[jessriedel]

That paper is discussing nonlinear quantum mechanics, models of which are almost always internally inconsistent. More importantly, it's just speculation; the kind of quantum mechanics that has been confirmed in the lab is linear.

It's well known that quantum mechanics does not violate causality (when defined appropriately in terms of actual observations).

[Practicality]

But my whole point was speculating that it's possible, not that it's proven to be true. So of course I am citing speculative sources, this is speculation... :\

[jessriedel]

Although it may sound like it, I don't believe it's splitting hairs to draw an important distinction between (a) speculation that might be observable in our lifetime, or might have relevance to stock trading, and (b) speculation that has fundamental inconsistencies with deep principles on which the entire known body of physics knowledge is based, and which would revolutionize our understanding of the universe and the nature of reality if true. Here's another way to say it: time travel is strictly less crazy than acausality.

Sorry, not trying to be a buzzkill :)

[Practicality]

Not a problem. I prefer learning to being right :)