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Eric Helgemo

Publications and source records attributed to Eric Helgemo.

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Deterministic single-electron trapping on solid neon using engineered dielectric surface geometry

Levitating electron qubit on the surface of solid neon has recently emerged as a promising and intrinsically noise-resilient platform for quantum information processing. Their ultra-clean, inert environment suppresses conventional decoherence pathways associated with lattice disorder, charge traps, and nuclear-spin baths that limit coherence in semiconductor qubits. Yet, uncontrolled surface features such as bumps, valleys, and electrode-defined gaps can bind electrons unintentionally, contributing charge noise and inducing spin-orbit coupling mediated decoherence. To address this challenge, we propose an engineered interface in which a dielectric layer is deposited beneath the solid neon to provide an atomically smooth template, eliminating surface-roughness induced trapping. By selectively etching this dielectric layer at desired qubit locations, deterministic potential minima can be engineered to reliably capture electrons while suppressing unwanted surface bound states. We perform large-scale Schrodinger and Poisson simulation to compare the existing and proposed strategies of electron trapping on neon, obtaining good agreement with recent experimental measurements.

quant-ph

Characterizing Neon Thin Film Growth with an NbTiN Superconducting Resonator Array

Electrons levitating above the surface of solid neon have recently emerged as a promising platform for high-quality qubits. The morphology and uniformity of the neon growth in these systems is crucial for qubit performance in a scalable architecture. Here we report on the controlled growth and characterization of thin solid neon films using multiplexed superconducting microwave resonators. By monitoring changes in the resonant frequency and internal quality factor ($Q_i$) of an array of frequency multiplexed quarter-wave coplanar waveguide resonators, we quantify the spatial uniformity of the film. A pulsed gas deposition protocol near the neon triple point results in repeatable film formation, generating measurable shifts in frequency and variations in $Q_i$ across the resonator array. Notably, introducing a post-deposition anneal at 12 K for one hour improves the film homogeneity, as shown by the reduced resonator-to-resonator variance in frequency and $Q_i$, consistent with enhanced wetting. These results demonstrate resonator-based metrology as an in-situ tool for characterising neon film growth, directly supporting the development of electron on inert quantum solid qubit platforms.

cond-mat.mes-hall