Semiclassical state on algebra of observables for de Sitter space and time reversal symmetry
The paper investigates how to recover semiclassical quantum field correlations in de Sitter space using heavy-clock states. It introduces a family of heavy-clock states that resolve issues with standard traces, showing that in the heavy-clock limit, $n$-point correlation functions match bulk quantum field correlations. Furthermore, it constructs an algebra $\mathcal{M}$ and a time-reversal invariant factor $\mathcal{F}$ by incorporating both forward and backward clock orientations.