Reduction of correlations by quantum indefinite causal structure

Understand

We show that quantum indefinite causal structure generically reduce two-party correlations.

• For significant indefiniteness in the causal structure captured by some general conditions, the correlation is shown to be reduced down to zero.
• The result offers an operational model-independent ultraviolet regularization mechanism.
• It may be applied to various approaches of quantum gravity that allow quantum indefinite spacetime causal structure.