Are provisional patent applications published by the U.S. Patent Office?
Provisional patent applications are NOT published by the U.S. Patent Office and are kept secret by the U.S. Patent Office. There are some exceptions to the secrecy of a provisional patent application such as when a non-provisional patent application claiming priority to the provisional patent application is published or granted as a patent. See an article by Neustel Law Offices titled Are Provisional Patent Applications Published for more information.