  We consider wavefunctions which are non-negative in some tensor product
basis. We study what possible teleportation can occur in such wavefunctions,
giving a complete answer in some cases (when one system is a qubit) and partial
answers elsewhere. We use this to show that a one-dimensional wavefunction
which is non-negative and has zero correlation length can be written in a
"coherent Gibbs state" form, as explained later. We conjecture that such holds
in higher dimensions. Additionally, some results are provided on possible
teleportation in general wavefunctions, explaining how Schmidt coefficients
before measurement limit the possible Schmidt coefficients after measurement,
and on the absence of a "generalized area law"\cite{genarealaw} even for
Hamiltonians with no sign problem.
  One of the motivations for this work is an attempt to prove a conjecture
about ground state wavefunctions which have an "intrinsic" sign problem that
cannot be removed by any quantum circuit. We show a weaker version of this,
showing that the sign problem is intrinsic for commuting Hamiltonians in the
same phase as the double semion model under the technical assumption that TQO-2
holds\cite{tqo2}.
