  Quantum field theory is mostly known as the most advanced and well-developed
theory in physics, which combines quantum mechanics and special relativity
consistently. In this work, we study the spinless quantum field theory, namely
the Klein-Gordon equation, and we find that there exists a Dirac form of this
equation which predicts the existence of spinless fermion. For its
understanding, we start from the interpretation of quantum field based on the
concept of quantum scope, we also extract new meanings of wave-particle duality
and quantum statistics. The existence of spinless fermion is consistent with
spin-statistics theorem and also supersymmetry, and it leads to several new
kinds of interactions among elementary particles. Our work contributes to the
study of spinless quantum field theory and could have implications for the case
of higher spin.
