Ion–neutral-atom sympathetic cooling in a hybrid linear rf Paul and magneto-optical trap

Goodman, Douglas S.; Sivarajah, Ilamaran; Wells, James; Narducci, Frank A.; Smith, William Hayden

doi:10.1103/physreva.86.033408

Cited by 32 publications

(39 citation statements)

References 49 publications

(111 reference statements)

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“…Only recently it was shown, by the formalism of super-statistics, that this distribution indeed arises in the limit of multiple collisions [18]. The power-law tail of the distribution depends on the atom-ion mass ratio as well as the specific Paul trap parameters [19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Effect of ion-trap parameters on energy distributions of ultra-cold atom–ion mixtures

et al. 2020

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Experiments in which ultra-cold neutral atoms and charged ions are overlapped, constitute a new field in atomic and molecular physics, with applications ranging from studying out-of-equilibrium dynamics to simulating quantum many-body systems. The holy grail of ion-neutral systems is reaching the quantum low-energy scattering regime, known as the s-wave scattering. However, in most atom-ion systems, there is a fundamental limit that prohibits reaching this regime. This limit arises from the time-dependent trapping potential of the ion, the Paul trap, which sets a lower collision energy limit which is higher than the s-wave energy. In this work, we studied both theoretically and experimentally, the way the Paul trap parameters affect the energy distribution of an ion that is immersed in a bath of ultra-cold atoms. Heating rates and energy distributions of the ion are calculated for various trap parameters by a molecular dynamics (MD) simulation that takes into account the attractive atom-ion potential. The deviation of the energy distribution from a thermal one is discussed. Using the MD simulation, the heating dynamics for different atom-ion combinations is also investigated. In addition, we performed measurements of the heating rates of a ground-state cooled 88 Sr + ion that is immersed in an ultra-cold cloud of 87 Rb atoms, over a wide range of trap parameters, and compare our results to the MD simulation. Both the simulation and the experiment reveal no significant change in the heating for different parameters of the trap. However, in the experiment a slightly higher global heating is observed, relative to the simulation.

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Section: Introductionmentioning

confidence: 99%

Effect of ion-trap parameters on energy distributions of ultra-cold atom–ion mixtures

et al. 2020

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“…To ensure our extracted ion signal is entirely caused by Ca + , we continuously quench the Na + by applying a small oscillating voltage (1 V, ≈ 280 kHz) to the rods resonant with the second harmonic of the trapped Na + secular frequency, a process called mass-selective resonance quenching (MSRQ) [44]. With the MSRQ field on, the Na + ions are expelled from the trap within a few secular oscillation cycles [8,44]. We measure our total ion population after a variable co-trapping time by gating the end-segments into a dipole configuration and measuring the ion current incident on a megaspiraltron Channeltron electron multiplier (CEM).…”

Section: Apparatusmentioning

confidence: 99%

“…Cold to ultracold ion-neutral interactions were relatively unexplored until the creation of the hybrid trap [3], a device capable of co-trapping and cooling ions and neutral atoms [4]. Much early work with the hybrid traps focused on sympathetically cooling the translational motion of atomic ions and the internal internal degrees of freedom of molecular ions using the co-trapped neutral species [5][6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Measurement of charge exchange between Na and Ca+ in a hybrid trap

et al. 2019

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We present measurements of the charge-exchange reaction rate between neutral sodium (Na) and ionized calcium (Ca + ) in a hybrid atom-ion trap, which is comprised of a Na magneto-optical trap concentric with a linear Paul trap. Once the Na and Ca + are co-trapped, the reaction rate is measured by continuously quenching the reaction product Na + from the ion trap, and then destructively measuring the decay of the remaining ion population. The reactants' electronic state and temperature are experimentally controlled, allowing us to determine the four individual reactionrates between Na[S or P] and Ca + [S or D] at different collision energies. With the exception of the largest reaction-rate channel (Na[S] + Ca + [D]), our rates agree with classical Langevin rate limit. We have also found evidence of reactant collision-energy thresholds associated with two of the four entrance-channels.

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“…The top x-axis denotes the domain of this graph in terms of the plasma coupling parameter, , which is the ratio of potential to kinetic energy This behavior creates very rich dynamics for the cooling of ions, either by a laser or by a buffer gas. As the ions are cooled, the heating rate actually increases and whether or not the trapped sample can be cooled passed the liquid phase depends on whether or not the cooling rate can overwhelm this increasing heating rate [36]. By combining these treatments of heating and cooling in a hybrid trap, i.e.Q i−n andQ i−i , we arrive at an analytical model that describes the temperature of multiple trapped ions immersed in a buffer gas.…”

Section: Sympathetic Cooling Of Multiple Ionsmentioning

confidence: 99%

“…the lack of excess micromotion [27]; nonetheless, deviations from these assumptions can become important. In those cases, detailed molecular dynamics simulations like those performed in [25,29,35,36,38,39] are necessary.…”

Section: Caveats and Assumptions Of This Treatmentmentioning

confidence: 99%