Query: Experimental investigation of planar ion traps,

Candidate papers:

abstract: Chiaverini et al. [Quantum Inf. Comput. 5, 419 (2005) recently suggested a linear Paul trap geometry for ion trap quantum computation that places all of the electrodes in a plane. Such planar ion traps are compatible with modern semiconductor fabrication techniques and can be scaled to make compact, many zone traps. In this paper we present an experimental realization of planar ion traps using electrodes on a printed circuit board to trap linear chains of tens of charged particles of $0.44\phantom{\rule{0.3em}{0ex}\mathrm{\ensuremath{\mu}\mathrm{m} diameter in a vacuum of $15\phantom{\rule{0.3em}{0ex}\mathrm{Pa}\phantom{\rule{0.3em}{0ex}{10}\ensuremath{ }1}\phantom{\rule{0.3em}{0ex}\mathrm{torr} With these traps we address concerns about the low trap depth of planar ion traps and develop control electrode layouts for moving ions between trap zones without facing some of the technical difficulties involved in an atomic ion trap experiment. Specifically, we use a trap with 36 zones (77 electrodes) arranged in a cross to demonstrate loading from a traditional four rod linear Paul trap, linear ion movement, splitting and joining of ion chains, and movement of ions through intersections. We further propose an additional dc biased electrode above the trap which increases the trap depth dramatically, and a planar ion trap geometry that generates a two dimensional lattice of point Paul traps.
author_names: C E Pearson

David R Leibrandt

Waseem S Bakr

William Mallard

Kenneth R Brown

Isaac L Chuang
title: Experimental investigation of planar ion traps
year: 2006

author_names: C E Pearson

David R Leibrandt
title: Experimental investigation of planar ion traps (12 pages)
year: 2006

abstract: The accurate characterization of eigenmodes and eigenfrequencies of two dimensional ion crystals provides the foundation for the use of such structures for quantum simulation purposes. We present a combined experimental and theoretical study of two dimensional ion crystals. We demonstrate that standard pseudopotential theory accurately predicts the positions of the ions and the location of structural transitions between different crystal configurations. However, pseudopotential theory is insufficient to determine eigenfrequencies of the two dimensional ion crystals accurately but shows significant deviations from the experimental data obtained from resolved sideband spectroscopy. Agreement at the level of 2.5x10( 3) is found with the full time dependent Coulomb theory using the Floquet Lyapunov approach and the effect is understood from the dynamics of two dimensional ion crystals in the Paul trap. The results represent initial steps towards an exploitation of these structures for quantum simulation schemes.
author_names: Henning Kaufmann

Stefan Ulm

Georg Jacob

U Poschinger

Haggai Landa

Alex Retzker

Martin Bodo Plenio

Ferdinand Schmidt-Kaler
title: Precise experimental investigation of eigenmodes in a planar ion crystal.
venue: Physical review letters
year: 2012

author_names: Vytenis Benetis
title: EXPERIMENTAL AND COMPUTATIONAL INVESTIGATION OF PLANAR ION DRAG MICROPUMP GEOMETRICAL DESIGN PARAMETERS
year: 2005

abstract: The uncertainty of the ac Stark shift due to thermal radiation represents a major contribution to the systematic uncertainty budget of state of the art optical atomic clocks. In the case of optical clocks based on trapped ions, the thermal behavior of the rf driven ion trap must be precisely known. This determination is even more difficult when scalable linear ion traps are used. Such traps enable a more advanced control of multiple ions and have become a platform for new applications in quantum metrology, simulation, and computation. Nevertheless, their complex structure makes it more difficult to precisely determine its temperature in operation and thus the related systematic uncertainty. We present here scalable linear ion traps for optical clocks, which exhibit very low temperature rise under operation. We use a finite element model refined with experimental measurements to determine the thermal distribution in the ion trap and the temperature at the position of the ions. The trap temperature is investigated at different rf drive frequencies and amplitudes with an infrared camera and integrated temperature sensors. We show that for typical trapping parameters for In+ Al+ Lu+ Ca+ Sr+ or Yb+ ions, the temperature rise at the position of the ions resulting from rf heating of the trap stays below 700 mK and can be controlled with an uncertainty on the order of a few 100 mK maximum. The corresponding uncertainty of the trap related blackbody radiation shift is in the low 10 19 and even 10 20 regime for 171Yb+(E3) and 115In+ respectively.
author_names: T Nordmann

A Didier

Miroslav Dolezal

Petr Balling

Tobias Burgermeister

T E Mehlstaubler
title: Sub kelvin temperature management in ion traps for optical clocks.
venue: The Review of scientific instruments
year: 2020

abstract: Motivated by recent developments in ion trap design and fabrication, we investigate the stability of the motion of an ion in asymmetrical, planar versions of the linear Paul trap. The equations of motion of an ion in such a trap are generally coupled due to a nonzero relative angle th between the principal axes of RF and DC fields, invalidating the assumptions behind the standard stability analysis for symmetric Paul traps. Using numerical methods, we obtain stability diagrams for the coupled system for various values of th, generalizing the standard q a stability diagrams. We then use multi scale perturbation theory to obtain approximate formulas for the boundaries of the primary stability region and check our formulas against results from numerical analysis. Our results show that while the primary stability region is quite robust to changes in th, a secondary stability region is highly variable, joining the primary stability region at the special case of th=45deg, which results in a significantly enlarged sta.
author_names: Fayaz A Shaikh

