Eireversiibeli

Eireversiibeli is a term used in Finnish scholarly discourse to denote irreversibility of a process; literally "not reversible." It is applied to systems where the macroscopic evolution cannot be reversed to the initial configuration by any sequence of reversible dynamics alone; external input or dissipation is required.

In physics, eireversiibeli processes are those that generate entropy or dissipate energy, so that returning to the original state would require additional energy or information erasure beyond what reversible dynamics could provide. The concept is closely related to the thermodynamic arrow of time and to the distinction between reversible and irreversible evolution.

The term is used in discussions of thermodynamics, statistical mechanics, and, in some Finnish writings, irreversible computing or information processing, where it helps distinguish idealized reversible models from real-world processes that involve environment interaction.

Examples commonly cited include diffusion, heat conduction, frictional heating, plastic deformation, and the aging or wear of materials.

In Finnish literature, eireversiibeli is often contrasted with reversibility and with the broader notion of entropy-driven irreversibility; its precise usage can vary by author or discipline.