Experimental demonstration of non-bilocality with truly independent sources and strict locality constraints

The ongoing interest in creating a secure global quantum network culminated recently in the demonstration of transcontinental quantum communication(1). There is a pressing need to examine the properties attached to a quantum network architecture from multiple perspectives, including physics foundations(2), communication security(3), the efficient use of resources and innovative technological application(4,5). Here, we present an experimental realization of a five-node quantum network, in which quantum sources at two nodes deliver entangled photon pairs to three measurement nodes. With relevant events between five nodes separated space-like, we demonstrate violation of the Bell inequality and bilocal inequality(6), with the locality, measurement independence and quantum source independence loopholes closed simultaneously in a quantum network. This experimental realization may be valuable for the design and implementation of future quantum networks.