Using ultra-thin parylene films as an organic gate insulator in nanowire field-effect transistors

We report the development of nanowire field-effect transistors featuring an ultra-thin parylene film as a polymer gate insulator. The room temperature, gas-phase deposition of parylene is an attractive alternative to oxide insulators prepared at high temperatures using atomic layer deposition. We discuss our custom-built parylene deposition system, which is designed for reliable and controlled deposition of <100 nm thick parylene films on III-V nanowires standing vertically on a growth substrate or horizontally on a device substrate. The former case gives conformally-coated nanowires, which we used to produce functional $\Omega$-gate and gate-all-around structures. These give sub-threshold swings as low as 140 mV/dec and on/off ratios exceeding $10^3$ at room temperature. For the gate-all-around structure, we developed a novel fabrication strategy that overcomes some of the limitations with previous lateral wrap-gate nanowire transistors. Finally, we show that parylene can be deposited over chemically-treated nanowire surfaces; a feature generally not possible with oxides produced by atomic layer deposition due to the surface `self-cleaning' effect. Our results highlight the potential for parylene as an alternative ultra-thin insulator in nanoscale electronic devices more broadly, with potential applications extending into nanobioelectronics due to parylene's well-established biocompatible properties

ECOSYSTEM APPROACH TO FISHERIES MANAGEMENT IN THE SOUTHERN BENGUELA: A WORKSHOP OVERVIEW

A workshop was held in Cape Town in December 2002 to introduce the concept of an ecosystem approach to fisheries (EAF) management in the southern Benguela, and to examine the options for implementing an EAF in South Africa. The workshop considered alternative modelling approaches that may have potential for an ecosystem approach to fisheries. Consensus was that an EAF should be implemented in South Africa through an incremental process, starting immediately. Ecosystem models can be used to provide guidance on reference points and broader management objectives still currently set on the basis of single-species assessments. Such additional information would be incorporated into the decision-making process, and comments received at a management level would also feed back to the modelling process. It was suggested that, at the scientific level, an ecosystem modelling perspective could be incorporated into existing single-species management recommendations by testing them with ecosystem models. Compilation of an “ecosystem considerations” document was recommended to initiate the process. It was proposed that a dedicated EAF working group be established in South Africa to advise on the process of implementing an EAF in the various fisheries, and to provide overarching guidance and to ensure consistency in integrating existing data and information for informing the management process

Maximal entanglement of squeezed vacuum states via swapping with number-phase measurement

We propose a method to refine entanglement via swapping from a pair of squeezed vacuum states by performing the Bell measurement of number sum and phase difference. The resultant states are maximally entangled by adjusting the two squeezing parameters to the same value. We then describe the teleportation of number states by using the entangled states prepared in this way.Comment: 4 pages, 1 PS figure, RevTe

Using the trajectory of the shuttlecock as a measure of performance accuracy in the badminton short serve

Accuracy of a projectile is typically quantified as the proportion of successful target hits, or the distance an object finishes from the target. Serving in sports such as badminton differs since the shuttlecock is usually intercepted by the opponent before landing on the target (i.e. court surface). Therefore, landing accuracy measures are inappropriate and a new method of determining accuracy of the serve is needed. During interviews, elite coaches and players described an accurate short serve as crossing the net with low clearance and having an apex before the net. Three-dimensional trajectory of the shuttlecock was therefore tracked from eight national-level players who performed 30 short serves in simulated match conditions (i.e. with an opponent); 27% of all serves were classified as ‘accurate’, 27% of serves as ‘inaccurate’, 21% with a ‘good apex’ position, and 25% with a ‘good clearance’ height. The proposed method of assessing shuttlecock trajectory as a measure of accuracy could be adopted by coaches and players to assess and improve short serve accuracy. Furthermore, this method is more representative of a match environment since the shuttlecock rarely lands because the opponent returns the serve

A multicentre integration of a computer-led follow-up of prostate cancer is valid and safe

