Sainz AB Brunner N Cavalcanti D Skrzypczyk P Vértesi T 2015 The discovery of postquantum nonlocality, i.e., the existence of nonlocal correlations that are stronger than any quantum correlations but nevertheless consistent with the no-signaling principle, has deepened our understanding of the foundations of quantum theory. In this work, we investigate whether the phenomenon of Einstein-Podolsky-Rosen steering, a different form of quantum nonlocality, can also be generalized beyond quantum theory. While post-quantum steering does not exist in the bipartite case, we prove its existence in the case of three observers. Importantly, we show that postquantum steering is a genuinely new phenomenon, fundamentally different from postquantum nonlocality. Our results provide new insight into the nonlocal correlations of multipartite quantum systems. application/pdf https://sonar.ch/global/documents/255142 eng info:eu-repo/semantics/altIdentifier/doi/10.1103/PhysRevLett.115.190403 info:eu-repo/semantics/altIdentifier/pmid/26588364 info:eu-repo/semantics/openAccess Physical review letters. - 2015 Postquantum Steering. http://purl.org/coar/resource_type/c_6501