4,440 research outputs found
Quench dynamics of a disordered array of dissipative coupled cavities
We investigate the mean-field dynamics of a system of interacting photons in
an array of coupled cavities in presence of dissipation and disorder. We follow
the evolution of on an initially prepared Fock state, and show how the
interplay between dissipation and disorder affects the coherence properties of
the cavity emission and that these properties can be used as signatures of the
many-body phase of the whole array.Comment: 8 pages, 10 figures, new reference adde
The English Civil War and the Glorious Revolution (10th-12th grade)
A 6 day unit (adjustable) on the causes of the English Civil War and the Glorious Revolution and how it affected English politics. Unit focuses on the involvement of religion in politics, absolutism, and the emergence of Parliament gaining more power and the consent of the governed
Culture and Identity in Novels Centered Around Women of Color
Designed to actually utilize the summer reading for rising sophomores, this unit focuses on culture and identity in the novels White Teeth by Zadie Smith, The House of the Spirits by Isabel Allende, and Crazy Brave by Joy Harjo. Students chose which of these books they wanted to read during the summer and the unit focuses on marrying the themes and characters of these books together. Students will be able to make text-to-text, text-to-self, and text-to-world connections through a persuasive one-pager and a creative final project where students will make connections from the novels to their world history class. Can easily be adapted to suit the needs of the teacher
Exotic attractors of the non-equilibrium Rabi-Hubbard model
We explore the phase diagram of the dissipative Rabi-Hubbard model, as could
be realized by a Raman-pumping scheme applied to a coupled cavity array. There
exist various exotic attractors, including ferroelectric, antiferroelectric,
and inccomensurate fixed points, as well as regions of persistent oscillations.
Many of these features can be understood analytically by truncating to the two
lowest lying states of the Rabi model on each site. We also show that these
features survive beyond mean-field, using Matrix Product Operator simulations.Comment: 5pages, 3 figures, plus supplementary material. Final version, as
publishe
Insights from unifying modern approximations to infections on networks
Networks are increasingly central to modern science owing to their ability to conceptualize multiple interacting components of a complex system. As a specific example of this, understanding the implications of contact network structure for the transmission of infectious diseases remains a key issue in epidemiology. Three broad approaches to this problem exist: explicit simulation; derivation of exact results for special networks; and dynamical approximations. This paper focuses on the last of these approaches, and makes two main contributions.
Firstly, formal mathematical links are demonstrated between several prima facie unrelated dynamical approximations. And secondly, these links are used to derive two novel dynamical models for network epidemiology, which are compared against explicit stochastic simulation. The success of these new models provides improved understanding about the interaction of network structure and transmission dynamics
Social encounter networks : collective properties and disease transmission
A fundamental challenge of modern infectious disease epidemiology is to quantify the networks of social and physical contacts through which transmission can occur. Understanding the collective properties of these interactions is critical for both accurate prediction of the spread of infection and determining optimal control measures. However, even the basic properties of such networks are poorly quantified, forcing predictions to be made based on strong assumptions concerning network structure. Here, we report on the results of a large-scale survey of social encounters mainly conducted in Great Britain. First, we characterize the distribution of contacts, which possesses a lognormal body and a power-law tail with an exponent of −2.45; we provide a plausible mechanistic model that captures this form. Analysis of the high level of local clustering of contacts reveals additional structure within the network, implying that social contacts are degree assortative. Finally, we describe the epidemiological implications of this local network structure: these contradict the usual predictions from networks with heavy-tailed degree distributions and contain public-health messages about control. Our findings help us to determine the types of realistic network structure that should be assumed in future population level studies of infection transmission, leading to better interpretations of epidemiological data and more appropriate policy decisions
Changes in column inventories of carbon and oxygen in the Atlantic Ocean
Increasing concentrations of dissolved inorganic carbon (DIC) in the interior ocean are expected as a direct consequence of increasing concentrations of CO<sub>2</sub> in the atmosphere. This extra DIC is often referred to as anthropogenic carbon (C<sub>ant</sub>), and its inventory, or increase rate, in the interior ocean has previously been estimated by a multitude of observational approaches. Each of these methods is associated with hard to test assumptions since C<sub>ant</sub> cannot be directly observed. Results from a simpler concept with fewer assumptions applied to the Atlantic Ocean are reported on here using two large data collections of carbon relevant bottle data. The change in column inventory on decadal time scales, i.e. the storage rate, of DIC, respiration compensated DIC and oxygen is calculated for the Atlantic Ocean. We report storage rates and the confidence intervals of the mean trend at the 95% level (CI), reflecting the mean trend but not considering potential biasing effects of the spatial and temporal sampling. For the whole Atlantic Ocean the mean trends for DIC and oxygen are non-zero at the 95% confidence level: DIC: 0.86 (CI: 0.72–1.00) and oxygen: −0.24 (CI: −0.41–(−0.07)) mol m<sup>−2</sup> yr<sup>−1</sup>. For oxygen, the whole Atlantic trend is dominated by the subpolar North Atlantic, whereas for other regions the O<sub>2</sub> trends are not significant. The storage rates are similar to changes found by other studies, although with large uncertainty. For the subpolar North Atlantic the storage rates show significant temporal and regional variation of all variables. This seems to be due to variations in the prevalence of subsurface water masses with different DIC and oxygen concentrations leading to sometimes different signs of storage rates for DIC compared to published C<sub>ant</sub> estimates. This study suggest that accurate assessment of the uptake of CO<sub>2</sub> by the oceans will require accounting not only for processes that influence C<sub>ant</sub> but also additional processes that modify CO<sub>2</sub> storage
Thinking Geographically Mapping Portfolio
This unit is designed to introduce the students to the foundations of thinking geographically. Students will create a map portfolio that applies to the big ideas of AP Human Geography. Students will critically analyze and reflect on the “why of where” to understand geographic perspective by utilizing quantitative and qualitative data. Students will turn in a map portfolio that will address purpose, patterns, and spatial relationships among places
Enhanced vaccine control of epidemics in adaptive networks
We study vaccine control for disease spread on an adaptive network modeling
disease avoidance behavior. Control is implemented by adding Poisson
distributed vaccination of susceptibles. We show that vaccine control is much
more effective in adaptive networks than in static networks due to an
interaction between the adaptive network rewiring and the vaccine application.
Disease extinction rates using vaccination are computed, and orders of
magnitude less vaccine application is needed to drive the disease to extinction
in an adaptive network than in a static one
A motif-based approach to network epidemics
Networks have become an indispensable tool in modelling infectious diseases, with the structure of epidemiologically relevant contacts known to affect both the dynamics of the infection process and the efficacy of intervention strategies. One of the key reasons for this is the presence of clustering in contact networks, which is typically analysed in terms of prevalence of triangles in the network. We present a more general approach, based on the prevalence of different four-motifs, in the context of ODE approximations to network dynamics. This is shown to outperform existing models for a range of small world networks
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