secular matrix

[Entropia]

does anybody know the origins behind the *name* secular matrix?

i don't understand why a secular matrix would be called... secular.

[HallsofIvy]

First, the term "secular" matrix is not a mathematical term- it is a physics term. If you look up the word "secular" in a dictionary, you will find that one of its meanings has to do with time. The "secular matrix" in quantum physics is the matrix that represents the evolution of a an operator over time.

[selfAdjoint]

Saeculum is the Latin noun meaning "a long period of time", sometimes interpreted in modern times as a century. Nominative plural saecula, plural genitive saeculorum (as in the great seal of the US: Novus ordo saeculorum = "A new order for the ages")

Secular effects in Astronomy are those that take place over a long time, gradually accumulating.

The other meaning of secular, "not religious", comes from the division in the middle ages of topics that were religious = heavenly = outside of time, versus the other kind that were bound to the flow of time found here below.