Rapid production of defect-free beryllium ion Coulomb crystals

二维单物种离子库仑晶体中拓扑缺陷的确定性工程

Deterministic engineering of topological defects in two-dimensional single-species ion Coulomb crystals

提出并数值验证了一种确定性协议，利用三维螺旋结构平面化在二维单物种离子库仑晶体中制备可控拓扑缺陷，实现单扭结和多扭结的可重复制备，并研究了缺陷相互作用与调控。

Dynamics of topological defects in ion Coulomb crystals

We study experimentally and theoretically the properties of structural defects (kink solitons) in two-dimensional ion Coulomb crystals. We show how different types of kink solitons with different physical properties can be realized, and transformed from one type into another by varying the aspect ratio of the trap confinement. Further, we discuss how impurities in ion Coulomb crystals, such as mass defects, can modify the dynamics of kink creation and their stability. For both pure and impure crystals, the experimentally observed kink dynamics are analyzed in detail and explained theoretically…

Nanofriction and motion of topological defects in self-organized ion Coulomb crystals

We study nanofriction in an ion Coulomb crystal under the presence of topological defects. We observe signatures of the pinning to sliding transition, namely the transverse vibrational soft mode signaling the transition and the symmetry breaking of the crystal configuration. We present details on experimental measurements and numerical simulations of this system, including the gaps in the hull function and the spectroscopy of the localized defect mode. We also investigate how external forces, such as those due to anharmonic potentials or differential light pressure, break the intrinsic crystal…

Observation of the 1S0 - 3P0 clock transition in 27Al+

We report for the first time, laser spectroscopy of the 1S0 - 3P0 clock transition in 27Al+. A single aluminum ion and a single beryllium ion are simultaneously confined in a linear Paul trap, coupled by their mutual Coulomb repulsion. This coupling allows the beryllium ion to sympathetically cool the aluminum ion, and also enables transfer of the aluminum's electronic state to the beryllium's hyperfine state, which can be measured with high fidelity. These techniques are applied to a measurement of the clock transition frequency, ν= 1 121 015 393 207 851(8) Hz. They are also used to measure t…

Trapping of Topological-Structural Defects in Coulomb Crystals

We study experimentally and theoretically structural defects which are formed during the transition from a laser cooled cloud to a Coulomb crystal, consisting of tens of ions in a linear radio frequency trap. We demonstrate the creation of predicted topological defects (`kinks') in purely two-dimensional crystals, and also find kinks which show novel dynamical features in a regime of parameters not considered before. The kinks are always observed at the centre of the trap, showing a large nonlinear localized excitation, and the probability of their occurrence surprisingly saturates at ~0.5. Si…

Multiscale quantum-defect theory and its application to atomic spectrum

We present a multiscale quantum-defect theory based on the first analytic solution for a two-scale long range potential consisting of a Coulomb potential and a polarization potential. In its application to atomic structure, the theory extends the systematic understanding of atomic Rydberg states, as afforded by the standard single-scale quantum-defect theory, to a much greater range of energies to include the first few excited states and even the ground state. Such a level of understanding has important implications not only on atomic structure, but also on the electronic structure of molecule…