Unitary causal decompositions, decompositions in terms of unitary circuits that do not require generalization to ‘extended’ or ‘routed’, are a central open problem in the study of causal structure in quantum theory. Researchers identify a combinatorial condition characterizing sets of no-influence constraints for which any unitary transformation admits a unitary causal decomposition representing the constraints.
Researchers define when a quantum circuit has a ‘causal’ structure
Unitary causal decompositions, decompositions in terms of unitary circuits that do not require generalization to ‘extended’ or ‘routed’, are a central open problem in the study of causal structure in quantum theory. Researchers identify a combinatorial condition characterizing sets of no-influence constraints for which any unitary transformation admits a unitary causal decomposition representing the constraints.