chronon

Chronon is a term used in physics to denote a hypothetical quantum of time, an indivisible unit that would structure temporal evolution in discrete steps rather than a continuous flow. In various discrete-time theories, a chronon tau serves as the fundamental time interval over which dynamical changes occur. There is no single agreed definition or value for the chronon, and the concept remains speculative; mainstream physics models time as a continuous parameter, and experimental evidence for time quantization is lacking.

One notable instantiation is Caldirola’s chronon model of the electron, which assigns a finite intrinsic time interval to the emission of radiation and replaces certain aspects of classical electrodynamics with a discrete-time framework. This approach aims to address issues such as pre-acceleration and runaway solutions, but it is not universally accepted and remains a theoretical proposal. Beyond this, chronon-like time stepping appears in some discrete-time formulations of quantum mechanics and in lattice-field theories used for computational or conceptual explorations of time quantization.

Relation to Planck time and experimentation: while Planck time is often cited as a natural unit for fundamental physics, the chronon is not tied to a universally recognized scale. To date, no experiment has confirmed time quantization, and any such discreteness would manifest at scales that are extraordinarily small or in regimes not yet accessible.

See also Planck time; time quantization; discrete time; Caldirola chronon.