Strong driving of artificial atoms

We investigated the dynamics of a superconducting two level artificial atom under strong resonant driving. In the weak driving regime, the dynamics of the system consists of the well known Rabi oscillations between energy eigenstates. For stronger driving, when the driving strength is comparable to the atomic transition frequency, the proper framework to describe the dynamics is Floquet theory. We explored experimentally and theoretically the transition between the weak and strong driving regime where Floquet theory applies.

weak to strong Rabi
Oscillations of atomic excited state probability (left) and the corresponding Fourier transform (right) for a three different driving strength values. The atomic transition frequency is 2.29 GHz.

We found that high fidelity gates are possible in the strong driving regime using an effect that we called FIESTA (Floquet Interference Efficient Suppression of Transitions in the Adiabatic basis).

[1] Deng et al., Phys. Rev. Lett. 115, 133601 (2015).
[2] Deng et al., Phys. Rev. A 94, 032323 (2016).