Is Time Fundamental? Emergent Time in Quantum Systems.

Is Time Fundamental? Emergent Time in Quantum Systems.

Physics and Philosophy

2026

Rudolf Römer and Christoph Hoerl

The question of whether time is a fundamental feature of reality remains a central problem in attempts to unify quantum physics and general relativity, demanding an approach that brings physical theories into dialogue with philosophical questions about the nature of time and the fundamental structure of reality. The absence of an explicit time parameter in the Wheeler–DeWitt equation motivates relational approaches to time, such as the Page-Wootters mechanism explored computationally in this paper, where time emerges from the conditional probability of a system's state given the state of a clock subsystem. Here a Python simulation is used to approximate this, where one qubit acts as an internal clock and the remaining qubits constitute the physical system, and probabilistic projective measurements of the clock subsystem examine the formation of conditional system states and the emergence of temporal ordering. While constraints such as the simplified clock and finite system sizes limit what can be determined on the nature of time from these results, they illustrate how temporal descriptions may be reconstructed within a closed quantum system without assigning a fundamental role to an external time parameter, supporting the conceptual plausibility of emergent temporal structure.

Physics, philosophy, time, problem of time, quantum systems, quantum physics, emergent time