The article seems particularly hermetic, especially wrt "bilocal causality" which doesn't seem to occur as a phrase before Dec 2016[1].
The piece tells us "bilocal causality" is
> a concept that is related to the more standard local causality, except that it accounts for the precise way in which physical systems are initially generated.
and later references
> a new type of Bell inequality that accounts for the fact that the two sources of states used in the experiment are independent, the so-called bilocality assumption.
If, like me, you find this non-obvious, you may like to get some background from an earlier paper[2] (different authors) which has a seemingly less opaque description of bilocality than the phys.org article:
> Nowadays, fast progress towards advanced demonstrations
of quantum communication networks, involving quantum repeaters [10] based on entanglement swappings [11] and quantum memories [12], are underway in many labs around the world. In these future quantum networks, several independent sources of entangled qubit pairs will distribute entanglement to partners who will then connect their neighbours by performing joint measurements on two (or more) qubits, each entangled with one neighbouring qubit, as illustrated for the simple case of three partners in Fig. 1. Such experiments have an interesting feature that has so far received little attention in previous works on nonlocality: the multipartite correlations between the measurement results at each site do not originate from a single multipartite entangled state, but from a series
of bipartite entangled states that are initially independent and uncorrelated from each other; i.e., there is not a unique initial joint state (the analogue of λ in a locally causal model) that is responsible for the observed correlations, but these are instead created from smaller systems through joint measurements. [...]
The piece tells us "bilocal causality" is
> a concept that is related to the more standard local causality, except that it accounts for the precise way in which physical systems are initially generated.
and later references
> a new type of Bell inequality that accounts for the fact that the two sources of states used in the experiment are independent, the so-called bilocality assumption.
If, like me, you find this non-obvious, you may like to get some background from an earlier paper[2] (different authors) which has a seemingly less opaque description of bilocality than the phys.org article:
> Nowadays, fast progress towards advanced demonstrations of quantum communication networks, involving quantum repeaters [10] based on entanglement swappings [11] and quantum memories [12], are underway in many labs around the world. In these future quantum networks, several independent sources of entangled qubit pairs will distribute entanglement to partners who will then connect their neighbours by performing joint measurements on two (or more) qubits, each entangled with one neighbouring qubit, as illustrated for the simple case of three partners in Fig. 1. Such experiments have an interesting feature that has so far received little attention in previous works on nonlocality: the multipartite correlations between the measurement results at each site do not originate from a single multipartite entangled state, but from a series of bipartite entangled states that are initially independent and uncorrelated from each other; i.e., there is not a unique initial joint state (the analogue of λ in a locally causal model) that is responsible for the observed correlations, but these are instead created from smaller systems through joint measurements. [...]
1: https://www.google.com/search?q=%22bilocal+causality%22+-%22...
2: https://arxiv.org/pdf/1112.4502.pdf