Fig. 5
From: Entanglement between more than two hundred macroscopic atomic ensembles in a solid
Bound for maximum value of echo contrast R as a function of entanglement depth M. We assume P 1 = 3.5 × 10−3 and P 2 = 2.6 × 10−8 for the single-excitation and double-excitation probability, respectively, and the total number of ensembles (teeth) N = 564. The experimental value of the echo contrast R is shown as a green square
