Quantum Theory and Beyond

Carl Friedrich von Weizsäcker, Thomas Görnitz, Holger Lyre

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.

Alexander Streltsov

Introduction.- Quantum Theory.- Quantum Entanglement.- Quantum Correlations Beyond Entanglement.- Quantum Discord in Quantum Information Theory.- Outlook.

Inge Svein Helland

Richard Healey

In a recent archive post Shan Gao has argued that quantum theory is incompatible with relativity. He calls this a new proof beyond Bell's theorem, arguing elsewhere that it closes the superdeterminism loophole in Bell's theorem. Such strong claims must be backed up by irrefutable arguments. My aim in this post to the workshop "Beyond Bell's theorem" is to refute Gao's "proof" and to show how quantum theory is compatible with relativity theory and so why Gao's "proof" does not take us beyond Bell's theorem.

Berthold‐Georg Englert