You are given a passage. You need to construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) its answer is the whole paragraph. Avoid creating questions that can be answered correctly without actually understanding the paragraph.
Q: Causality prevents information from traveling "backward" in time, and is the most sacred tenant in physics. Relativistic time-dialiation (above) is certainly interesting, but there is no time-travel theory (quantum or otherwise) that won't be met with anything but snide remarks by a real physicist.
A:
What is the quantum time-travel theory?