Towards Strong Coupling in Single Electron-on-Helium Systems

Single electrons trapped on the surface of superfluid helium (EonHe) are a unique and versatile platform for hybrid quantum information science. An attractive approach for single electron manipulation and readout is to leverage cavity QED techniques by coupling a superconducting resonator to an electron’s translational motion, and eventually, the spin [1]. Recent work has achieved coupling between a superconducting resonator and a single electron’s translational motion [2], limited primarily by dephasing mechanisms due to helium surface vibrations. In this work, we make strides towards strong coupling by making use of high impedance TiN thin film resonators in tandem with a geometry that significantly reduces the contribution of helium surface vibrations to the single electron linewidth. We present our latest experiments in the platform towards strongly coupling the translational state of a single electron to a superconducting resonator.

[1] Schuster et al., Phys. Rev. Lett. 105, 040503 (2010).

[2] Koolstra et al., Nat. Commun. 10, 5235 (2019).