Title: Quantum decoherence from entanglement during inflation,
Abstract: We study the primary entanglement effect on the decoherence of fields reduced
density matrix which are in interaction with another fields or independent mode
functions. We show that the primary entanglement has a significant role in
decoherence of the system quantum state. We find that the existence of
entanglement could couple dynamical equations coming from Schrödinger
equation. We show if one wants to see no effect of the entanglement parameter
in decoherence then interaction terms in Hamiltonian can not be independent
from each other. Generally, including the primary entanglement destroys the
independence of the interaction terms. Our results could be generalized to
every scalar quantum field theory with a well defined quantization in a given
curved space time.