Figure 4
From: Finite-time quantum entanglement in propagating squeezed microwaves
Entanglement dephasing of propagating TMS states. The negativity kernel N k is plotted as a function of the delay time τ. Left graphs (a,b) show experimental data measured with the filter bandwidth Ω = 430 kHz. Right graphs (c,d) show the data obtained with Ω = 770 kHz. The red line in (a,c) marks the boundary between the entangled (N k > 0) and classical (N k < 0, separable) regions. The circles in (b,d) represent the experimental data, the lines show the corresponding fits using Eq. (2), S e values in the insets represent the experimental squeezing levels for both JPA1 and JPA2, S values denote the fitted squeezing levels, and n denotes the corresponding noise photon numbers. When not shown, statistical error bars are smaller than the symbol size.
