All kinds of proposals have been put forth. At this point it would have to be a multi-generation ship.
But progress will happen. We went from ZERO powered flight to a manned lunar landing in 65 years, seven months.
None of these are practical proposals. The theories depend on energies that no one can conceive of generating.
I believe in basic research. No one can predict where basic research will lead. I HATE these stories that excoriate scientists that put crickets on treadmills.