Seminarium Fizyki Materii Skondensowanej

Conservation principles are essential to describe and quantify mechanical processes. Classically, the conservation holds objectively because the description of reality can be considered independent of observation. In quantum mechanics, however, invasive observations change quantities drastically, even those conserved classically. Interestingly, we find that the non-conservation is manifest even in weakly measured correlations if some of the observables do not commute with the conserved quantity. Our observation casts some doubt on the fundamental compatibility of conservation laws and quantum objectivity.