  In this work, our prime objective is to study non-locality and long-range
effects of two-body correlation using quantum entanglement from the various
information-theoretic measures in the static patch of de Sitter space using a
two-body Open Quantum System (OQS). The OQS is described by a system of two
entangled atoms, surrounded by a thermal bath, which is modelled by a massless
probe scalar field. Firstly, we partially trace over the bath field and
construct the Gorini Kossakowski Sudarshan Lindblad (GSKL) master equation,
which describes the time evolution of the reduced subsystem density matrix.
This GSKL master equation is characterized by two components, these are-Spin
chain interaction Hamiltonian and the Lindbladian. To fix the form of both of
them, we compute the Wightman functions for probe massless scalar field. Using
this result along with the large time equilibrium behaviour we obtain the
analytical solution for reduced density matrix. Further using this solution we
evaluate various entanglement measures, namely Von-Neumann entropy, R$e'$nyi
entropy, logarithmic negativity, entanglement of formation, concurrence and
quantum discord for the two atomic subsystems on the static patch of De-Sitter
space. Finally, we have studied the violation of Bell-CHSH inequality, which is
the key ingredient to study non-locality in primordial cosmology.
