Okay. I just don't understand. Are you saying Quantum Computers are also implemented without assuming the computations run in parallel universe?
I don't know what he's saying, but I'm saying that the answer to your question is "Yes," unless quantum computers behave differently than expected.
Correct. The laws of quantum mechanics (used for building quantum computers among other things) make very little assumptions on the nature of the universe, and support multiple interpretations, many-worlds being only one of them.
Quantum mechanics is a tool to calculate observable values, and this tool works very successfully without needing to make strong assumptions about the nature of the universe.