This is another website that may be of use. Just fire it up for a while, pause the stream of numbers, and do what you will with them. It is guaranteed to be quantum-random.
This website claims to use a quantum random number generator (i.e. if you ask it for 6 random digits, each possible sequence of digits will appear with quantum measure 10^-6). Technically, it’s not quite guaranteed that using this to select a lottery ticket out of 10^6 possibilities will cause you to win with quantum measure 10^-6, since it is possible that your selection of a lottery ticket could affect which number wins, but it doesn’t seem likely that that would have a huge effect.
How recent does the branch have to be to count as “you”? There’s enough chaos that I’m pretty certain coinflips will turn out different a day after branching.
Only if either your selection of a lottery ticket or the lottery’s selection of a winning number are quantum-random. Which is usually not the case.
The former is trivial to achieve using random.org or similar.
What measures can a would-be MWI-lottery-winner take to create, or add, relevant quantum-randomness?
This is another website that may be of use. Just fire it up for a while, pause the stream of numbers, and do what you will with them. It is guaranteed to be quantum-random.
This website claims to use a quantum random number generator (i.e. if you ask it for 6 random digits, each possible sequence of digits will appear with quantum measure 10^-6). Technically, it’s not quite guaranteed that using this to select a lottery ticket out of 10^6 possibilities will cause you to win with quantum measure 10^-6, since it is possible that your selection of a lottery ticket could affect which number wins, but it doesn’t seem likely that that would have a huge effect.
How recent does the branch have to be to count as “you”? There’s enough chaos that I’m pretty certain coinflips will turn out different a day after branching.