# Are there nonlinear models of quantum mechanics which forbid superluminal signaling?

What would a nonlinear model of quantum mechanics which forbids superluminal signaling look like? Of course, a nonlinear $\psi$-ontic theory with entangled states could have superluminal effects upon measurement, but even then, there's still the possibility that these effects could be invisible empirically. But what about nonlinear $\psi$-epistemic models when entangled states are measured locally?

The current answers at Why does nonlinearity in quantum mechanics lead to superluminal signaling? do not address this question.

• What is "a nonlinear model of quantum mechanics"? What is "superluminal signaling" in this case that it has to be explicitly forbidden, i.e. why would the no-communication theorem not hold? – ACuriousMind Mar 5 '15 at 17:33
• I repeat my question: What is "a nonlinear model of quantum mechanics"? Quantum mechanics is formalized by algebras of linear operators on Hilbert spaces. What does nonlinearity mean in this context? – ACuriousMind Mar 5 '15 at 17:56
• It's very sad to see a decent question downvoted for using unfamiliar technical terms. Voters please note that the question is referring to quite specialised literature in foundations of quantum mechanics, and as far as I can tell is a perfectly sensible one. – Nathaniel Mar 5 '15 at 23:34