Dynamics of Transmon Ionization
Ross Shillito, Alexandru Petrescu, Joachim Cohen, Jackson Beall, Markus Hauru, Martin Ganahl, Adam G. M. Lewis, Guifré Vidal, Alexandre Blais
Abstract
Qubit measurement is an essential step in any quantum computation. In circuit quantum electrodynamics, a leading quantum computer architecture, qubit readout is commonly one of the longest and lowest-fidelity processes. The authors numerically explore the dynamics of a driven transmon-resonator system under strong, nearly resonant measurement drives to better understand this issue. They find clear signs of transmon ``ionization'', in which the qubit escapes its confining potential under the influence of the drive, and semiclassical methods then reveal the mechanism. This approach can be used to optimize circuit parameters, suppress these spurious effects, and increase readout fidelity.