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Sympathetic cooling of protons and antiprotons with a common endcap Penning trap

M. Bohman, Andreas H. Mooser, Georg L. Schneider, Natalie Schön, M. Wiesinger, Harrington, J., Takashi Higuchi, Hiroki Nagahama, C. Smorra, Stefan Sellner, K. Blaum, Y. Matsuda, W. Quint, J. Walz, S. Ulmer

Published Jan 1, 2018• 22 citations
OpenAlex

Abstract

We present an experiment to sympathetically cool single protons and antiprotons in a Penningtrap by resonantly coupling the particles to laser cooled beryllium ions using a common endcaptechnique. Our analysis shows that preparation of (anti)protons at mK temperatures on timescalesof tens of seconds is feasible. Successful implementation of the technique will have immediate andsignificant impact on high-precision comparisons of the fundamental properties of protons andantiprotons. This in turn will provide stringent tests of the fundamental symmetries of the StandardModel.

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Sympathetic cooling of protons and antiprotons with a common endcap Penning trap

M. Bohman, A. Mooser, G. Schneider +12 more

We present an experiment to sympathetically cool single protons and antiprotons in a Penning trap by resonantly coupling the particles to laser cooled beryllium ions using a common endcap technique. Our analysis shows that preparation of (anti)protons at mK temperatures on timescales of tens of seconds is feasible. Successful implementation of the technique will have immediate and significant impact on high-precision comparisons of the fundamental properties of protons and antiprotons. This in turn will provide stringent tests of the fundamental symmetries of the Standard Model.

arXiv:1709.00433•Journal of Modern Optics•Dec 4, 2017•38 citations

Cryogenic Penning-Trap Apparatus for Precision Experiments with Sympathetically Cooled (Anti)Protons

Malte Niemann, Teresa Meiners, J. Mielke +17 more

Current precision experiments with single (anti)protons to test CPT symmetry progress at a rapid pace, but are complicated by the need to cool particles to sub-thermal energies. We describe a cryogenic Penning-trap setup for $^9$Be$^+$ ions designed to allow coupling of single (anti)protons to laser-cooled atomic ions for sympathetic cooling and quantum logic spectroscopy. We report on trapping and laser cooling of clouds and single $^9$Be$^+$ ions. We discuss prospects for a microfabricated trap to allow coupling of single (anti)protons to laser-cooled $^9$Be$^+$ ions for sympathetic laser cooling to sub-mK temperatures on ms time scales.

arXiv:2107.08433•CPT and Lorentz Symmetry•Apr 7, 2020•0 citations

Cryogenic 9Be+ Penning trap for precision measurements with (anti-)protons

M Niemann, T Meiners, J Mielke +4 more

Abstract Cooling and detection schemes using laser cooling and methods of quantum logic can contribute to high precision CPT symmetry tests in the baryonic sector. This work introduces an experiment to sympathetically cool protons and antiprotons using the Coulomb interaction with a ion trapped in a nearby but separate potential well. We have designed and set up an apparatus to show such coupling between two identical ions for the first time in a Penning trap. In this paper, we present evidence for successful loading and Doppler cooling of clouds and single ions. Our coupling scheme has applications in a range of high-precision measurements in Penning traps and has the potential to substantially improve motional control in these experiments.

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Characterisation of an experiment for sympathetic cooling and coupling of ions in a cryogenic Penning trap

Teresa Meiners

The comparison of the g-factors of the proton and the antiproton is a stringent test of CPT invariance. The state-of-the-art method for the determination of the (anti-)proton's g-factor is the application of the continuous Stern-Gerlach effect. With this method, precisions in the low parts per billion regime could be achieved. However, preparation times for cold enough particles are on the order of minutes to hours. The implementation of sympathetic cooling using a co-trapped atomic ion could lead to preparation times in the milliseconds regime. Furthermore, the applicability of sympathetic cooling would enable an alternative readout scheme using quantum logic methods. This thesis presents a Penning trap system that is designed for ground state cooling, adiabatic transport, and motional coupling of single 9Be+ ions. It has been built in a modular manner, giving the option of adapting it for motional coupling and sympathetic cooling of single (anti-)protons. In the course of this work, the prerequisites for motional coupling of 9Be+ ions have been fulfilled: A cloud of 9Be+ ions was cooled to a temperature of 1.7~mK applying Doppler cooling. The achieved temperature is about three times the Doppler limit which is 0.5~mK for beryllium ions. Furthermore, a scheme for reproducible loading of the trap and reducing the particle number was developed. Finally, first transport in our apparatus was demonstrated with clouds of beryllium ions. The method used for that is directly applicable to single ions. The results of this work pave the way towards adiabatic transport of single 9Be+ ions, which is crucial for sympathetic cooling of (anti-)protons in a double-well potential as well as for implementing quantum logic spectroscopy with single (anti-)protons.

