I think hallucinogens might "turn the dial" on our quantum consciousness and "tune you in" to different parts of the signal, possibly meaning they can "entangle" the quantum structures in our minds with persistent information structures present somewhere. Maybe they do this randomly, or perhaps each drug is "frequency locked" to some particular part of the "spectrum" (not that I think it's anything so simple as a spectrum defined by a couple of parameters like 'virbation frequency' or whatever, but...), because there are often the same qualia reported for some chemicals independent of the person or setting (like DMT, apparently everybody on that saw an entity once).
Maybe the way chems affect us like this, is the same with getting into altered states without drugs. Or, to take a line from the matrix, "disrupt your input/output carrier signal" (as the red pill did).