But faster-than-light communication? Understanding why that’s not possible requires us to understand this key property of quantum physics: that forcing even part of an entangled system into one state or another doesn’t allow you to gain information about that forcing from measuring the remainder of the system.
yes, but we simply don't know if quantum field theory is correct.
Currently its the best theory we have bcs it always worked out (though our messurement isnt perfect, its more like an approximation)
But it is also pretty much the most complicated thing. And all patches we apply to it so it covers new discoveries make it even more complex
