Fig. 2: Floquet-engineered XXZ Heisenberg interaction.
From: Programmable Heisenberg interactions between Floquet qubits
a, Energy diagram of qubits Q1 and Q2 and pulse schematics for spin-exchange XY and spin–spin ZZ interactions. b, Chevron pattern showing the dependence of \({P}_{\left\vert 01\right\rangle }\) on the amplitude AXY and duration τg of pulses p1 and p2 for qubits initialized in \(\left\vert 10\right\rangle\). The pulses are applied at frequencies 40 MHz red(blue)-detuned from Q1(2)’s \(\left\vert 0\right\rangle \leftrightarrow \left\vert 1\right\rangle\) transition with DRAG coefficients λDRAG = −(+)0.6 and ramp time τr = 50 ns. c, Coherent oscillation between \(\left\vert 10\right\rangle\) and \(\left\vert 01\right\rangle\) for the optimal pulse amplitude AXY/2π = 65.2 MHz highlighted by the red dashed line in b. d, Extracted longitudinal coupling angle ΦZZ between the qubits after p1 and p3 are applied at 40 MHz red-detuned from Q1’s transition frequency. They are 200 ns long, with ramp time τr = 50 ns and DRAG coefficient λDRAG = −0.6. The amplitude of p1 is fixed at AXY/2π = 65.2 MHz, while the amplitude AZZ and phase φ of p3 are varied to tune the ZZ coupling rate. e, Extracted longitudinal coupling angle ΦZZ between the qubits after being subjected to all three pulses. The amplitude AXY of p1 and p2 is tuned to induce a full \(\left\vert 10\right\rangle \leftrightarrow \left\vert 01\right\rangle\) swap, while the amplitude AZZ and phase φ of p3 are varied to tune the ZZ rate during the swap.
