Electrons floating in vacuum provide a clean platform for quantum information processing owing to their isolation from material defects. In particular, electrons on solid neon have emerged as a promising qubit platform because of their potentially long coherence times. Here, toward spin-qubit realization, we couple a single electron on solid neon to a magnetic-field-compatible superconducting NbTiN nanowire resonator. We realize a charge qubit and demonstrate microwave readout and coherent control, with Rabi frequencies up to 76 MHz, an order of magnitude larger than in previous studies. Under strong driving, we observe a qubit frequency shift from nonlinear interactions with the intense microwave field. Deterministic electron trapping at an intended position remains challenging due to solid neon surface roughness; we characterize the electron's position from its differential coupling to distinct electrodes. Although not trapped at an intended position, our estimates indicate that spin-qubit demonstrations remain feasible.
Electrons floating in vacuum provide a clean platform for quantum information processing owing to their isolation from material defects. In particular, electrons on solid neon have emerged as a promising qubit platform because of their potentially long coherence times. Here, toward spin-qubit realization, we couple a single electron on solid neon to a magnetic-field-compatible superconducting NbTiN nanowire resonator. We realize a charge qubit and demonstrate microwave readout and coherent control, with Rabi frequencies up to 76 MHz, an order of magnitude larger than in previous studies. Under strong driving, we observe a qubit frequency shift from nonlinear interactions with the intense microwave field. Deterministic electron trapping at an intended position remains challenging due to solid neon surface roughness; we characterize the electron's position from its differential coupling to distinct electrodes. Although not trapped at an intended position, our estimates indicate that spin-qubit demonstrations remain feasible.
The promise of quantum computing has driven a persistent quest for new qubit platforms with long coherence, fast operation, and large scalability. Electrons, ubiquitous elementary particles of nonzero charge, spin, and mass, have commonly been perceived as paradigmatic local quantum information carriers. Despite superior controllability and configurability, their practical performance as qubits via either motional or spin states depends critically on their material environment. Here we report our experimental realization of a new qubit platform based upon isolated single electrons trapped on an ultraclean solid neon surface in vacuum. By integrating an electron trap in a circuit quantum electrodynamics architecture, we achieve strong coupling between the motional states of a single electron and microwave photons in an on-chip superconducting resonator. Qubit gate operations and dispersive readout are used to measure the energy relaxation time T1 of 15μs and phase coherence time T2 over 200 ns, indicating that the electron-on-solid-neon qubit already performs near the state of the art as a charge qubit.
The promise of quantum computing has driven a persistent quest for new qubit platforms with long coherence, fast operation, and large scalability. Electrons, ubiquitous elementary particles of nonzero charge, spin, and mass, have commonly been perceived as paradigmatic local quantum information carriers. Despite superior controllability and configurability, their practical performance as qubits via either motional or spin states depends critically on their material environment. Here we report our experimental realization of a new qubit platform based upon isolated single electrons trapped on an ultraclean solid neon surface in vacuum. By integrating an electron trap in a circuit quantum electrodynamics architecture, we achieve strong coupling between the motional states of a single electron and a single microwave photon in an on-chip superconducting resonator. Qubit gate operations and dispersive readout are implemented to measure the energy relaxation time T1 of 15μs and phase coherence time T2 over 200ns. These results indicate that the electron-on-solid-neon qubit already performs near the state of the art as a charge qubit.
Electrons floating on a solid neon exhibit long charge coherence times, making them attractive for hybrid quantum systems. When combined with high-quality, high-impedance superconducting resonators and a local magnetic field gradient, this platform enables strong charge--photon and spin--charge coupling-key ingredients for scalable spin qubit architectures. In this work, we demonstrate that NbTiN nanowire resonators maintain high quality factors around 10^5 after depositing solid neon onto the resonators and subsequently loading electrons onto the neon surface, validating their suitability for electrons-on-neon platforms. Building on these experimental results, we theoretically analyze micromagnet designs and coupling strategies that can enable spin-photon interactions in this platform. Our analysis outlines performance targets for next-generation devices, showing that, at the charge sweet spot, spin qubit gate fidelities exceeding 99.99% for single-qubit operations and 99.9% for two-qubit operations are achievable with natural neon.
Electrons trapped on solid neon surfaces serve as low-noise charge qubits with long coherence times and high operational fidelities. Such charge qubits offer full electrical control and compact device footprints, convenient for scaling up with quantum circuits. Realizing two-qubit gates on this platform is a critical step towards practical quantum information processing. In this work, we report the first experimental demonstration of coherent manipulation of multiple interacting electron-on-solid-neon (eNe) charge qubits. By exploiting the electrons naturally confined in close proximity by the surface structures of solid neon, we have achieved a direct qubit-qubit coupling strength of up to 62.5 MHz, as well as implemented cross-resonance (CR) and bSWAP two-qubit gates using global microwave drives. The natural electron confinement by solid neon mitigates the high-density-wiring challenge, simplifies the multi-qubit control, and establishes a unique path to scale up the eNe qubit platform.
Electron-on-neon (eNe) qubits have recently emerged as a compelling platform for quantum computing, which combines the vacuum isolation advantages of trapped-ion qubits with the scalability of superconducting circuits. In this system, electrons are trapped in vacuum above a solid neon film deposited on superconducting microwave resonators, where they exhibit strong coupling to the resonators, coherence times of ~0.1 ms, and single-qubit gate fidelities exceeding 99.97%. A central challenge, however, is the spontaneous binding of electrons to neon surface bumps. These bumps, originating from substrate roughness, vary in size: electrons on bumps of suitable sizes within the resonator can couple to microwave photons and function as qubits, whereas those on unfavorable bumps remain inactive yet contribute to background charge noise. Moreover, both the bump landscape and the sites where electrons bind differ from run to run, leading to variable qubit characteristics that hinder scalability. To address this challenging issue, we present an on-chip magnetic-levitation architecture in which arrays of solid-neon microparticles are suspended above the processor chip to act as electron carriers. This design eliminates substrate effects while retaining strong qubit-resonator coupling and supporting inter-qubit connectivity. Our analysis further shows that the qubit transition frequency can be tuned across the gigahertz range and its anharmonicity can reach ~0.8 GHz by tuning the resonator bias voltage. Together, these features suggest a promising pathway toward robust, reproducible, and scalable eNe-based quantum computing.
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.