Simplicity of Continuous-Variable Observables

Determine where the unbounded interference fringe e^{ikx} associated with continuous-variable translations and momentum kicks lies with respect to simplicity.

Background

The paper extends its Pauli-observable analysis from qubits to qudits of prime dimension, where the proof of the tree-property result adapts. It then contrasts this finite-field setting with continuous variables, for which the commutation phase is the interference fringe e{ikx}.

The second paper established that this continuous-variable fringe is not NIP, but its status with respect to simplicity is left unresolved. The question asks whether the associated observable is simple, nonsimple, or belongs to some intermediate classification.

References

Where does the unbounded fringe lie with respect to simplicity?

— Classification of bipartite observables III: simplicity, mixtures and quantum error correction  (2610.22205 - Dueñez et al., 15 Oct 2026) in Section 10, Question 10.2, labeled ques:qudits