Arkadas Ozakin
title: Stability analysis of ion motion in asymmetric planar ion traps
year: 2012

abstract: In this thesis, we investigate a new geometry of Paul trap with electrodes in a plane. These planar ion traps are compatible with modern silicon microfabrication, and can be scaled up to large arrays with multiple trapping zones. We implement these designs on printed circuit boards with macroscopic ions, allowing us to study the traps while avoiding the experimental challenges of atomic ion traps. We discuss the dynamics of ions in the traps using both numerical and analytical means. Scalable traps are of interest to the quantum computing community as a potential implementation of a large scale quantum computer. However, there are concerns about the low trap depth relative to a conventional trap of the same size. We address this in three ways, first by introducing a conductive plane above the trap to increase its depth, then by using a deeper trap with a three dimensional electrode geometry to load the trap, and finally by loading the trap directly while using a buffer gas to slow down energetic ions so that the trap can capture them. Also of concern is the ability of the trap to move ions through arms and intersections. We demonstrate these movement operations, and study properties of the linear trap including the secular frequency and geometric factors between planar and four rod traps. The precision of atomic ion trap experiments makes them sensitive to background gas pressure at levels that are undetectable to conventional gauges. The capacity for integrating circuitry and optical elements with the trap could anticipate complete ion trap experiments performed by a single chip, and a new technology for an integrated pressure gauge would be immensely useful if the pressure detection can shown to be feasible and repeatable. In a point planar trap, we observe ion motion to determine background gas pressure, demonstrating an application that could bring planar ion traps into much wider use. Thesis Supervisor: Isaac L. Chuang Title: Associate Professor of Physics
author_names: C E Pearson
title: Theory and application of planar ion traps
year: 2006

author_names: Stephen A Lammert

James Mitchell Wells
title: EXPERIMENTAL INVESTIGATION INTO THE PERFORMANCE OF ION TRAPS USING AIR VERSUS HELIUM AS THE BUFFER GAS
year: 1996

abstract: A hybrid model, which consists of a fluid module, a sheath module and an ion Monte Carlo module, is employed to investigate the dependence of ion energy and angular distributions (IEDs and IADs) on the inductively coupled plasma (ICP) power, pressure, gas ratio, bias power and bias frequency in Ar/O2 discharges. The results indicate that the bimodal distribution appears as bias power increases or bias frequency decreases. Moreover, the low and high energy peaks of IEDs move to higher energy with the rise of bias power and O2 content. Whereas, an opposite tendency is observed with the increase of ICP power and pressure. For IADs, it is clear that a larger percentage of ions incident on the electrode have a smaller deflection angle by increasing bias power or decreasing pressure, and a similar evolution is observed with the decline of bias frequency. Besides, the better collimation of ions is obtained at larger O2 concentration, but ICP power only has little influence on IADs. In order to validate the model, a comparison between the simulated IEDs and those measured by a retarding field energy analyzer has been done, and shows a good agreement. The results obtained in this work could help us to gain more insight into the dependence of IEDs and IADs on the discharge parameters, which is of significant importance in the improvement of the etching rate and anisotropy.
author_names: Yu-Ru Zhang

Zhuan Zhao

Chan Xue

Fei Gao

You-Nian Wang
title: Ion energy and angular distributions in planar Ar/O2 inductively coupled plasmas: hybrid simulation and experimental validation
venue: Journal of Physics D: Applied Physics
year: 2019

abstract: In order to realize the full potential of ion trap quantum computers, an improved understanding is required of the motional heating that trapped ions experience. Experimental studies of the temperature frequency and ion electrode distance dependence of the electric field noise responsible for motional heating, as well as the noise before and after ion bombardment cleaning of trap electrodes, suggest that fluctuations of adsorbate dipoles are a likely source of so called "anomalous heating," or motional heating of the trapped ions at a rate much higher than the Johnson noise limit. Previous computational studies have investigated how the fluctuation of model adsorbate dipoles affects anomalous heating. However, the way in which specific adsorbates affect the electric field noise has not yet been examined, and an electric dipole model employed in previous studies is only accurate for a small subset of possible adsorbates. Here, we analyze the behavior of both in plane and out of plane vibrational modes of fifteen adsorbate electrode combinations within the independent fluctuating dipole model, utilizing accurate first principles computational methods to determine the surface induced dipole moments. We find the chemical specificity of the adsorbate can change the electric field noise by seven orders of magnitude and specifically that soft in plane modes of weakly adsorbed hydrocarbons produce the greatest noise and ion heating. We discuss the dynamics captured by the independent fluctuating dipole model, namely the adsorbate dependent turn on temperature and electric field noise magnitude, and also discuss the model's failure to reproduce the 1/\omega} frequency scaling observed in measured noise spectra. Finally, we suggest future research directions for improved, more quantitatively predictive models based on extensions of the present framework.
author_names: Keith G Ray

Brenda M Rubenstein

Wenze Gu

Vincenzo Lordi
title: van der Waals corrected density functional study of electric field noise heating in ion traps caused by electrode surface adsorbates
venue: New Journal of Physics
year: 2019