As of my last update in September 2021, there is no widely known concept or term called "Anderson loop" in physics or other scientific fields. It's possible that the term has emerged or gained significance after my last update, or it might refer to a specialized term used in a specific context or niche field.
If you could provide more context or specify the field in which "Anderson loop" is being used, I may be able to offer a more accurate explanation. Otherwise, it's important to note that terminologies can change or be limited to specific domains, so you might want to consult more recent sources or experts in the relevant field to get up-to-date information.