If an AI Creates a Work of Art, Who Owns the Rights to It?

Artificial intelligence is already capable of creating a staggering array of content. It can paint, write music, and put together a musical. It can write movies, angsty poems, and truly awful stand-up comedy. But does it have ownership over what it produces? For example, an AI at Google has managed to create sounds that humans have not heard before, merging characteristics of two different instruments and opening up a whole new toolbox for musicians to play around with.