Fredkinpoorten

Fredkinpoorten is the Dutch term for Fredkin gates, a class of reversible logic gates named after Edward Fredkin. A Fredkin gate is a three-input, three-output device that implements a controlled swap: with inputs (C, A, B), the outputs are (C, A', B'), where if C is 1 the two data lines A and B are swapped, and if C is 0 they remain unchanged. In all cases the outputs are a permutation of the inputs, making the gate bijective and hence reversible.

The gate is conservative, preserving the number of ones among the outputs relative to the inputs (the Hamming weight). This reversibility means no information is lost during operation, a property that aligns with aims in low-power computing and physical implementations where energy dissipation is minimized. The Fredkin gate can be described as a controlled-swap operation and forms a fundamental building block in reversible logic.

In terms of computation, the Fredkin gate is universal for reversible computation, meaning that any reversible computation can be implemented using networks of Fredkin gates (often with ancillary inputs). Because reversible gates are foundational in quantum circuits, the Fredkin gate also plays a role in quantum information processing as a unitary, quantum-compatible operation known as the controlled-SWAP gate.

In Dutch-language literature, Fredkinpoorten are discussed as the practical realization of the Fredkin gate concept, including its properties, decompositions into simpler components, and its use in modeling energy-efficient and quantum-friendly computation.