Anomalous strong exchange narrowing in excitonic systems

We investigate theoretically the phenomenon of exchange narrowing in the absorption spectrum of a chain of monomers, which are coupled via resonant dipole-dipole interaction. The individual (uncoupled) monomers exhibit a broad absorption line shape due to the coupling to an environment consisting of a continuum of vibrational modes. Upon increasing the interaction between the monomers, the absorption spectrum of the chain narrows. For a non-Markovian environment with a Lorentzian spectral density, we find a narrowing of the peak width (full width at half maximum (FWHM)) by a factor 1/N, where N is the number of monomers. This is much stronger than the usual 1/sqrt{N} narrowing. Furthermore it turns out that for a Markovian environment no exchange narrowing at all occurs. The relation of different measures of the width (FWHM, standard deviation) is discussed

A probability current analysis of energy transport in open quantum systems

We introduce a probability current analysis of excitation energy transfer between states of an open quantum system. Expressing the energy transfer through currents of excitation probability between the states in a site representation enables us to gain key insights into the energy transfer dynamics. It allows to, i) identify the pathways of energy transport in large networks of sites and to quantify their relative weights, ii) quantify the respective contributions of unitary dynamics, dephasing, and relaxation/dissipation processes to the energy transfer, and iii) quantify the contribution of coherence to the energy transfer. Our analysis is general and can be applied to a broad range of open quantum system descriptions (with coupling to non-Markovian environments) in a straightforward manner

Continuous Measurement of a Non-Markovian Open Quantum System

Continuous quantum measurement is the backbone of various methods in quantum control, quantum metrology, and quantum information. Here, we present a generalized formulation of dispersive measurement of a complex quantum systems. We describe the complex system as an open quantum system that is strongly coupled to a non-Markovian environment, enabling the treatment of a broad variety of natural or engineered complex systems. The system is monitored via a probe resonator coupled to a broadband (Markovian) reservoir. Based on this model, we derive a formalism of Stochastic Hierarchy Equations of Motion (SHEM) describing the decoherence dynamics of the system conditioned on the measurement record. Furthermore, we demonstrate a spectroscopy method based on weak quantum measurement to reveal the non-Markovian nature of the environment, which we term weak spectroscopy.Comment: Published version, the section on continuous state tomography will be published in a separate manuscrip

Comparative experiences of two teacher educators: a self study

This paper focuses on the reflections of a less experienced and a veteran teacher educator at a new university and compares and contrasts their experiences of primary teacher education. The paper draws on the power of the narrative to share these experiences through aspects of self-study. Autobiographical research methods were used to elicit reflection on significant events in the teacher educators’ different and individual pasts in order to understand more about effective learning and teaching in their present roles. This process led to an examination of the values that underpinned and continue to underpin practice. The collaborative examination of significant aspects of personal practice has led to renewed confidence and implications for primary teacher education within the University

A study of the distribution of selected anthropogenic micropollutants in the seawater of Dublin bay

Since the middle of the last century there has been a growing awareness of the existence of widespread environmental pollution and of the potentially harmful effects that polluting species can have on biological systems. Initially the concern focused on the ubiquity and on the harmful effects of organochlorine compounds, in particular organochlorine pesticides. In the 1970s the malign effect that xeno-estrogenic material could have on biological systems became apparent and the increasing incidence of such polluting material, frequently derived from sewage or other wastewater effluent, in the aquatic environment provoked concern. A more recent topic for research has been the occurrence in the aquatic environment of the residues of pharmaceuticals originally developed and prescribed for the treatment of human or animal illnesses or physiological complaints. Though ample evidence has been recorded for the prevalence of such residues no definite conclusions have been reached regarding the effects of such pollution. This work targeted six compounds that were deemed to have potential for anthropogenic pollution. The species selected were caffeine, methylparaben, estradiol, ethynylestradiol, ibuprofen and nonylphenol. Dublin bay was chosen as a sampling site. HPLC methods for the identification and the quantification of each of these compounds were developed. The method for the detection of caffeine had a limit of detection (LOD) of 0.005 mgL-1 and a limit of quantification (LOQ) of 0.02 mgL-1. The method for estradiol, which utilised the natural fluorescence of this compound as a means of detection, had a LOD of 0.0025 mgL-1 and a LOQ of 0.05 mgL-1. A solid phase extraction method for the extraction of these compounds from seawater was established. This method had a recovery rate of 83.2% for caffeine and 88.9% for estradiol. Items of glassware that would allow the siinultaneous preparation of up to 12 extracts of seawater that would be suitable for HPLC analysis were designed

Spectral properties of molecular oligomers. A non-Markovian quantum state diffusion approach

Absorption spectra of small molecular aggregates (oligomers) are considered. The dipole-dipole interaction between the monomers leads to shifts of the oligomer spectra with respect to the monomer absorption. The line-shapes of monomer as well as oligomer absorption depend strongly on the coupling to vibrational modes. Using a recently developed approach [Roden et. al, PRL 103, 058301] we investigate the length dependence of spectra of one-dimensional aggregates for various values of the interaction strength between the monomers. It is demonstrated, that the present approach is well suited to describe the occurrence of the J- and H-bands

Using machine learning techniques to automate sky survey catalog generation

We describe the application of machine classification techniques to the development of an automated tool for the reduction of a large scientific data set. The 2nd Palomar Observatory Sky Survey provides comprehensive photographic coverage of the northern celestial hemisphere. The photographic plates are being digitized into images containing on the order of 10(exp 7) galaxies and 10(exp 8) stars. Since the size of this data set precludes manual analysis and classification of objects, our approach is to develop a software system which integrates independently developed techniques for image processing and data classification. Image processing routines are applied to identify and measure features of sky objects. Selected features are used to determine the classification of each object. GID3* and O-BTree, two inductive learning techniques, are used to automatically learn classification decision trees from examples. We describe the techniques used, the details of our specific application, and the initial encouraging results which indicate that our approach is well-suited to the problem. The benefits of the approach are increased data reduction throughput, consistency of classification, and the automated derivation of classification rules that will form an objective, examinable basis for classifying sky objects. Furthermore, astronomers will be freed from the tedium of an intensely visual task to pursue more challenging analysis and interpretation problems given automatically cataloged data

When The Springtime Brings The Roses, Jessie Dear

https://digitalcommons.library.umaine.edu/mmb-vp/5058/thumbnail.jp

When A Boy From Old New Hampshire Loves A Girl From Tennessee

https://digitalcommons.library.umaine.edu/mmb-vp/2710/thumbnail.jp