Theoretical model for ultracold molecule formation via adaptive feedback control

We investigate pump-dump photoassociation of ultracold molecules with amplitude- and phase-modulated femtosecond laser pulses. For this purpose a perturbative model for the light-matter interaction is developed and combined with a genetic algorithm for adaptive feedback control of the laser pulse shapes. The model is applied to the formation of 85Rb2 molecules in a magneto-optical trap. We find for optimized pulse shapes an improvement for the formation of ground state molecules by more than a factor of 10 compared to unshaped pulses at the same pump-dump delay time, and by 40% compared to unshaped pulses at the respective optimal pump-dump delay time. Since our model yields directly the spectral amplitudes and phases of the optimized pulses, the results are directly applicable in pulse shaping experiments

Suppression of power-broadening in strong-coupling photoassociation in the presence of a Feshbach resonance

Photoassociation (PA) spectrum in the presence of a magnetic Feshbach resonance is analyzed. Nonperturbative solution of the problem yields analytical expressions for PA linewidth and shift which are applicable for arbitrary PA laser intensity and magnetic field tuning of Feshbach Resonance. We show that by tuning magnetic field close to Fano minimum, it is possible to suppress power broadening at increased laser intensities. This occurs due to quantum interference of PA transitions from unperturbed and perturbed continuum. Line narrowing at high laser intensities is accompanied by large spectral shifts. We briefly discuss important consequences of line narrowing in cold collisions.Comment: 12 pages, 5 figure

Data triangulation in a user evaluation of the sealife semantic web browsers

There is a need for greater attention to triangulation of data in user-centred evaluation of Semantic Web Browsers. This paper discusses triangulation of data gathered during development of a novel framework for user-centred evaluation of Semantic Web Browsers. The data was triangulated from three sources: quantitative data from web server logs and questionnaire results, and qualitative data from semi-structured interviews. This paper shows how triangulation was essential in validation and completeness of the results, and was indispensable in ensuring accurate interpretation of the results in determining user satisfaction

The use of standards for identifying, codifying and transmitting expert ergonomic knowledge

Formal technical standards based on ergonomic principles can ensure that products, systems and services are fit for purpose, accessible and useable. The application of these standards should be used to ensure that items of technology meet political requirements for equality by enabling the full range of end users to participate in the digital society. Ergonomists and representatives of consumers participate in the specification and creation of these standards to ensure that their content is relevant, correct and up-to-date. They work to ensure that the standards accurately represent the needs and requirements of end users including amongst others people with disabilities, older people and people with different language and cultural backgrounds. A number of these standards are referenced in law and in procurement contracts. They are not often not used in higher education resulting in knowledge deficit for young technical professionals. The paper is based on the authors experience including working in the area of accessibility standardization and at a University which prides itself on the diversity of its staff and has students from more than 150 nations. The paper ends with a consideration of the way in which more effective use can be made of these standards

Cooling toolbox for atoms in optical lattices

We propose and analyze several schemes for cooling bosonic and fermionic atoms in an optical lattice potential close to the ground state of the no-tunnelling regime. Some of the protocols rely on the concept of algorithmic cooling, which combines occupation number filtering with ideas from ensemble quantum computation. We also design algorithms that create an ensemble of defect-free quantum registers. We study the efficiency of our protocols for realistic temperatures and in the presence of a harmonic confinement. We also propose an incoherent physical implementation of filtering which can be operated in a continuous way.Comment: 14 pages, 13 figure

Formation and interactions of cold and ultracold molecules: new challenges for interdisciplinary physics

Progress on researches in the field of molecules at cold and ultracold temperatures is reported in this review. It covers extensively the experimental methods to produce, detect and characterize cold and ultracold molecules including association of ultracold atoms, deceleration by external fields and kinematic cooling. Confinement of molecules in different kinds of traps is also discussed. The basic theoretical issues related to the knowledge of the molecular structure, the atom-molecule and molecule-molecule mutual interactions, and to their possible manipulation and control with external fields, are reviewed. A short discussion on the broad area of applications completes the review.Comment: to appear in Reports on Progress in Physic