Coupling a single electron on helium to a superconducting resonator

Electrons on helium is a unique two-dimensional system on the interface of superfluid He-4 and vacuum. Both the motional state and spin state of a single electron on helium have been proposed as candidates for long-lived qubits. To trap a single electron on helium, we use a small electrostatic trap located at the voltage anti-node of a superconducting microwave resonator. By adjusting the trap potential we are able to consistently load between one and four electrons and detect their spectroscopic features through the resonator. In particular, in the single electron regime a large resonator frequency shift reveals when the electron motional frequency is resonant and allows us to extract an electron-photon coupling of ~ 10 MHz. I will highlight our latest experiments leading towards the development of an electron on helium qubit.