant. Black-hole entropy emerges as a saturation of decoherence memory at the horizon, while Hawking radiation appears as the dissipative relaxation of this saturation. The theory also predicts short-range deviations from Newtonian gravity and a universal spectrum of fundamental gravitational noise. Finally, TDG offers several experimentally testable signatures involving optical clocks, mesoscopic interferometry, short-range force measurements, and correlated phase noise in global timing networks. The framework is internally consistent, falsifiable, and provides a novel and unified approach to the relationship between quantum mechanics, gravity, and the arrow of time.