Figure 3
From: Finite-time quantum entanglement in propagating squeezed microwaves
Experimental marginal distributions of the Wigner function of TMS states created via interference of two orthogonally squeezed single-mode states with the squeezing levels S1 ≃ S2 ≃ 8 dB in a hybrid ring. The quantities p and q are dimensionless variables representing quadratures of the electromagnetic field. Color reflects the quasiprobability amplitude. Left box (a) illustrates transformation of the hybrid ring inputs in the self-correlated subspaces {p1, q1} and {p2, q2}. Its respective outputs show no quantum signatures and coincide with thermal states with an average number of photons nTMS = 2.7. Right box (b) depicts the output distributions in the cross-correlated subspaces {q2, p1} and {p2, q1} which uncover quantum entanglement in the form of two-mode squeezing with STMS = 7.2 dB and corresponds to the negativity kernel of N k = 2.1.
