Quantum interface between an electrical circuit and a single atom

We show how to bridge the divide between atomic systems and electronic devices by engineering a coupling between the motion of a single ion and the quantized electric field of a resonant circuit. Our method can be used to couple the internal state of an ion to the quantized circuit with the same speed as the internal-state coupling between two ions. All the well-known quantum information protocols linking ion internal and motional states can be converted to protocols between circuit photons and ion internal states. Our results enable quantum interfaces between solid state qubits, atomic qubits, and light, and lay the groundwork for a direct quantum connection between electrical and atomic metrology standards.Comment: Supplemental material available on reques

Relating Green's Functions in Axial and Lorentz Gauges using Finite Field-Dependent BRS Transformations

We use finite field-dependent BRS transformations (FFBRS) to connect the Green functions in a set of two otherwise unrelated gauge choices. We choose the Lorentz and the axial gauges as examples. We show how the Green functions in axial gauge can be written as a series in terms of those in Lorentz gauges. Our method also applies to operator Green's functions. We show that this process involves another set of related FFBRS transfomations that is derivable from infinitesimal FBRS. We suggest possible applications.Comment: 20 pages, LaTex, Section 4 expanded, typos corrected; last 2 references modified; (this) revised version to appear in J. Math. Phy

Electron impact ionization loading of a surface electrode ion trap

We demonstrate a method for loading surface electrode ion traps by electron impact ionization. The method relies on the property of surface electrode geometries that the trap depth can be increased at the cost of more micromotion. By introducing a buffer gas, we can counteract the rf heating assocated with the micromotion and benefit from the larger trap depth. After an initial loading of the trap, standard compensation techniques can be used to cancel the stray fields resulting from charged dielectric and allow for the loading of the trap at ultra-high vacuum.Comment: 4 pages, 5 eps figures. Shift in focus, minor correction

Sympathetic Cooling of Mixed Species Two-Ion Crystals for Precision Spectroscopy

Sympathetic cooling of trapped ions has become an indispensable tool for quantum information processing and precision spectroscopy. In the simplest situation a single Doppler-cooled ion sympathetically cools another ion which typically has a different mass. We analytically investigate the effect of the mass ratio of such an ion crystal on the achievable temperature limit in the presence of external heating. As an example, we show that cooling of a single Al+ with Be+, Mg+ and Ca+ ions provides similar results for heating rates typically observed in ion traps, whereas cooling ions with a larger mass perform worse. Furthermore, we present numerical simulation results of the rethermalisation dynamics after a background gas collision for the Al+/Ca+ crystal for different cooling laser configurations.Comment: Made Graphics black & white print compatible, clarified abstract and summar

Rolling-joint design optimization for tendon driven snake-like surgical robots

The use of snake-like robots for surgery is a popular choice for intra-luminal procedures. In practice, the requirements for strength, flexibility and accuracy are difficult to be satisfied simultaneously. This paper presents a computational approach for optimizing the design of a snake-like robot using serial rolling-joints and tendons as the base architecture. The method optimizes the design in terms of joint angle range and tendon placement to prevent the tendons and joints from colliding during bending motion. The resulting optimized joints were manufactured using 3D printing. The robot was characterized in terms of workspace, dexterity, precision and manipulation forces. The results show a repeatability as low as 0.9mm and manipulation forces of up to 5.6N

Cryogenic Ion Trapping Systems with Surface-Electrode Traps

We present two simple cryogenic RF ion trap systems in which cryogenic temperatures and ultra high vacuum pressures can be reached in as little as 12 hours. The ion traps are operated either in a liquid helium bath cryostat or in a low vibration closed cycle cryostat. The fast turn around time and availability of buffer gas cooling made the systems ideal for testing surface-electrode ion traps. The vibration amplitude of the closed cycled cryostat was found to be below 106 nm. We evaluated the systems by loading surface-electrode ion traps with $^{88}$Sr$^+$ ions using laser ablation, which is compatible with the cryogenic environment. Using Doppler cooling we observed small ion crystals in which optically resolved ions have a trapped lifetime over 2500 minutes.Comment: 10 pages, 13 EPS figure

Making the leap: the translation of innovative surgical devices from the laboratory to the operating room

MINI-ABSTRACT: A decade from publication, approximately one in ten surgical devices described in the literature made the leap from the laboratory to a first-in-human study. Clinical involvement was a significant predictor of translation; devices developed with clinical collaboration were over six times more likely to be translated than those without. STRUCTURED ABSTRACT: OBJECTIVE: To determine the rate and extent of translation of innovative surgical devices from the laboratory to first-in-human studies, and to evaluate the factors influencing such translation. SUMMARY BACKGROUND DATA: Innovative surgical devices have preceded many of the major advances in surgical practice. However, the process by which devices arising from academia find their way to translation remains poorly understood. METHODS: All biomedical engineering journals, and the five basic science journals with the highest impact factor, were searched between January 1993 and January 2000 using the Boolean search term “surgery OR surgeon OR surgical”. Articles were included if they described the development of a new device and a surgical application was described. A recursive search of all citations to the article was performed using the Web of Science (Thompson-Reuters, New York, USA) to identify any associated first-in-human studies published by January 2015. Kaplan-Meier curves were constructed for the time first-in-human studies. Factors influencing translation were evaluated using Log Rank and Cox proportional hazards models. RESULTS: 8,297 articles were screened, and 205 publications describing unique devices identified. The probability of a first-in-human at 10 years was 9.8%. Clinical involvement was a significant predictor of a first-in-human study (p = 0.02); devices developed with early clinical collaboration were over six times more likely to be translated than those without (RR 6.5 [95% CI 0.9 - 48]). CONCLUSIONS: These findings support initiatives to increase clinical translation through improved interactions between basic, translational, and clinical researchers

A surface electrode point Paul trap

We present a model as well as experimental results for a surface electrode radio-frequency Paul trap that has a circular electrode geometry well-suited for trapping of single ions and two-dimensional planar ion crystals. The trap design is compatible with microfabrication and offers a simple method by which the height of the trapped ions above the surface may be changed \emph{in situ}. We demonstrate trapping of single and few Sr+ ions over an ion height range of 200-1000 microns for several hours under Doppler laser cooling, and use these to characterize the trap, finding good agreement with our model.Comment: 10 pages, 11 figures, 1 tabl

Quantum gate in the decoherence-free subspace of trapped ion qubits

We propose a geometric phase gate in a decoherence-free subspace with trapped ions. The quantum information is encoded in the Zeeman sublevels of the ground-state and two physical qubits to make up one logical qubit with ultra long coherence time. Single- and two-qubit operations together with the transport and splitting of linear ion crystals allow for a robust and decoherence-free scalable quantum processor. For the ease of the phase gate realization we employ one Raman laser field on four ions simultaneously, i.e. no tight focus for addressing. The decoherence-free subspace is left neither during gate operations nor during the transport of quantum information.Comment: 6 pages, 6 figure

Experimental investigation of planar ion traps

Chiaverini et al. [Quant. 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 0.44 micron diameter charged particles in a vacuum of 15 Pa (0.1 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 novel planar ion trap geometry that generates a two dimensional lattice of point Paul traps.Comment: 11 pages, 20 figure