On the Limits of a Space‐Time Description and the Physical Meaning of Phase Space in a Nonlocal Continuum

In a previous paper we derived an uncertainty relation for nonlocal fields by showing that the physical localization width in nonlocal quantum field theory is broadened by the response kernel generated from the entire‐function regulator. In this follow up we reinterpret that result as just the position‐sector limit of a more symmetric statement because we did not take into account the inherent nonlocality of momentum. We find and we prove under normalized, centered response kernels for both position and momentum the variance laws and derive the corresponding nonlocal phase‐space uncertainty relation. The result still preserves the conclusions of the original paper while strengthening the interpretation as nonlocal quantum field theory implies not merely a minimal measurable length, but a finite phase‐space cell. We also explore experimental routes to test the theory.