  We show single photon and electron interferences can be calculated without
quantum-superposition states by using tensor form (covariant quantization).
From the analysis results, the scalar potential which correspond to an
indefinite metric vector forms an oscillatory field and causes the
interferences. The results clarify the concept of quantum-superposition states
is not required for the description of the interference, which leads to an
improved understanding of the uncertainty principle and resolution of paradox
of reduction of the wave packet, elimination of infinite zero-point energy and
derivation of spontaneous symmetry breaking. The results conclude Quantum
theory is a kind of deterministic physics without "probabilistic
interpretation".
