  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.

Quantum Physics;General Relativity and Quantum Cosmology;High Energy Physics - Theory