Enhancement of entanglement in one-dimensional disordered systems

The pairwise quantum entanglement of sites in disordered electronic one-dimensional systems (rings) is studied. We focus on the effect of diagonal and off diagonal disorder on the concurrence $C_{ij}$ between electrons on neighbor and non neighbor sites $i,j$ as a function of band filling. In the case of diagonal disorder, increasing the degree of disorder leads to a decrease of the concurrence with respect to the ordered case. However, off-diagonal disorder produces a surprisingly strong enhancement of entanglement. This remarkable effect occurs near half filling, where the concurrence becomes up to 15% larger than in the ordered system.Comment: 21 pages, 9 figure

Collective Social Capital Within a Performance-Based Management System

Local education agencies utilizing performance-based management systems as a means to improve educator effectiveness and student performance is becoming more prevalent within the United States. High-need schools are implementing these systems and endeavor to create an environment that promotes a professional learning community that improves educator quality and student achievement. This study seeks to measure the level of collective social capital generated by the implementation of one such management system, Rewarding Excellence in Instruction and Leadership, through the use of a sociological case study. Through the use of document analysis and interviews, the degree of collective social capital fostered will be sought to better understand the potential for impacting educator effectiveness

Spectral broadening of frequency combs via pulse apodization prior to nonlinear propagation

This thesis focuses on specific methods for spectrally broadening large repetition rate frequency combs using the idea that tailoring the shape of the seed pulse prior to nonlinear propagation will result in a spectrally flatter comb. A spectrally flat comb is desired for applications in optical communications, arbitrary waveform generation, and microwave photonic filtering. Three experimental setups using Fourier transform pulse shapers, Dispersion Decreasing Fiber (DDF) or Highly Nonlinear Fiber (HNLF) as the nonlinear propagation media were performed. Simulations employing the Split Step Fourier Method to solve the Nonlinear Schrödinger Equation were performed to analyze the experimental results. The first experiments employed DDF to produce a compressed pulse via Adiabatic Soliton Compression. This pulse was launched into the second stage and HNLF broadened the comb spectrum via Self Phase Modulation. A promising 130nm broadened comb spectrum was returned. The next experiments showed that, by apodizing the pulse produced by the optoelectronic frequency comb generator prior to propagation in HNLF, a flatter broadened comb spectrum was returned. These results were extended to a two-stage setup. The setup used two stages of HNLF. Sech apodization in the first stage and parabolic apodization in the second stage led to promising simulation results. With the insight gained by the simulations, experiments were performed and a flat broadened frequency comb led to applications in RF photonic filtering. An RF photonic phase filter was implemented with the comb generated as the source, and pulse compression experiments were performed

Characterization of the C. elegans nascent polypeptide associated complex (NAC) function under stress

The nascent polypeptide-associated complex (NAC) is a highly conserved heterodimer known to play an important role in protein folding and localization during metazoan development. Evidence in different model systems indicates that removal of either subunit of the NAC, i.e. α- or β-NAC, is sufficient to generate misfolded protein stress in the endoplasmic reticulum (ER), resulting in the activation of the ER-specific unfolded protein response (UPR). What is not yet understood is the nature of the UPR depending on which subunit of the NAC is depleted. My research is focused on characterizing the specific UPR outcomes induced upon depletion of either α- or β-NAC during misfolded protein stress in the ER. Assessment of UPR outcomes revealed that depletion of the C. elegans NAC homologues icd-1/NAC and icd-2/NAC shared unique responses relative to the subunit depleted. Specifically, depletion of ICD-1 led to increased ER specific chaperone expression and robust attenuation of protein synthesis when compared to depletion of ICD-2. Along with managing protein homeostasis during ER stress, I also found that specific components of the NAC and UPR actively contribute to cell differentiation programs, e.g. embryos depleted of ICD-1 displayed altered neuronal marker expression during ER stress, while other cell-type specific markers remained unchanged. These results suggest the individual subunits of the C. elegans NAC are functional when unbound and contribute differentially to the activation of the UPR when one subunit is in excess relative to the other. Such findings may provide insights into the pathology of diseases such as Alzheimer’s, in which the 1:1 stoichiometry of the NAC subunits is disrupted

Covariant Impulse Approximation for the study of the internal structure of composite particles

We present a brief review on the Impulse Approximation method to study processes of scattering off composite particles. We first construct the model in a non-relativistic fashion that enables us to extend the model to a covariant Impulse Approximation, which is needed for the study of high momentum transfer processes.Comment: 8 Page