Open quantum systems and Random Matrix Theory

A simple model for open quantum systems is analyzed with Random Matrix Theory. The system is coupled to the continuum in a minimal way. In this paper we see the effect of opening the system on the level statistics, in particular the $\Delta_3(L)$ statistic, width distribution and level spacing are examined as a function of the strength of this coupling. A super-radiant transition is observed, and it is seen that as it is formed, the level spacing and $\Delta_3(L)$ statistic exhibit the signatures of missed levels.Comment: 15 pages, 9 figure

A maximum likelihood method to correct for missed levels based on the Δ3(L)\Delta_3(L) statistic

The $\Delta_3(L)$ statistic of Random Matrix Theory is defined as the average of a set of random numbers $\{\delta\}$, derived from a spectrum. The distribution $p(\delta)$ of these random numbers is used as the basis of a maximum likelihood method to gauge the fraction $x$ of levels missed in an experimental spectrum. The method is tested on an ensemble of depleted spectra from the gaussian orthogonal ensemble (GOE), and accurately returned the correct fraction of missed levels. Neutron resonance data and acoustic spectra of an aluminum block were analyzed. All results were compared with an analysis based on an established expression for $\Delta_3(L)$ for a depleted GOE spectrum. The effects of intruder levels is examined, and seen to be very similar to that of missed levels. Shell model spectra were seen to give the same $p(\delta)$ as the GOE.Comment: 23 pages, 13 figures, 1 tabl

Moore's Paradox and the Accessibility of Justification

This paper argues that justification is accessible in the sense that one has justification to believe a proposition if and only if one has higher-order justification to believe that one has justification to believe that proposition. I argue that the accessibility of justification is required for explaining what is wrong with believing Moorean conjunctions of the form, ‘p and I do not have justification to believe that p.

On Pain of Death

On Pain of Death is a fictional retelling of the story of Sir Pelleas, who, in Thomas Malory’s Le Morte D’Arthur, is depicted as a noble knight with unrequited love for Lady Ettarde. He follows her for weeks, repeatedly declaring his love for her, despite her clear rejections. In rewriting this story, I hope to draw attention to the fact that, by today’s standards, what he is doing is clear-cut stalking. By introducing a character with a periphery perspective, I hope to call into question how “romantic” these stories of unrequited love really are

A Capital Mistake? The Neglected Effect of Immigration on Average Wages

Much recent literature on the wage effects of immigration assumes that the return to capital, and therefore the average wage, is unaffected in the long run. If immigration is modelled as a continuous flow rather than a one off shock, this result does not necessarily hold. A simple calibration with pre-crisis US immigration rates gives a reduction in average wages of 5%, larger than most estimates of its effect on relative wages.

Hybrid example-based SMT: the best of both worlds?

(Way and Gough, 2005) provide an indepth comparison of their Example-Based Machine Translation (EBMT) system with a Statistical Machine Translation (SMT) system constructed from freely available tools. According to a wide variety of automatic evaluation metrics, they demonstrated that their EBMT system outperformed the SMT system by a factor of two to one. Nevertheless, they did not test their EBMT system against a phrase-based SMT system. Obtaining their training and test data for English–French, we carry out a number of experiments using the Pharaoh SMT Decoder. While better results are seen when Pharaoh is seeded with Giza++ word- and phrase-based data compared to EBMT sub-sentential alignments, in general better results are obtained when combinations of this 'hybrid' data is used to construct the translation and probability models. While for the most part the EBMT system of (Gough & Way, 2004b) outperforms any flavour of the phrasebased SMT systems constructed in our experiments, combining the data sets automatically induced by both Giza++ and their EBMT system leads to a hybrid system which improves on the EBMT system per se for French–English

A Risk Assessment and Hazard Analysis and Critical Control Point (HACCP) Study for the Irish Catering Industry

End of project reportThis report provides details of a food safety knowledge survey, a microbiological survey, a chilled temperature survey and an audit conducted in 200 restaurants throughout the island of Ireland. The results suggest a low incidence of several bacterial pathogens (including Salmonella enterica) and identify areas in which food safety knowledge, procedures and practices should be improved. Salmonella enterica isolates were characterised and the results suggested distinct pockets of different serotypes. Growth curves for L. monocytogenes isolates suggest considerably reduced shelf-life for a variety of foods. For example, lettuce should not be stored at room temperature or the shelf-life is reduced from 6.5 days (chilled storage) to 3.3 days.The predicted shelf-life for fresh milk was 4.5 days (chilled storage). Chlorine (sodium hypochlorite, 5 ppm), 1-monolauroyl-rac-glycerol and a laurate ester (ester-glucoside laurate) were also tested for application as vegetable decontaminating agents in restaurant kitchens. The report concludes with recommendations for improved food safety and hygiene in Irish restaurants.Safefoo

Scale-lengths and instabilities in magnetized classical and relativistic plasma fluid models

The validity of the traditional plasma continuum is predicated on a hierarchy of scale-lengths, with the Debye length being considered to be effectively unresolvable in the continuum limit. In this article, we revisit the strong magnetic field case in which the Larmor radius is comparable or smaller than the Debye length in the classical plasma, and also for a relativistic plasma. Fresh insight into the validity of the continuum assumption in each case is offered, including a fluid limit on the Alfven speed that may impose restrictions on the validity of MHD in some solar and fusion contexts. Additional implications concerning the role of the firehose instability are also explored