•Jan 1, 2021•0 citations

Sympathetic cooling of a trapped proton mediated by an LC circuit

M. Bohman, Valentin Grunhofer, C. Smorra +18 more

Efficient cooling of trapped charged particles is essential to many fundamental physics experiments1,2, to high-precision metrology3,4 and to quantum technology5,6. Until now, sympathetic cooling has required close-range Coulomb interactions7,8, but there has been a sustained desire to bring laser-cooling techniques to particles in macroscopically separated traps5,9,10, extending quantum control techniques to previously inaccessible particles such as highly charged ions, molecular ions and antimatter. Here we demonstrate sympathetic cooling of a single proton using laser-cooled Be+ ions in spatially separated Penning traps. The traps are connected by a superconducting LC circuit that enables energy exchange over a distance of 9 cm. We also demonstrate the cooling of a resonant mode of a macroscopic LC circuit with laser-cooled ions and sympathetic cooling of an individually trapped proton, reaching temperatures far below the environmental temperature. Notably, as this technique uses only image–current interactions, it can be easily applied to an experiment with antiprotons1, facilitating improved precision in matter–antimatter comparisons11 and dark matter searches12,13.

•Jan 1, 2021•31 citations

Sympathetic Cooling of a Proton with Resonant Image Current Coupling

M. Bohman

This thesis is the realization of the long standing goal of sympathetically cooling single particles with image currents. Particles with no electronic structure such as the bare proton or antiproton, are not amenable to standard laser cooling and ma-nipulation techniques and until now have been cooled only by coupling to cryogenictank circuits. In measurements of the proton and antiprotong-factor however, theenergy splitting used to read out the particle’s spin state is larger than thermal en-ergy fluctuations and special techniques are required to perform the measurement.The technique developed here uses a cloud of laser cooled beryllium ions to sym-pathetically cool a single proton by coupling to, and cooling a mode of the tank circuit. The use of this circuit resonantly enhances the energy exchange between the trapped particles and allows the cooling ions to be separated from the particle of interest over arbitrary distances. This technique, is the first demonstration of sympathetic cooling of a proton and a macroscopic LC circuit to below 25% of the environment temperature.Sympathetically cooled protons and antiprotons with this method enable an improved g-factor measurement by increasing the duty cycle of the experiment. This will further our understanding of matter-antimatter asymmetry by constraining CPT odd new physics and enhancing sensitivity to even more exotic physics. More-over, the technique presented here has general applications in experiments with trapped charged particles, enabling coupling of a large number of ions, distributed in many separated trapping regions to a single cold resonator.

