# Does self-induced collapse limit the size of a quantum computer?

This question is related to this question, but I'm specifically interested in self-induced collapse. Suppose that the size of a quantum system alone somehow leads to a projection of the state (a "collapse of the wavefunction"), i.e. the collapse is self-induced by the system, without any interaction with an environment which ultimately has some effect on the knowledge of the observer. This is not standard quantum mechanics, but answers to this question lead me to think that this is a common assumption. My question is: Would this imply that large quantum computers are impossible? Maybe there are even known limits in some models?

• What are the circumstances under which a subsystem comes to 'realise' that it is part of a larger quantum computing system? An answer to this might be necessary to rule out approaches to overcoming the collapse through error correction, to realise universal QC. – Niel de Beaudrap Jan 11 '19 at 18:27
• @NieldeBeaudrap I guess that depends on the collapse model, for the "Penrose interpretation" there seems to be some threshold energy of some form, such that superpositions of vastly different energies are impossible? – M. Stern Jan 11 '19 at 21:32