Beyond Quantumization

Ciarán M. Lee

David Deutsch, ARTUR K. EKERT

William M. Honig

Edwin Peter Lobo, Sahil Gopalkrishna Naik, Samrat Sen +3 more

Physical theories constrained with local quantum structure and satisfying the no-signalling principle can allow beyond-quantum global states. In a standard Bell experiment, correlations obtained from any such beyond-quantum bipartite state can always be reproduced by quantum states and measurements, suggesting local quantum structure and no-signalling to be the axioms to isolate quantum correlations. In this letter, however, we show that if the Bell experiment is generalized to allow local quantum inputs, then beyond-quantum correlations can be generated by every beyond-quantum state. This gives us a way to certify beyond-quantumness of locally quantum no-signalling theories and in turn suggests requirement of additional information principles along with local quantum structure and no-signalling principle to isolate quantum correlations. More importantly, our work establishes that the additional principle(s) must be sensitive to the quantum signature of local inputs. We also generalize our results to multipartite locally quantum no-signalling theories and further analyze some interesting implications.

Hayato Arai, Baichu Yu, Masahito Hayashi

There is a theoretical possibility of beyond-quantum nonlocality in the framework of general probabilistic theories. The authors give a protocol to detect beyond-quantum nonlocality with standard quantum devices.