Figure 7

State fidelity for a simplified model of measurement, in which the state immediately collapses to the ideal post-measurement state, and is then acted upon by intrinsic decoherence and/or the coupling Lindbladian. The decay in the fidelity of the state \(\frac{1}{\sqrt {3}} ( \vert 100 \rangle + \vert 010 \rangle + \vert 001 \rangle )\) without the coupling Lindbladian (solid black line) coincides exactly with the case in which the coupling Lindbladian is present (black circles). The initial state \(\frac{1}{2} ( \vert 100 \rangle + \vert 100 \rangle + \vert 100 \rangle + \vert 111 \rangle )\) produces a markedly different effect, its fidelity decaying much more quickly when the coupling Lindbladian is present (solid blue line) than when it is absent (dashed black line).