Bell's theorem. Experimental tests and implications

TLDR

Bell's theorem advances the conceptual foundations of quantum mechanics. The theorem shows that essentially all local realistic theories can be tested with a single experimental arrangement, and their predictions must differ significantly from those of quantum mechanics. Experimental results refute the predictions of local realistic theories and favor quantum mechanics, implying either abandonment of realism or a dramatic revision of spacetime concepts.

Abstract

Bell's theorem represents a significant advance in understanding the conceptual foundations of quantum mechanics. The theorem shows that essentially all local theories of natural phenomena that are formulated within the framework of realism may be tested using a single experimental arrangement. Moreover, the predictions by those theories must significantly differ from those by quantum mechanics. Experimental results evidently refute the theorem's predictions for these theories and favour those of quantum mechanics. The conclusions are philosophically startling: either one must totally abandon the realistic philosophy of most working scientists, or dramatically revise out concept of space-time.