[niederman]

Whether there is any kind of action on the entangled counterpart is not actually answered by quantum mechanics, and depends on the interpretation. For example, in the Copenhagen interpretation there is an action (measuring one half of the pair causes the others waveform to instantly collapse), but in the Many Worlds interpretation there is no causal action, because observation is just a new entanglement between the observer and the entangled pair system.

[tbrownaw]

The math is clear that there is no information transfer.

The various interpretations are ways of trying to map what actually happens onto easily-understandable descriptions using standard classical-world vocabulary, which doesn't work very well because QM has fundamental differences from the macroscopic world that we live in and drive our language from. Where they disagree with eachother or with the math is because those mappings aren't perfect.

[niederman]

Just because there is no information transfer does not mean there is no action, it just means that this action does not break causality.