Translations:Coherence - book/7/en

What, then, is coherence? Coherence (or coherency) is a basic word having many related meanings. The word cohere means “to stick or hold together” and refers to things that are connected logically in a united or orderly whole. Coherence is the quality or the state of a logical or orderly relationship among parts. In physics, coherence can refer to waves with a continuous relationship among phases. Coherence is characterized by a fixed phase relationship among points on a wave. A truly monochromatic wave would be perfectly coherent at all points in space. In practice, however, the region of high coherence of a seismic wave generally extends only over a finite interval.