I am preparing an interdisciplinary paper for publication in a leading physics journal. A preliminary version of this paper has been submitted to a conference in my field. Can the editors reject my paper based on this fact? In my field it would not be an issue. It is usually required that the journal paper expands on the contributions of the conference paper. In practice there a number of ways to overcome that requirement, so that it does not really matter. You need to submit a full paper to talk in a conference, so people use them as a first step of dissemination. But I do not know what is the relation between journal and conference papers in physics.