The Schrodinger equation, which describes the space-time evolution of a free particle, is a continuous function whose amplitude is the probability for detecting a particle at a particular position. If you consider the Schrodinger equation to be a true reflection of reality, then a particle can be considered (potentially) in an infinite number of positions. However, with suitable restrictions, it is possible to confine a particle to one of two positions but that;s simply a special case of the more general solution.
All that being said, there is no accepted interpretation of the Schrodinger equation that is an unambiguous description of reality. There are some interpretations (pilot wave, many worlds) that would say that a particle has a definite position and that it does not exist in multiple positions at the same time.
All that being said, there is no accepted interpretation of the Schrodinger equation that is an unambiguous description of reality. There are some interpretations (pilot wave, many worlds) that would say that a particle has a definite position and that it does not exist in multiple positions at the same time.