AtomzeitIndex

AtomzeitIndex is a proposed composite metric used to compare ensembles of atomic clocks and timekeeping services. It aims to provide a single-number summary of time and frequency stability across different platforms, including optical lattice clocks, fountain clocks, and cesium standards, as well as various environments and dissemination methods.

The index is not an official SI quantity. It is intended for research and benchmarking. AtomzeitIndex combines short-term frequency stability, long-term drift, environmental sensitivity, and reliability. The exact weighting is chosen by the evaluating body, allowing different evaluations for different contexts.

In a common formulation, sub-indices for short-term stability, expressed as S_y(τ); drift, D; environmental perturbations, E; and reliability, R, are normalized to a common scale and combined, for example as AtomzeitIndex = w1S_y_norm + w2D_norm + w3E_norm + w4(1-R_norm). Lower values indicate better performance. The specific weights and normalization schemes can vary between implementations.

Applications of the AtomzeitIndex include benchmarking laboratory clock networks, guiding development priorities for new clock technologies, and informing time-distribution studies. Limitations include dependence on the chosen weights, the diversity of clock types being compared, and the potential to obscure weaknesses in particular aspects of performance. As a non-standardized metric, the AtomzeitIndex is meant to complement established measures such as Allan deviation and Allan variance rather than replace them.

See also: atomic clock, timekeeping, Allan deviation, time scale, clock benchmarking.