Characterization of physical models producing approximate quantum Darwinism

Characterize a broader class of physical quantum systems and unitary evolutions that generate imperfect, approximate quantum Darwinism and redundant records of the past.

Background

The paper argues that perfect quantum Darwinism is associated with highly constrained, fine-tuned system–environment Hamiltonians, whereas realistic systems generally exhibit imperfect behavior. Although the paper introduces past redundancy as a framework capable of covering a wider range of models, it does not provide a general characterization of the systems that produce approximate quantum Darwinism.

References

To conclude, the class of models that generates imperfect, approximate QD is currently not known, and it is beyond doubts desirable to have a larger class of models capable of generating redundant records of the past.

— Redundant Records of the Past: Unifying Quantum Darwinism and Decoherent Histories  (2610.09845 - Strasberg, 7 Oct 2026) in Section 2.2, “Fine-tuned unitary evolution” (subsection “Open questions”)

While this class of quantum states is precisely characterized by a strongly decaying family of BCs, it remains unclear which physical situations reproduce it owing to the fact that one needs to understand higher order spatial correlations. This implies that results for the exponential decay of two-point correlations---which generically appear in one-dimensional lattice systems with finite-range interactions for, e.g., Gibbs states, matrix product states, ground states of gapped systems, systems with area law entanglement, etc.---do not automatically imply a quick decay of the BCs, although this seems a reasonable conjecture.

— Redundant Records of the Past: Unifying Quantum Darwinism and Decoherent Histories  (2610.09845 - Strasberg, 7 Oct 2026) in Section 5.1, “Single-event redundancy and correlated records”