Definition of spatial and temporal coherence in QM?
Answers
a) temporal coherence: consider a light wave traveling along +X axis. Consider two different points A and B along the same wave train that is along +X axis.
If Φ(A) is phase of point A at any time and Φ(B) is phase of point B at any time, then
phase difference between these point is given by
Φ = Φ(A) – Φ(B)
If Φ is independent of time then points A and B are said to exhibit temporal coherence or longitudinal coherence
In other words, a beam of laser is said to exhibit temporal coherence if the phase difference of the waves crossing the two points lying on a plane parallel to the direction of the propagation of beam is independent of time.
a) spatial coherence: consider a light wave traveling along +X axis. Draw a line perpendicular to the direction of the beam. Consider two different points C and D on this line.
If Φ(C) is phase of point C at any time and Φ(D) is phase of point D at any time, then
phase difference between these point is given by
Φ = Φ(C) – Φ(D)
If Φ is independent of time then points C and D are said to exhibit spatial coherence or transverse coherence or lateral coherence.
In other words, a beam of laser is said to exhibit spatial coherence if the phase difference of the waves crossing the two points lying on a plane perpendicular to the direction of the propagation of beam is independent of time.
Answer:
There are two basic types of reference locality – temporal and spatial locality. Temporal locality refers to the reuse of specific data and/or resources within a relatively small time duration. Spatial locality (also termed data locality) refers to the use of data elements within relatively close storage locations.
Explanation: