Bonus - warp drive science alluded to by Elizabeth Bear in this book...
by chance I came across this web page
in which the warp drive theory chosen by Elizabeth Bear in this book (and its companion, set in the same universe but so far as I can tell, not directly related) is described.
Some fun bits
Miguel Alcubierre, a theoretical physicist in 1994 developed a theory called the Alcubierre drive. He created a bubble within space-time that would twist distances making it possible for anything to travel long distances within the bubble. Most people thought this made perfect theoretical sense, but practically it wasn’t workable.
[it] would require a large amount of mass-energy to make the warp drive function. To propel the spacecraft at such as level, you would need the mass equivalent to that of Jupiter.
Dr. Harold Sonny White, a NASA mechanical engineer, and physicist is still trying to find ways to solve the mass-energy that is required. He believes by bending ways in physics, it is likely possible to bring down the mass-energy requirement mentioned in the Alcubierre theory. He also suggested there might be slight possibilities to change the shape of the ring of the negative mass to enable mass requirement of about 700kg.
White is now leading a team of physicists and engineers in NASA to build the White-Juday Warp Field Interferometer. It is a beam splitting interferometer which can easily detect and generate the tiniest warp bubble. Perhaps this might not instantly get you over to Andromeda Galaxy, but eventually, you’ll get there when needed.