sci.physics.particle

Hello All,


I am currently working through a copy of _The Physics of Time
Reversal_ by Sachs. Sachs often refers to an "equal time commutation
relation." I remember studying commutation relations in Bransden &
Joachain's textbook when I took quantum mechanics, but I do not recall
any mention of 'equal time' commutation relations.

If any one could give me a quick definition of this form of
commutation relations, I would greatly appreciate it.


Thank you.

LS Thomas