Bogoliubov causality condition is a causality condition for scattering matrix (S-matrix) in axiomatic quantum field theory. The condition was introduced in axiomatic quantum field theory by Nikolay Bogolyubov in 1955.
In axiomatic quantum theory, S-matrix is considered as a functional of a function
g
:
M
→
[
0
,
1
]
defined on the Minkowski space
M
. This function characterizes the intensity of the interaction in different space-time regions: the value
g
(
x
)
=
0
at a point
x
corresponds to the absence of interaction in
x
,
g
(
x
)
=
1
corresponds to the most intense interaction, and values between 0 and 1 correspond to incomplete interaction at
x
. For two points
x
,
y
∈
M
, the notation
x
≤
y
means that
x
causally precedes
y
.
