We describe a simple and fast method for simulating observed images of ion Coulomb crystals. In doing so, cold elastic collisions between Coulomb crystals and virtual very light atoms are implemented in a molecular dynamics (MD) simulation code. Such an approach reproduces the observed images of Coulomb crystals by obtaining density plots of the statistics of existence of each ion. The simple method has the advantage of short computing time in comparison with previous calculation methods. As a demonstration of the simulation, the formation of a planar Coulomb crystal with a small number of ions has been investigated in detail in a linear ion trap both experimentally and by simulation. However, also large Coulomb crystals including up to 1400 ions have been photographed and simulated to extract the secular temperature and the number of ions. For medium-sized crystals, a comparison between experiments and calculations has been performed. Moreover, an MD simulation of the sympathetic cooling of small molecular ions was performed in order to test the possibility of extracting the temperature and the number of refrigerated molecular ions from crystal images of laser-cooled ions. Such information is basic to studying ultracold ion-molecule reactions using ion Coulomb crystals including sympathetically cooled molecular ions.We describe a simple and fast method for simulating observed images of ion Coulomb crystals. In doing so, cold elastic collisions between Coulomb crystals and virtual very light atoms are implemented in a molecular dynamics (MD) simulation code. Such an approach reproduces the observed images of Coulomb crystals by obtaining density plots of the statistics of existence of each ion. The simple method has the advantage of short computing time in comparison with previous calculation methods. As a demonstration of the simulation, the formation of a planar Coulomb crystal with a small number of ions has been investigated in detail in a linear ion trap both experimentally and by simulation. However, also large Coulomb crystals including up to 1400 ions have been photographed and simulated to extract the secular temperature and the number of ions. For medium-sized crystals, a comparison between experiments and calculations has been performed. Moreover, an MD simulation of the sympathetic cooling of small molecular ions was performed in order to test the possibility of extracting the temperature and the number of refrigerated molecular ions from crystal images of laser-cooled ions. Such information is basic to studying ultracold ion-molecule reactions using ion Coulomb crystals including sympathetically cooled molecular ions.

Physical Review AJan 28, 201052 citations

Sympathetic cooling of molecular ions in a surface-electrode ion trap

Arezoo Mokhberi, Stefan Willitsch

We report the sympathetic cooling and Coulomb crystallization of molecular ions above the surface of an ion-trap chip. ${\mathrm{N}}_{2}^{+}$ and ${\mathrm{CaH}}^{+}$ ions were confined in a surface-electrode radio-frequency (rf) ion trap and cooled by the interaction with laser-cooled ${\mathrm{Ca}}^{+}$ ions to secular translational temperatures in the millikelvin range. The configuration of trapping potentials generated by the surface electrodes enabled the formation of planar bicomponent Coulomb crystals and the spatial separation of the molecular from the atomic ions on the chip. The structural and thermal properties of the Coulomb crystals were characterized using molecular dynamics simulations. The present study extends chip-based trapping techniques to cold molecular ions with potential applications in mass spectrometry, chemistry, quantum information science, and spectroscopy.We report the sympathetic cooling and Coulomb crystallization of molecular ions above the surface of an ion-trap chip. ${\mathrm{N}}_{2}^{+}$ and ${\mathrm{CaH}}^{+}$ ions were confined in a surface-electrode radio-frequency (rf) ion trap and cooled by the interaction with laser-cooled ${\mathrm{Ca}}^{+}$ ions to secular translational temperatures in the millikelvin range. The configuration of trapping potentials generated by the surface electrodes enabled the formation of planar bicomponent Coulomb crystals and the spatial separation of the molecular from the atomic ions on the chip. The structural and thermal properties of the Coulomb crystals were characterized using molecular dynamics simulations. The present study extends chip-based trapping techniques to cold molecular ions with potential applications in mass spectrometry, chemistry, quantum information science, and spectroscopy.

arXiv:1404.4292Physical Review AAug 4, 201410 citations

Ion-based quantum simulation of many-body electron–electron Coulomb interaction

Da-Wei Luo, P. V. Pyshkin, Michele Modugno +3 more

Quantum Information ProcessingAug 3, 20181 citation

We report the sympathetic cooling and Coulomb crystallization of molecular ions above the surface of an ion-trap chip.

{\mathrm{N}}_{2}^{+}

and

{\mathrm{CaH}}^{+}

ions were confined in a surface-electrode radio-frequency (rf) ion trap and cooled by the interaction with laser-cooled

{\mathrm{Ca}}^{+}

ions to secular translational temperatures in the millikelvin range. The configuration of trapping potentials generated by the surface electrodes enabled the formation of planar bicomponent Coulomb crystals and the spatial separation of the molecular from the atomic ions on the chip. The structural and thermal properties of the Coulomb crystals were characterized using molecular dynamics simulations. The present study extends chip-based trapping techniques to cold molecular ions with potential applications in mass spectrometry, chemistry, quantum information science, and spectroscopy.