Status of the wavefunction in QM after QFT? In QFT which is the continuation of QM the Quantum fields are considered as the final objective reality. If this is true why is there not a last and deceisive Interpretation of the wavefunction, which must be an artifact of the fields? 
 A: Interpretations don't disagree on what counts as a wavefunction. In fact, all interpretations of QM deal with the same projective Hilbert space, elements of which are none other than wavefunctions.
Interpretations disagree on how to, well, interpret wavefunctions. Specifically, it is the probabilistic predictions of quantum mechanics (the Born rule) which are logically interpreted differently.
Everything is exactly the same in QFT. QFT also has a Hilbert space of "wavefunctions" and operators that correspond to physical observables. For example, consider the state
$$ \left| \Psi \right> = \left( c_0 + a_p^{\dagger} c_1 \right) \left| 0 \right>. $$
Say you want to measure the number of particles in the field. The Born rule tells you that you will get 0 particles with probability $|c_0|^2$ and 1 particle with probability $|c_1|^2$ (assuming the coefficients and the states are normalized properly).
As far as the math is concerned, you've measured the state and you're done. The probabilities are all there is to know.
Now it's up to the interpretation to "make sense" of this unambiguous prediction. What happens during/after the measurement? Does the state collapse? If so, what happened to particle number / energy conservation? Are states/particles/fields real? Am I real?
