Dynamics of axialized laser-cooled ions in a Penning trap

Abstract

We report the experimental characterization of axialization -a method of reducing the magnetron motion of a small number of ions stored in a Penning trap. This is an important step in the investigation of the suitability of Penning traps for quantum information processing. The magnetron motion was coupled to the laser-cooled modified cyclotron motion by the application of a nearresonant oscillating quadrupole potential (the "axialization drive"). Measurement of cooling rates of the radial motions of the ions showed an order-of-magnitude increase in the damping rate of the magnetron motion with the axialization drive applied. The experimental results are in good qualitative agreement with a recent theoretical study. In particular, a classical avoided crossing was observed in the motional frequencies as the axialization drive frequency was swept through the optimum value, proving that axialization is indeed a resonant effect.

Professor Danny Segal – scientist and scholar

“…Axialisation is a technique used in other fields that was adapted by Danny for use with laser-cooled ions. It made it possible to work with single ions in a much more robust way and we have continued to make extensive use of this technique since [10,11].…”

Zero-dynamics principle for perfect quantum memory in linear networks

“…time varying) in order to realize high quality quantum memory. For instance, in [24][25][26][27], the authors consider the time varying system matrices depending on the control field with frequency ω t ( ), which is optimized via a heuristic method. On the other hand, in this paper, we assume that Ω and C are time varying, but they are constant in each stage of the memory procedure; that is, they are piecewise constant.…”

“…For some typical quantum memories such as EIT and off-resonant Raman memories, we can explicitly formulate this problem; that is, the question is what is the optimal temporal shape of the pulsed light field carrying the input state. This optimization problem is very important and actually has been deeply investigated in several papers; for instance, towards the most efficient atomic memory with EIT, in [24][25][26][27] the input wave packet as well as the controllable Rabi frequency ω t ( ) (see the second paragraph) are carefully designed, although the method is a heuristic one based on iterative tuning of the parameters. It is also notable that the so-called rising exponential type function is found as an effective pulse shape [28][29][30].…”

“…In this paper, we consider a general passive linear system, which models a wide variety of systems such as optical systems [18-20, 22, 34, 35], nano-mechanical oscillators [21,36,37], vibration mode of a trapped particle [38,39], and atomic ensembles [24][25][26][27][28][29][40][41][42][43][44][45]. As mentioned before, the system is assumed to contain a tunable memory subsystem; that is, by tuning a certain parameter, we can switch opening/closing of the memory subsystem, which is DF during the storage period.…”

Эффективный Ротационный Потенциал Молекулярных Ионов В Плоской Радиочастотной Ловушке

“…Тем не менее, локализация и манипулирование сложными заряженными объектами сопряжена с большим количеством проблем, поскольку динамика пространственно-неоднородных заряженных частиц значительно зависит от пространственной структуры таких объектов [6]. Таким образом, даже одна дополнительная вращательная степень свободы в сравнении со случаем локализации одноатомной молекулы значительно усложняет движение частицы в пространстве, приводя к изменению частотных спектров (в классическом рассмотрении), энергетических уровней (в квантово-механическом рассмотрении), что, к примеру, исключает возможность эффективного лазерного охлаждения [7].…”