Background Prostate cancer (CaP) has a rising number of patients requiring routine follow up. In this study, we aimed to test a computer led follow up service for prostate cancer in two UK hospitals. The testing aimed to validate the computer Expert system in making clinical decisions according to the individual patient’s clinical need. The valid model should accurately identify patients with disease recurrence or treatment failure based on their blood test and clinical picture. Methods A clinical decision support system (CDSS) was developed from European (EAU) and national (NICE) guidelines along with knowledge acquired from Urologists. This model was then applied in two UK hospitals to review patients post CaP treatment. These patients’ data (n= 200) were then reviewed by two independent Urology consultants (blinded from the CDSS and other consultant’s rating) and the agreement was calculated by kappa statistics for validation. The second objective aimed to verify the system by estimating the system reliability. Results The two individual urology consultants identified 12 % & 15% of the patients to have potential disease progression and recommended their referral to the Urology care. The kappa coefficient for the agreement between the CDSS and the 2 consultants was 0.81 (p < 0.001) and 0.84 (p < 0.001). The agreement among both specialist was also high with k = 0.83 (p < 0.001). The system reliability was estimated on all cases and this demonstrated 100% repeatability of the decisions. Conclusion The computer led follow up is a valid model for providing safe follow up for prostate cancer

Macroscopically distinct quantum superposition states as a bosonic code for amplitude damping

We show how macroscopically distinct quantum superposition states (Schroedinger cat states) may be used as logical qubit encodings for the correction of spontaneous emission errors. Spontaneous emission causes a bit flip error which is easily corrected by a standard error correction circuit. The method works arbitrarily well as the distance between the amplitudes of the superposed coherent states increases.Comment: 4 pages, 2 postscript figures, LaTeX2e, RevTeX, minor changes, 1 reference adde

Teleportation-based number state manipulation with number sum measurement

We examine various manipulations of photon number states which can be implemented by teleportation technique with number sum measurement. The preparations of the Einstein-Podolsky-Rosen resources as well as the number sum measurement resulting in projection to certain Bell state may be done conditionally with linear optical elements, i.e., beam splitters, phase shifters and zero-one-photon detectors. Squeezed vacuum states are used as primary entanglement resource, while single-photon sources are not required.Comment: 9 pages, 4 figures, Misprints are corrected. 3 figures for number sum measurement are added. Discussion on manipulations are expanded. Calculations for success probabilities are added. Fig.4 is adde

Beyond-adiabatic Quantum Admittance of a Semiconductor Quantum Dot at High Frequencies: Rethinking Reflectometry as Polaron Dynamics

Semiconductor quantum dots operated dynamically are the basis of many quantum technologies such as quantum sensors and computers. Hence, modelling their electrical properties at microwave frequencies becomes essential to simulate their performance in larger electronic circuits. Here, we develop a self-consistent quantum master equation formalism to obtain the admittance of a quantum dot tunnel-coupled to a charge reservoir under the effect of a coherent photon bath. We find a general expression for the admittance that captures the well-known semiclassical (thermal) limit, along with the transition to lifetime and power broadening regimes due to the increased coupling to the reservoir and amplitude of the photonic drive, respectively. Furthermore, we describe two new photon-mediated regimes Floquet broadening, determined by the dressing of the QD states, and broadening determined by photon loss in the system. Our results provide a method to simulate the high-frequency behaviour of QDs in a wide range of limits, describe past experiments, and propose novel explorations of QD-photon interactions

Conditional quantum-state transformation at a beam splitter

Using conditional measurement on a beam splitter, we study the transformation of the quantum state of the signal mode within the concept of two-port non-unitary transformation. Allowing for arbitrary quantum states of both the input reference mode and the output reference mode on which the measurement is performed, we show that the non-unitary transformation operator can be given as an $s$-ordered operator product, where the value of $s$ is entirely determined by the absolute value of the beam splitter reflectance (or transmittance). The formalism generalizes previously obtained results that can be recovered by simple specification of the non-unitary transformation operator. As an application, we consider the generation of Schr\"odinger-cat-like states. An extension to mixed states and imperfect detection is outlined.Comment: 7 Postscript figures, using Late