Quantum physics allows for the concept of particles existing in two places at once. This is one common way of describing quantum superposition, although it does not fully capture the concept it describes. The phenomenon of superposition is well-established in the field, and has been demonstrated through many experiments with particles ranging from electrons to giant molecules. Large molecules composed of thousands of atoms can exist in two places at once, providing tangible evidence for the principles of superposition at macroscopic scales[6]. While the idea challenges classical intuition, it is a fundamental aspect of quantum mechanics. Sabine Hossenfelder, one of our YouTube favorites, had this informative post which explains that quantum superposition is more than simply being in two states at once, using qubits of a quantum computer to clarify the situation. This video includes a guest post within it as well, from Alvin Ash.
The ability of particles to be in multiple locations simultaneously is a consequence of their wave-like properties, as described by the mathematics of quantum mechanics[1][2][3].
Citations
[1] https://www.newscientist.com/article/2328087-can-particles-really-be-in-two-places-at-the-same-time/
[2] https://www.scientificamerican.com/article/giant-molecules-exist-in-two-places-at-once-in-unprecedented-quantum-experiment/
[3] https://www.uq.edu.au/news/article/2020/10/need-be-two-places-once-it-may-be-possible
[4] https://www.reddit.com/r/Physics/comments/ok6xfb/particles_are_not_in_two_places_at_once_quantum/
[5] https://www.youtube.com/watch?v=b05IeSlMMDw
[6] https://www.scientificamerican.com/article/giant-molecules-exist-in-two-places-at-once-in-unprecedented-quantum-experiment/