•Jan 1, 2021•3 citations
We present an experiment to sympathetically cool single protons and antiprotons in a Penningtrap by resonantly coupling the particles to laser cooled beryllium ions using a common endcaptechnique. Our analysis shows that preparation of (anti)protons at mK temperatures on timescalesof tens of seconds is feasible. Successful implementation of the technique will have immediate andsignificant impact on high-precision comparisons of the fundamental properties of protons andantiprotons. This in turn will provide stringent tests of the fundamental symmetries of the StandardModel.
We present an experiment to sympathetically cool single protons and antiprotons in a Penning trap by resonantly coupling the particles to laser cooled beryllium ions using a common endcap technique. Our analysis shows that preparation of (anti)protons at mK temperatures on timescales of tens of seconds is feasible. Successful implementation of the technique will have immediate and significant impact on high-precision comparisons of the fundamental properties of protons and antiprotons. This in turn will provide stringent tests of the fundamental symmetries of the Standard Model.
Current precision experiments with single (anti)protons to test CPT symmetry progress at a rapid pace, but are complicated by the need to cool particles to sub-thermal energies. We describe a cryogenic Penning-trap setup for 9^99Be+^++ ions designed to allow coupling of single (anti)protons to laser-cooled atomic ions for sympathetic cooling and quantum logic spectroscopy. We report on trapping and laser cooling of clouds and single 9^99Be+^++ ions. We discuss prospects for a microfabricated trap to allow coupling of single (anti)protons to laser-cooled 9^99Be+^++ ions for sympathetic laser cooling to sub-mK temperatures on ms time scales.
Abstract Cooling and detection schemes using laser cooling and methods of quantum logic can contribute to high precision CPT symmetry tests in the baryonic sector. This work introduces an experiment to sympathetically cool protons and antiprotons using the Coulomb interaction with a ion trapped in a nearby but separate potential well. We have designed and set up an apparatus to show such coupling between two identical ions for the first time in a Penning trap. In this paper, we present evidence for successful loading and Doppler cooling of clouds and single ions. Our coupling scheme has applications in a range of high-precision measurements in Penning traps and has the potential to substantially improve motional control in these experiments.
The comparison of the g-factors of the proton and the antiproton is a stringent test of CPT invariance. The state-of-the-art method for the determination of the (anti-)proton's g-factor is the application of the continuous Stern-Gerlach effect. With this method, precisions in the low parts per billion regime could be achieved. However, preparation times for cold enough particles are on the order of minutes to hours. The implementation of sympathetic cooling using a co-trapped atomic ion could lead to preparation times in the milliseconds regime. Furthermore, the applicability of sympathetic cooling would enable an alternative readout scheme using quantum logic methods. This thesis presents a Penning trap system that is designed for ground state cooling, adiabatic transport, and motional coupling of single 9Be+ ions. It has been built in a modular manner, giving the option of adapting it for motional coupling and sympathetic cooling of single (anti-)protons. In the course of this work, the prerequisites for motional coupling of 9Be+ ions have been fulfilled: A cloud of 9Be+ ions was cooled to a temperature of 1.7~mK applying Doppler cooling. The achieved temperature is about three times the Doppler limit which is 0.5~mK for beryllium ions. Furthermore, a scheme for reproducible loading of the trap and reducing the particle number was developed. Finally, first transport in our apparatus was demonstrated with clouds of beryllium ions. The method used for that is directly applicable to single ions. The results of this work pave the way towards adiabatic transport of single 9Be+ ions, which is crucial for sympathetic cooling of (anti-)protons in a double-well potential as well as for implementing quantum logic spectroscopy with single (anti-)protons.
Efficient cooling of trapped charged particles is essential to many fundamental physics experiments1,2, to high-precision metrology3,4 and to quantum technology5,6. Until now, sympathetic cooling has required close-range Coulomb interactions7,8, but there has been a sustained desire to bring laser-cooling techniques to particles in macroscopically separated traps5,9,10, extending quantum control techniques to previously inaccessible particles such as highly charged ions, molecular ions and antimatter. Here we demonstrate sympathetic cooling of a single proton using laser-cooled Be+ ions in spatially separated Penning traps. The traps are connected by a superconducting LC circuit that enables energy exchange over a distance of 9 cm. We also demonstrate the cooling of a resonant mode of a macroscopic LC circuit with laser-cooled ions and sympathetic cooling of an individually trapped proton, reaching temperatures far below the environmental temperature. Notably, as this technique uses only image–current interactions, it can be easily applied to an experiment with antiprotons1, facilitating improved precision in matter–antimatter comparisons11 and dark matter searches12,13.
This thesis is the realization of the long standing goal of sympathetically cooling single particles with image currents. Particles with no electronic structure such as the bare proton or antiproton, are not amenable to standard laser cooling and ma-nipulation techniques and until now have been cooled only by coupling to cryogenictank circuits. In measurements of the proton and antiprotong-factor however, theenergy splitting used to read out the particle’s spin state is larger than thermal en-ergy fluctuations and special techniques are required to perform the measurement.The technique developed here uses a cloud of laser cooled beryllium ions to sym-pathetically cool a single proton by coupling to, and cooling a mode of the tank circuit. The use of this circuit resonantly enhances the energy exchange between the trapped particles and allows the cooling ions to be separated from the particle of interest over arbitrary distances. This technique, is the first demonstration of sympathetic cooling of a proton and a macroscopic LC circuit to below 25% of the environment temperature.Sympathetically cooled protons and antiprotons with this method enable an improved g-factor measurement by increasing the duty cycle of the experiment. This will further our understanding of matter-antimatter asymmetry by constraining CPT odd new physics and enhancing sensitivity to even more exotic physics. More-over, the technique presented here has general applications in experiments with trapped charged particles, enabling coupling of a large number of ions, distributed in many separated trapping regions to a single cold resonator.