'Genuine Decoherence' and Macroscopic Superposition

[StevieTNZ]

By 'Genuine Decoherence' - I mean collapse of the wave function by a theory and its mathematical equations.

If a micro system encounters a macroscopic apparatus - in collapse theories a definite state appears for both the apparatus and system, but after a tiny time since the system entangled with the apparatus.

For genuine decoherence to occur and be predicted in a future theory, does it need to allow macroscopic superpositions (even if they last for a short time)?

Of course we can keep current QM formalism and have hidden variables to remove the measurement problem.

 

[Nugatory]

Decoherence says that macroscopic superpositions will very quickly resolve themselves into mixed states - Schrödinger's cat wiil very quickly decohere from a macroscopic superposition of dead and alive to a mixed state in which the cat is either dead or alive as surely as a tossed coin is heads or tails.

Thus decoherence doesn't preclude macroscopic superpositions, it just says they don't last very long. This differs from collapse interpretations in which a macroscopic superposition (Schrödinger's both dead and alive cat, for example) can persist until an observation forces the collapse.