Long-range shuttling of a single electron bound to superfluid helium

Charge coupled devices (CCDs) have previously been shown to facilitate efficient, long-range transport of few electrons in gate-defined channels filled with superfluid helium. Such a scalable architecture with all-to-all connectivity has the potential to enable fast and coherent spin qubit transport. Previously, our electron sensing technique limited the electron sensitivity to small packets. Shifting the measurement frequency to 1 MHz (from 100 kHz), optimizing our bespoke cryogenic pre-amplifier circuit, and improving wiring now enables single electron sensitivity without the need for a tuned RF resonator. Here, we demonstrate charge shuttling of a total of 1 electron across 6 parallel, 580 μm long horizontal helium-filled channels to a second 680 μm long vertical helium-filled channel via T-junctions using 3-phase CCDs. The CCD device was fabricated utilizing a complementary-metal-oxide-silicon (CMOS) back-end-of-line (BEOL) metallization process at the Sandia National Laboratories MESA fab.