Tracking excited states in wave function optimization using density matrices and variational principles

We present a method for finding individual excited states' energy stationary points in complete active space self-consistent field theory that is compatible with standard optimization methods and highly effective at overcoming difficulties due to root flipping and near-degeneracies. Inspired by both the maximum overlap method and recent progress in excited state variational principles, our approach combines these ideas in order to track individual excited states throughout the orbital optimization process. In a series of tests involving root flipping, near-degeneracies, charge transfers, and double excitations, we show that this approach is more effective for state-specific optimization than either the naive selection of roots based on energy ordering or a more direct generalization of the maximum overlap method. Furthermore, we provide evidence that this state-specific approach improves the performance of complete active space perturbation theory. With a simple implementation, a low cost, and compatibility with large active space methods, the approach is designed to be useful in a wide range of excited state investigations.Comment: 13 pages, submitted to JCT

Theoretical study of stimulated and spontaneous Hawking effects from an acoustic black hole in a hydrodynamically flowing fluid of light

We propose an experiment to detect and characterize the analog Hawking radiation in an analog model of gravity consisting of a flowing exciton-polariton condensate. Under a suitably designed coherent pump configuration, the condensate features an acoustic event horizon for sound waves that at the semiclassical level is equivalent to an astrophysical black hole horizon. We show that a continuous-wave pump-and-probe spectroscopy experiment allows to measure the analog Hawking temperature from the dependence of the stimulated Hawking effect on the pump-probe detuning. We anticipate the appearance of an emergent resonant cavity for sound waves between the pump beam and the horizon, which results in marked oscillations on top of an overall exponential frequency dependence. We finally analyze the spatial correlation function of density fluctuations and identify the hallmark features of the correlated pairs of Bogoliubov excitations created by the spontaneous Hawking process, as well as novel signatures characterizing the emergent cavity

A profiling analysis of contributions of cigarette smoking, dietary calcium intakes, and physical activity to fragility fracture in the elderly

Fragility fracture and bone mineral density (BMD) are influenced by common and modifiable lifestyle factors. In this study, we sought to define the contribution of lifestyle factors to fracture risk by using a profiling approach. The study involved 1683 women and 1010 men (50+ years old, followed up for up to 20 years). The incidence of new fractures was ascertained by X-ray reports. A “lifestyle risk score” (LRS) was derived as the weighted sum of effects of dietary calcium intake, physical activity index, and cigarette smoking. Each individual had a unique LRS, with higher scores being associated with a healthier lifestyle. Baseline values of lifestyle factors were assessed. In either men or women, individuals with a fracture had a significantly lower age-adjusted LRS than those without a fracture. In men, each unit lower in LRS was associated with a 66% increase in the risk of total fracture (non-adjusted hazard ratio [HR] 1.66; 95% CI, 1.26 to 2.20) and still significant after adjusting for age, weight or BMD. However, in women, the association was uncertain (HR 1.30; 95% CI, 1.11 to 1.53). These data suggest that unhealthy lifestyle habits are associated with an increased risk of fracture in men, but not in women, and that the association is mediated by BMD

Value of Information in Improving Daily Operations in High-Density Logistics

In this paper we investigate the value of shared information between chain actors for improving daily operations in high-density logistics processes at distribution warehouses. We first define a generic high-density logistics process at a distribution warehouse based on real-world cases. Utilizing daily shared information about inbound flow (i.e. truck-arrival time) and outbound flow (i.e. required timeframes), we then propose daily process redesign on changing process parameters and evaluate their impact on the process performance using a discrete-event simulation model of a floricultural supply chain. Additionally, the impact of different information characteristics (i.e. timeliness, accuracy and completeness) on the effectiveness of the redesign decision are studied through different scenarios. This work contributes to a better understanding of the value of information in supporting decision-making at the operational level, particularly in warehouse operations. It also helps to raise the awareness of industrial managers regarding the use of information for improving process performance as well as the importance of information characteristics

Of Pride and Pencils: Deconstructing the Role of Ethnic Pride in Hmong Adolescent Identity Formation

This study examines the ways that Hmong adolescents describe ethnic pride and how their descriptions are informed by perceptions of collective and social identities. Data from semistructured interviews with 25 Hmong adolescents age 12-18 were thematically analyzed with attention to affective versus behavioral aspects of ethnic pride and the role of collective or social group identities in adolescent pride perceptions or expressions. Results indicate that Hmong adolescents view affective and behavioral components of ethnic pride as distinct and evaluated self and peer pride along these two dimensions. Moreover, pride was found to be defined as both an individual characteristic and a social construct, and the perception and expression of the term was informed by Hmong adolescent peer groups and collective identities

Evolution and diversity of passerine birds of Australasia

Passeriformes (passerines) is the largest and most diverse order of living birds, comprising over 50% of the world's avifauna. Because of their ubiquity, enormous diversity and exceptional plasticity, passerines represent an excellent vertebrate group for investigating a wide range of evolutionary, ecological and behavioural questions. However, these studies often require a well-resolved and robust phylogeny that incorporates not only morphological and molecular data, but also a broad sampling of modern and fossil taxa. The Australian fossil record is crucial to understanding the evolutionary history of passerines because much of their early evolution is presumed to have occurred in this region. However, the passerine fossil record is very scarce and poorly studied. Identifying passerine fossils is highly challenging both because of the large number of species (>5000) and because of the uniformity in their skeleton relative to other avian orders. This is problematic because phylogenetically informative characters are essential for identifying the systematic positions of fossils, resolving their relationships with living taxa, and understanding morphological evolution. This thesis addresses some of the shortcomings in our knowledge of passerine evolution and morphology. I describe pre-Quaternary (25 2.5 million years ago) fossil passerines from Riversleigh World Heritage Area, Queensland (Oligo-Miocene and Pliocene), and St Bathans, New Zealand (early Miocene). Many of the newly described fossils represent families previously unknown from these sites, and most are the oldest known representatives of extant passerine families. I present a comprehensive osteological database comprising novel and informative postcranial characters for the major modern groups of Australasian passerines. I employ these characters to infer the phylogenetic relationships of basal and higher-level taxa using maximum parsimony. I also use my osteological dataset to estimate the relationships of the Riversleigh passerines with living passerines. This dataset provides a useful resource for future research involving passerine morphology, including comparative, palaeontological and phylogenetic studies. Overall, the work presented here has considerably expanded our knowledge of the early history and diversity of the Australasian avifauna, shedding light on the evolution of the most widespread and diverse order of birds