AWhat changed
Bohman and the BASE team sympathetically cooled a single proton by coupling it through a superconducting resonant circuit to laser-cooled beryllium ions in a separate Penning trap about nine centimetres away. Frequency spectra and controlled remote heating demonstrated energy exchange. Measurements of energy-dependent proton frequency shifts then showed a temperature reduction reaching 14.4±0.7 kelvin, relative to an effective circuit-noise temperature near 17 kelvin. The experiment extended sympathetic cooling beyond direct short-range Coulomb coupling.
Scientific scope
Bohman and the BASE team sympathetically cooled a single proton by coupling it through a superconducting resonant circuit to laser-cooled beryllium ions in a separate Penning trap about nine centimetres away. Frequency spectra and controlled remote heating demonstrated energy exchange. Measurements of energy-dependent proton frequency shifts then showed a temperature reduction reaching 14.4±0.7 kelvin, relative to an effective circuit-noise temperature near 17 kelvin. The experiment extended sympathetic cooling beyond direct short-range Coulomb coupling. The experiment measured the proton’s axial mode using calibrated, model-dependent frequency shifts. The quoted absolute final temperature, 2.6±2.5 kelvin, has much larger uncertainty than the temperature reduction. Other motional modes, antiproton cooling, ground-state preparation and improved fundamental-constant measurements were proposed extensions. The macroscopic circuit mode and trapped-particle motion were cooled; this does not mean the whole apparatus reached the inferred particle temperature.
Evidence
The linked original works support the scoped statement and contribution attribution. WRS has not independently replayed experiments or reconstructed a full mathematical proof. The experiment measured the proton’s axial mode using calibrated, model-dependent frequency shifts. The quoted absolute final temperature, 2.6±2.5 kelvin, has much larger uncertainty than the temperature reduction. Other motional modes, antiproton cooling, ground-state preparation and improved fundamental-constant measurements were proposed extensions. The macroscopic circuit mode and trapped-particle motion were cooled; this does not mean the whole apparatus reached the inferred particle temperature.
Contributors
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