Quantum dynamics of a resonator driven by a superconducting single-electron transistor: a solid-state analogue of the micromaser

We investigate the behavior of a quantum resonator coupled to a superconducting single-electron transistor (SSET) tuned to the Josephson quasiparticle resonance and show that the dynamics is similar in many ways to that found in a micromaser. Coupling to the SSET can drive the resonator into nonclassical states of self-sustained oscillation via either continuous or discontinuous transitions. Increasing the coupling further leads to a sequence of transitions and regions of multistability.     

An application of a transcorrelated procedure to the calculation of the energy of the hydrogen molecule

The ground-state energy of the hydrogen molecule is calculated using both the standard variational method and a new transcorrelated method. The value obtained with the new method compares favourably with that obtained by the standard method. If the method used in this paper can be extended to more complicated systems, it is expected that it will enable more accurate energies to be calculated for these systems than is possible using the standard variational method.     

Calculations of the Auger deexcitation rate of the dtμ within the muonic quasi-molecule, [(dtμ)dee]

A key process in muon catalysed fusion is the deexcitation of the dt within the resonant muonic quasi-molecule [(dt)dee], by emission of an Auger electron. The dt in the quasi-molecule is initially in a weakly bound excited state withJ=1 andv=1. In this paper, calculations taking full account of the molecular nature of the quasi-molecule are carried out of the rate of the dominant deexcitation to the state withJ=0 andv=1.     

Large scale manufacturing of compound semiconductors by MOVPE

As more compound semiconductor devices reach large volume manufacturing levels, a trend toward the use of the MOVPE technique is clear. In this paper we examine the criteria needed for MOVPE equipment suitable for large scale manufacturing. We find that although uniformity and device performance are necessary, reproducibility is also critical, along with high throughput and low operating costs. These points are illustrated by actual examples including MMIC power amplifiers, HB-LEDs, and solar cells. A realistic COO model provides a tool for evaluating MOVPE systems of different capacities. In situ control of key parameters during growth is now feasible, and will become an important method for increasing reproducibility and throughput. Lastly we look at the prospects for automation, for decreasing labor costs as well as wafer handling. This is likely to first have an impact on systems for the growth of electronic device structures on large (100 and 150 mm) wafers.     

Asymptotic form of three-body (dtµ)+ and (ddµ)+ wave functions

In order to investigate a discrepancy between existing literature values for the normalization constant in the asymptotic form of three-body wave functions for (dtµ)⁺, we report the results of a new calculation of the normalization constants for this system as well as the related system (ddµ)⁺. These were obtained by fitting to accurate variational wave functions with special care being taken to describe the long-range behavior.     

Low Temperature Hydrogen Antihydrogen Interactions

In view of current interest in the trapping of antihydrogen ( ) atoms at low temperatures [1–3], we have carried out a full four-body variational calculation to determine s-wave elastic phase shifts for hydrogen antihydrogen scattering, using the Kohn Variational Principle. Terms outside the Born–Oppenheimer approximation have been taken into account using the formalism of Kołos and Wolniewicz [4]. As far as we are aware, this is the first time that these terms have been included in an H scattering calculation. This is a continuation of earlier work on H– interactions [5–7]. Preliminary results differ substantially from those calculated using the Born–Oppenheimer approximation [8–10]. A method is outlined for reducing this discrepancy and taking the rearrangement channel into account. This revised version was published online in August 2006 with corrections to the Cover Date.