Vanishing trace anomaly in flat spacetime

Understand

Quantum scale invariant regularization is a variant of dimensional regularization where the renormalization scale is treated as a dynamical field.

• But, rather than be regarded as a novel regularization method on par with dimensional regularization, momentum cutoff, Pauli-Villars etc., it should be understood as a way to define a subset in the infinite space of nonrenormalizable models of certain type.
• The subset realizes the demand that renormalization scale, along with any other dimensionful parameters, should be interpreted as a dynamical field's homogeneous background.
• This restriction is most straightforwardly implemented using dimensional regularization but it can hypothetically be imposed with any regularization method.