Renormalization of the energy–momentum tensor in non-commutative scalar field theory Original Research Article

We consider the one-loop renormalization of dimension four composite operators and the energy–momentum tensor in non-commutative φ4 scalar field theory. Proper operator bases are constructed and it is proved that the bare composite operators are expressed via renormalized ones, with the help of a mixing matrix, whose explicit form is calculated. The corresponding matrix elements turn out to differ from the commutative theory. The canonically defined energy–momentum tensor is not finite and must be replaced by the “improved” one, in order to provide finiteness. The suitable “improving” terms are found.