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

Hybridity in MT: experiments on the Europarl corpus

(Way & Gough, 2005) demonstrate that their Marker-based EBMT system is capable of outperforming a word-based SMT system trained on reasonably large data sets. (Groves & Way, 2005) take this a stage further and demonstrate that while the EBMT system also outperforms a phrase-based SMT (PBSMT) system, a hybrid 'example-based SMT' system incorporating marker chunks and SMT sub-sentential alignments is capable of outperforming both baseline translation models for French{English translation. In this paper, we show that similar gains are to be had from constructing a hybrid 'statistical EBMT' system capable of outperforming the baseline system of (Way & Gough, 2005). Using the Europarl (Koehn, 2005) training and test sets we show that this time around, although all 'hybrid' variants of the EBMT system fall short of the quality achieved by the baseline PBSMT system, merging elements of the marker-based and SMT data, as in (Groves & Way, 2005), to create a hybrid 'example-based SMT' system, outperforms the baseline SMT and EBMT systems from which it is derived. Furthermore, we provide further evidence in favour of hybrid systems by adding an SMT target language model to all EBMT system variants and demonstrate that this too has a positive e®ect on translation quality

An investigation of nuclear collisions with a momentum-dependent Lattice Hamiltonian model

We formulate a Lattice Hamiltonian approach for the modeling of intermediate energy heavy ion collisions. After verifying stationary ground state solutions, we implement this in a calculation of nuclear stopping power and compare our results with experimental data. Our findings support a relatively soft nuclear equation of state, with a momentum-dependent self-consistent mean field.Comment: 8 pages including 2 figures. MRST '99 conference proceedings, Carleton University, Ottawa, Canad

Supplement use in sport: is there a potentially dangerous incongruence between rationale and practice?

BACKGROUND: Supplement use by athletes is complex and research supports the alarming notion of misinformed decisions regarding supplements. HYPOTHESIS: A frequent divergence between the type of supplements chosen by athletes and the rationale dictating the supplement use is hypothesized. Thus, a potentially dangerous incongruence may exist between rationale and practice. TESTING THE HYPOTHESIS: In the continued absence of reliable data on supplement use, an alternative approach of studying the reasons underlying supplement use in athletes is proposed to determine whether there is an incongruence between rationale and practice. Existing data from large scale national surveys can be used to investigate this incongruence. IMPLICATIONS OF THE HYPOTHESIS: In this report, analyses of distinctive patterns between the use and rationale for use of supplements among athletes are recommended to explore this potentially dangerous phenomenon

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

Laboratory Development of a Passive Proportional Sampler for Overland FlowStudies in Agricultural Fields

peer-reviewedWater-quality in many rivers remains poor and needs to be improved. Diffuse pollution continues to cause difficulties. Some instruments are available which can monitor pollution of rivers from land. They allow measurement and sampling of overland flow (OLF), but they do not offer the precision required (proportional sampling and samples 0.1% of OLF). A laboratory unit was constructed to mimic instrument performance in the field. This was used to test three sampler designs. A V-notch weir was used in the first sampler and a Sutro weir in the second and third as this unit possessed a proportional discharge to head ratio, which the Vnotch weir did not have. Other parameters investigated included ground slope, sampler slope, pipe size and port location. The remaining issues of nozzle size (0.7, 1.0 and 2.0 mm), the number of 1.0 mm nozzles and the effect of aspiration were investigated. The arrangement with the Sutro weir and three 1.0 mm nozzles in series gave proportional discharge and the target low sampling rate of 0.1%. This will allow the calculation of sediment and chemical losses for the monitored area and will put the loss in context with other losses in a catchment

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

Taking the temperature – forecasting GDP growth for mainland China

We present a new composite leading indicator of economic activity in mainland China, es-timated using a dynamic factor model. Our leading indicator is constructed from three se-ries: exports, a real estate climate index, and the Shanghai Stock Exchange index. These series are found to share a common, unobservable element from which our indicator can be identified. This indicator is then incorporated into out-of-sample one-step-ahead forecasts of Chinese GDP growth. Recursive out-of-sample accuracy tests indicate that the small-scale factor model approach leads to a successful representation of the sample data and provides an appropriate tool for forecasting Chinese business conditions.forecasting; China; leading indicator; factor model; growth cycles

"The Roles of Interaction and Proximity for Innovation by Irish High-Technology Businesses: Policy Implications"

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