Compare Papers
Paper 1
Heralded state preparation in a superconducting qubit.
Johnson JE, Macklin C, Slichter DH, Vijay R, Weingarten EB, Clarke J, Siddiqi I.
- Year
- 2012
- Journal
- Phys Rev Lett
- DOI
- 10.1103/physrevlett.109.050506
- arXiv
- -
No abstract.
Open paperPaper 2
Essential Duality and Maximal Non-signalling Extensions in Algebraic Quantum Field Theory
Hassan Nasreddine
- Year
- 2026
- Journal
- arXiv preprint
- DOI
- arXiv:2605.00075
- arXiv
- 2605.00075
We show that, under additivity, the maximal von Neumann algebra extension of $\mathcal{A}(O)$ inside $B(\mathcal{H})$ whose inner automorphisms are non-signalling with respect to all spacelike-separated regions is $\mathcal{A}(O')'$. Consequently, $\mathcal{A}(O)$ is maximal with respect to this property if and only if essential duality holds. The proof is purely algebraic. When essential duality fails, we construct a proper extension all of whose inner automorphisms, and more generally all normal completely positive maps admitting Kraus operators in the algebra, are non-signalling. Under essential duality, any proper extension necessarily admits a signalling operation. An entropic formulation using Araki relative entropy provides a quantitative diagnostic of signalling, though it is not used in the proof. Additional structural results include the wedge-intersection identity $\mathcal{A}(O')' = \bigcap_{W \supset O}\mathcal{A}(W)$ and equivalent characterisations of essential duality. These results identify essential duality as an operational maximality condition within the given representation.
Open paper