arXiv subjects

Kenneth M. Hughes

Publications and source records attributed to Kenneth M. Hughes.

3 recordsLinked to original sources

arXiv2026

A high-flux atomic strontium oven with light-driven flux modulation

A high-flux source of strontium atoms is required for cold atom quantum technology applications. We present a re-entrant oven design that avoids the need for any vacuum feed-throughs and has an inherent temperature gradient to guard against clogging of the nozzle. The nozzle is fabricated by micro-machining of fused silica using selective laser etching; this specialised technique is capable of making many thousands of fine microchannels and is suitable for batch production. Operating with only electrical heating, using <20W of electrical power, a total flux of $8(1)\times 10^{14}$ atoms/s is achieved at an oven temperature of 475°C, of which we estimate $1.8(2)\times 10^{13}$ atoms/s could be captured. A heated in-vacuum sapphire window grants optical access directly opposite the oven, and can be cleared of metallization without breaking vacuum. We used this optical access to modulate the flux of the atomic beam by direct illumination of the nozzle and the strontium metal with high-power laser light. Heating by laser light increased the useful flux by a factor of up to 16(3) on a timescale of 40s, and a factor of 2.5(5) on a timescale of 1s. This flux modulation serves to increase the operating lifetime of the oven. We report experimental measurements of the performance of the oven in long-term operation over many months.

physics.atom-ph↗

arXiv2026

A High-Flux Source of Cold Strontium with a Loading Rate of $4 \times 10^{10}$ atoms/s for Open Release

We present a high-flux source of cold strontium atoms based on a two-dimensional magneto-optical trap (2D MOT) and a Zeeman slower. We use the source to load a 3D MOT in a separate science chamber, observing a loading rate of $4 \times 10^{10}$ atoms/s -- to our knowledge, the highest reported loading flux for strontium. To characterise the vacuum pressure in the science chamber, we load the atoms into a magnetic trap and measure a lifetime of between 8 and 24 seconds, depending on oven temperature. Finally, we characterise the atom flux and velocity distributions from the oven and from the 2D MOT source, finding reasonable agreement with models in the free molecular flow regime. Our results show it is possible to readily produce a cold strontium flux at comparable levels to alkali species, at oven temperatures compatible with long-term operation, and at vacuum pressures suitable for state-of-the-art quantum experiments. We make our design available at no cost, to benefit researchers in the quantum community.

cond-mat.quant-gas↗

arXiv2024

A single-photon large-momentum-transfer atom interferometry scheme for Sr or Yb atoms with application to determining the fine-structure constant

The leading experimental determinations of the fine-structure constant, $α$, currently rely on atomic photon-recoil measurements from Ramsey-Bordé atom interferometry with large momentum transfer to provide an absolute mass measurement. We propose an experimental scheme for an intermediate-scale differential atom interferometer to measure the photon-recoil of neutral atomic species with a single-photon optical clock transition. We calculate trajectories for our scheme that optimise the recoil phase while nullifying the undesired gravity-gradient phase by considering independently launching two clouds of ultracold atoms with the appropriate initial conditions. For Sr and Yb, we find an atom interferometer of height 3m to be sufficient for an absolute mass measurement precision of $Δm / m \sim 1\times 10^{-11}$ with current technology. Such a precise measurement (the first of its kind for Sr or Yb) would halve the uncertainty in $α$ -- an uncertainty that would no longer be limited by an absolute mass measurement. The removal of this limitation would allow the uncertainty in $α$ to be reduced by a factor of 10 by corresponding improvements in relative mass measurements, thus paving the way for higher-precision tests of the Standard Model of particle physics.

physics.atom-ph↗