So, the relative phases of these two light fields are still changed in an unpredictable way.

If the points of interest are widely separated in space, it is difficult to measure the relative phase.

In the second picture, it is a question of the relative phase of the component frequencies.

States in different superselection sectors cannot influence each other, and the relative phases between them are unobservable.

This definition assumes that the basis set of states has been picked so that there is no information on their relative phases.

Two waves are said to be coherent if they have a constant relative phase.

The process by which the relative phases of precision clocks are compared for the purpose of defining a single time standard.

If two processes of identical period are occurring simultaneously, they may be compared with respect to their relative phase.

Directivity depends on relative phases of signal radiated from different elements.

This constructive or destructive interference happens due to the relative phases of the waves from each driver as they reach the listening position.