591 research outputs found
Hike Your Own Hike: Cosmopolitanism and Applied Behavior Analysis Explored Through SPN
Ever since I started working with animals, I felt an intrinsic motivation to develop relationships based on trust and mutual admiration. Working in the horse world, I became dismayed at the coercive methods used to assure progress and achieve competition goals. I moved to Burlington to pursue a career helping children. Working as a behavior interventionist I felt peace and satisfaction as I utilized my previous skills and knowledge learned from my work with animals and my undergraduate education. After about a year of work, I started to become frustrated and dismayed at the treatment of some of our children. This SPN thesis is an exploration of those challenges and who I wish to become as I move forward in my career
Information-theoretic measures of superconductivity in a two-dimensional doped Mott insulator
A key open issue in condensed matter physics is how quantum and classical
correlations emerge in an unconventional superconductor from the underlying
normal state. We study this problem in a doped Mott insulator with information
theory tools on the two-dimensional Hubbard model at finite temperature with
cluster dynamical mean-field theory. We find that the local entropy detects the
superconducting state and that the difference in the local entropy between the
superconducting and normal states follows the same difference in the potential
energy. We find that the thermodynamic entropy is suppressed in the
superconducting state and monotonically decreases with decreasing doping. The
maximum in entropy found in the normal state above the overdoped region of the
superconducting dome is obliterated by superconductivity. The total mutual
information, which quantifies quantum and classical correlations, is amplified
in the superconducting state of the doped Mott insulator for all doping levels,
and shows a broad peak versus doping, as a result of competing quantum and
classical effects.Comment: 8 pages, 4 figures, and supplementary information; accepted versio
Specific heat maximum as a signature of Mott physics in the two-dimensional Hubbard model
Recent experiments on cuprates show that as a function of doping, the
normal-state specific heat sharply peaks at the doping , where the
pseudogap ends at low temperature. This finding is taken as the thermodynamic
signature of a quantum critical point, whose nature has not yet been
identified. Here we present calculations for the two-dimensional Hubbard model
in the doped Mott insulator regime, which indicate that the specific heat
anomaly can arise from the finite temperature critical endpoint of a
first-order transition between a pseudogap phase with dominant singlet
correlations and a metal. As a function of doping at the temperature of the
endpoint, the specific heat diverges. Upon increasing temperature, the peak
becomes broader. The diverging correlation length is associated with uniform
density fluctuations. No broken symmetries are needed. These anomalies also
occur at half-filling as a function of interaction strength, and are relevant
for organic superconductors and ultracold atoms.Comment: 6 pages, 3 figures; published versio
Critical opalescence across the doping driven Mott transition in optical lattices of ultracold atoms
Phase transitions and their associated crossovers are imprinted in the
behavior of fluctuations. Motivated by recent experiments on ultracold atoms in
optical lattices, we compute the thermodynamic density fluctuations of the two-dimensional fermionic Hubbard model with plaquette cellular
dynamical mean-field theory. To understand the length scale of these
fluctuations, we separate the local from the nonlocal contributions to . We determine the effects of particle statistics, interaction strength
, temperature and density . At high temperature, our theoretical
framework reproduces the experimental observations in the doping-driven
crossover regime between metal and Mott insulator. At low temperature, there is
an increase of thermodynamic density fluctuations, analog to critical
opalescence, accompanied by a surprising reduction of the absolute value of
their nonlocal contributions. This is a precursory sign of an underlying phase
transition between a pseudogap phase and a metallic phase in doped Mott
insulators, which should play an important role in the cuprate high-temperature
superconductors. Predictions for ultracold atom experiments are made.Comment: 10 pages, 4 figures; published versio
An Experimental Field Study of Delayed Density Dependence in Natural Populations of Aedes albopictus
Aedes albopictus, a species known to transmit dengue and chikungunya viruses, is primarily a container-inhabiting mosquito. The potential for pathogen transmission by Ae. albopictus has increased our need to understand its ecology and population dynamics. Two parameters that we know little about are the impact of direct density-dependence and delayed density-dependence in the larval stage. The present study uses a manipulative experimental design, under field conditions, to understand the impact of delayed density dependence in a natural population of Ae. albopictus in Raleigh, North Carolina. Twenty liter buckets, divided in half prior to experimentation, placed in the field accumulated rainwater and detritus, providing oviposition and larval production sites for natural populations of Ae. albopictus. Two treatments, a larvae present and larvae absent treatment, were produced in each bucket. After five weeks all larvae were removed from both treatments and the buckets were covered with fine mesh cloth. Equal numbers of first instars were added to both treatments in every bucket. Pupae were collected daily and adults were frozen as they emerged. We found a significant impact of delayed density-dependence on larval survival, development time and adult body size in containers with high larval densities. Our results indicate that delayed density-dependence will have negative impacts on the mosquito population when larval densities are high enough to deplete accessible nutrients faster than the rate of natural food accumulation
The Grizzly, February 18, 2010
Every Ending Starts with a Beginning • Record-Breaking Blizzard Evokes Varied Reactions • Could Watching the Super Bowl Damage Your Heart? • Snow Storm Photos • Senior Class Gift Drive • SPINTfest \u2710 Brings New Themes for Houses • UC Goes Red to Raise Awareness About the Risks of Heart Disease • Opinion: Teenage Pregnancy TV Shows are a Big Hit, But What\u27s the Effect? • Tragedy Strikes in Early Hours of Winter Olympics • Men\u27s Basketball Shuts Down McDanielhttps://digitalcommons.ursinus.edu/grizzlynews/1806/thumbnail.jp
Local Entanglement Entropy and Mutual Information across the Mott Transition in the Two-Dimensional Hubbard Model
Entanglement and information are powerful lenses to probe phases transitions
in many-body systems. Motivated by recent cold atom experiments, which are now
able to measure the corresponding information-theoretic quantities, we study
the Mott transition in the half-filled two-dimensional Hubbard model using
cellular dynamical mean-field theory, and focus on two key measures of quantum
correlations: entanglement entropy and mutual information. We show that they
detect the first-order nature of the transition, the universality class of the
endpoint, and the crossover emanating from the endpoint.Comment: 6 pages, 3 figure
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