Not necessarily. While quantum mechanics and string theory are both areas of theoretical physics, they are distinct concepts and do not depend on each other for validation.
Quantum mechanics is a well-established and highly successful framework that describes the behavior of particles and systems at the microscopic level. It provides a probabilistic description of nature and has been extensively tested and confirmed through numerous experiments. If quantum mechanics were proven without a doubt, it would further solidify our understanding of the quantum realm, but it would not directly imply the existence of parallel worlds or different versions of ourselves.
String theory, on the other hand, is a theoretical framework that aims to unify quantum mechanics with gravity and other fundamental forces. It suggests that fundamental particles are not point-like entities but rather tiny vibrating strings. String theory does have the potential to accommodate the existence of parallel worlds or multiple universes, often referred to as the multiverse. However, string theory itself remains a highly speculative and mathematically complex area of research, and it has not been definitively proven or confirmed by experimental evidence thus far.
Therefore, while the confirmation of quantum mechanics would be a significant scientific achievement, it would not directly confirm or invalidate the ideas proposed by string theory, including the existence of parallel worlds or different versions of ourselves.