A Room-Temperature Extreme High Vacuum System for Trapped-Ion Quantum Information Processing

TL;DR

This paper describes the development of a room-temperature extreme high vacuum system optimized for long-duration trapped-ion quantum computing, achieving ultra-low pressures that support extended quantum processor operation without cryogenics.

Contribution

The authors engineered a room-temperature XHV system with optimized chamber design and outgassing reduction techniques, enabling long-term trapped-ion quantum processing at unprecedented vacuum levels.

Findings

Achieved chamber pressure of 1.5×10⁻¹² mbar, near measurement limit.

Measured ion collision intervals of approximately 1.9 hours.

Demonstrated extended quantum processor operation at room temperature.

Abstract

We present a room-temperature Extreme High Vacuum (XHV) system engineered to support the long-duration operation of a trapped-ion quantum processor. Background-gas collisions impose limitations on trapped-ion performance and scalability by interrupting algorithmic execution and, in some cases, ejecting ions from the trap. Using molecular-flow simulations, we optimize the chamber geometry, conductance pathways, and pumping configuration to maximize the effective pumping speed at the ion location. We perform high-temperature heat treatment of stainless steel vacuum components to achieve the desired outgassing rate, guided by quantitative relations of bulk diffusive processes, allowing us to reduce the \(\mathrm{H_2}\) outgassing load to the \(10^{-15}\,\mathrm{mbar\,l\,s^{-1}\,cm^{-2}}\) level. The final pressure in our chamber, measured by a hot cathode gauge, is \(1.5\times10^{-12}\,\mathrm{mbar}\), corresponding to the gauge's measurement limit. We measure the local pressure at the ion location by observing collision-induced reordering events in a long ion chain of mixed-isotope Yb\(^+\). From the observed reordering frequency, we extract the average interval between collisions to be \((1.9 \pm 0.1)\,\mathrm{hrs/ion}\). This corresponds to a local pressure of \((3.9 \pm 0.3)\times10^{-12}\,\mathrm{mbar}\) at the ion location, assuming that all collisions arise from background H\(_2\) molecules at room temperature. Our demonstration extends the continuous operation time of a quantum processor while maintaining the simplicity of a room-temperature system that does not require cryogenic apparatus.