Twisted coalgebra structure of poincare group and noncommutative qft on the moyal space

الملخص EN

We study the consequences of twisting the coalgebra structure of Poincar´e group in a quantum field theory on a flat space-time.

First, we construct a tensor product representation space compatible with the twisting and the corresponding creation and annihilation operators.

Then, we show that a covariant field linear in creation and annihilation operators does not exist.

Relaxing the linearity condition, a covariant field can be determined.

We show that it is related to the untwisted field by a unitary transformation and the resulting n-point functions coincide with the untwisted ones.

We also show that invariance under the twisted symmetry can be realized using the covariant field with the usual product or by a non-covariant field with a Moyal product.

The resulting S-matrix elements are shown to coincide with the untwisted ones up to a momenta dependent phase.