Fig. 4: AQT Cascade.
From: Adiabatic quantum state transfer in a semiconductor quantum-dot spin chain
a Quantum circuit diagram for the experiment. We initialize the spins as \(\left|{S}_{12}{\downarrow }_{3}{\uparrow }_{4}\right\rangle\). Applying two AQT steps transfers the product state of spins 3–4 to 1–2, and the singlet state of spins 1–2 to spins 3–4. b Exchange-coupling parameters as a function of time for the AQT steps shown in (a), where T is the Hamiltonian interpolation time and 0 < t < T. c Singlet-return probabilities for the left pair \(({P}_{\,\text{S}}^{\text{L}\,})\) and the right pair \(({P}_{\,\text{S}}^{\text{R}\,})\) when f = + 1. d Data for f = −1. Simulations neglecting and including known sources of error are overlaid in each panel. The insets in (c) and (d) show prominent exchange oscillations between spins 1–2 and singlet-triplet oscillations associated with spins 3–4, after the AQT cascade described in (a), providing evidence of successful transfer of spin states. Each data point represents the average of 256 single-shot measurements.
