Charge Violation and Alice Behavior in Global and Textured Strings

Spontaneous breaking of global symmetries can produce ``Alice'' strings: line defects which make unbroken symmetries multivalued, induce apparent charge violation via Aharonov-Bohm interactions, and form point defects when twisted into loops. We demonstrate this behavior for both divergent and textured global Alice strings. Both adiabatically scatter charged particles via effective Wilson lines. For textured Alice strings, such Wilson lines occur at all radii, and are multivalued only inside the string. This produces measurable effects, including path-dependent charge violation.Comment: 32 pages, 2 epsfigs, Revte

Topologically Alice Strings and Monopoles

Symmetry breaking can produce ``Alice'' strings, which alter scattered charges and carry monopole number and charge when twisted into loops. Alice behavior arises algebraically, when strings obstruct unbroken symmetries -- a fragile criterion. We give a topological criterion, compelling Alice behavior or deforming it away. Our criterion, that \pi_o(H) acts nontrivially on \pi_1(H), links topologically Alice strings to topological monopoles. We twist topologically Alice loops to form monopoles. We show that Alice strings of condensed matter systems (nematic liquid crystals, helium 3A, and related non-chiral Bose condensates and amorphous chiral superconductors) are topologically Alice, and support fundamental monopole charge when twisted into loops. Thus they might be observed indirectly, not as strings, but as loop-like point defects. We describe other models, showing Alice strings failing our topological criterion; and twisted Alice loops supporting deposited, but not fundamental, monopole number.Comment: 2 figures; this paper consolidates preprints hep-th/0304161 and hep-th/0304162, to appear in Phys. Rev.

Terrestrial planets across space and time

The study of cosmology, galaxy formation and exoplanets has now advanced to a stage where a cosmic inventory of terrestrial planets may be attempted. By coupling semi-analytic models of galaxy formation to a recipe that relates the occurrence of planets to the mass and metallicity of their host stars, we trace the population of terrestrial planets around both solar-mass (FGK type) and lower-mass (M dwarf) stars throughout all of cosmic history. We find that the mean age of terrestrial planets in the local Universe is $7\pm{}1$ Gyr for FGK hosts and $8\pm{}1$ Gyr for M dwarfs. We estimate that hot Jupiters have depleted the population of terrestrial planets around FGK stars by no more than $\approx 10\%$, and that only $\approx 10\%$ of the terrestrial planets at the current epoch are orbiting stars in a metallicity range for which such planets have yet to be confirmed. The typical terrestrial planet in the local Universe is located in a spheroid-dominated galaxy with a total stellar mass comparable to that of the Milky Way. When looking at the inventory of planets throughout the whole observable Universe, we argue for a total of $\approx 1\times 10^{19}$ and $\approx 5\times 10^{20}$ terrestrial planets around FGK and M stars, respectively. Due to light travel time effects, the terrestrial planets on our past light cone exhibit a mean age of just $1.7\pm 0.2$ Gyr. These results are discussed in the context of cosmic habitability, the Copernican principle and searches for extraterrestrial intelligence at cosmological distances.Comment: 11 pages, 8 figures. v.2: Accepted for publication in ApJ. Some changes in quantitative results compared to v.1, mainly due to differences in IMF assumption

Ab initio description of nonlinear dynamics of coupled microdisk resonators with application to self-trapping dynamics

Ab initio approach is used to describe the time evolution of the amplitudes of whispering gallery modes in a system of coupled microdisk resonators with Kerr nonlinearity. It is shown that this system demonstrates a transition between Josephson-like nonlinear oscillations and self-trapping behavior. Manifestation of this transition in the dynamics of radiative losses is studied.Comment: 10 pages, 5 figures, accepted for publication in Phys. Rev.

Unpacking distinction within mobility : social prestige and international students

Author thanks the Social Sciences and Humanities Research Council of Canada (SSHRC) for their funding on this projecThis paper investigates the complex ways in which young people engage in social distinction within international mobility. The study offers novel conceptual and empirical insights by examining how distinction and social advantage is reproduced through short‐term student mobility from the Global North to the Global South. In doing so, it elucidates the iterative process of distinction‐making within mobility and argues that young mobile people negotiate a tension between different forms of distinction. Specifically, it unpacks and conceptualises distinction into dual categories—collective and individual—and suggests that students alternate and waver between these categories in order to both validate and elevate their position within a mobility hierarchy. The paper also considers how particular places are viewed as more distinctive and affording greater gains in cultural and symbolic capital. It concludes with future interrogations and ways forward for research on international mobility and distinction.PostprintPeer reviewe

The Effects of Self-Selected Music on Exercise Performance

Please see the pdf version of the abstract

Move, Adapt, or Die: Lagopus Leucura Changes in Distribution, Habitat and Number at Glacier National Park, Montana

ABSTRACT.—Because of the “montane island” effect and relative rates of climate change, alpine species may be particularly affected by changing climate. White-tailed Ptarmigan (Lagopus leucura) are adapted to life in the alpine cold, but may be less well-adapted to hot summer temperatures. In 1996 and 1997, ptarmigan living in Glacier National Park (GNP) were closely associated with remnant snow and free water in the late summer, a resource that is rapidly changing in distribution and extent as climate changes. We examined White-tailed Ptarmigan distribution, habitat, and numbers in 2009-2010 for comparison with 1996-1997 data. Briefly, five areas within GNP were searched for ptarmigan during August. Habitat data including microclimate were collected at flock locations. Microclimate at ptarmigan flock locations differed from other areas nearby. Flocking ptarmigan appeared to be less numerous than described in 1996 and 1997, and mean flock locations on Logan Pass moved 335 m upslope between the 1990s and 2009 and 2010. Ptarmigan in 2009 and 2010 chose habitat that had the same coverage of vegetation and rock as 1996 and 1997, but contained less snow and water, was farther from snow and water, contained lower soil moisture content, was higher in elevation, and steeper in slope. Our study demonstrates that White-tailed Ptarmigan in GNP have changed distribution, altered habitat preferences, and perhaps on a local scale, experienced declining population numbers in late summer

Chemical Analyses of Water from Selected Wells and Springs in the Yucca Mountain Area, Nevada and Southeastern California

Chemical analysis of water samples from 279 wells and springs in the Yucca Mountain area are presented. Where data are available, this report includes: site location expressed as Nevada Central Coordinates and latitude and longitude; source of data; name of analyzing laboratory; geologic unit from which water was obtained; lithology; water use; elevation of well or spring; well depth; depth to water; time pumped before taking the sample; yield; type of filtration; sampling method; date the sample was collected; and anion-cation balance. Yucca Mountain, Nevada (fig. 1), is being investigated by the U.S. Geological Survey, in cooperation with the U.S. Department of Energy, as a possible repository for the disposal of high-level nuclear wastes. Yucca Mountain is underlain by partially altered volcanic tuffs that probably extend to depths greater than 3,000 m (Snyder and Carr, 1982). If approved, the repository will most likely be excavated within the unsaturated zone, 150 to 300 m above the water table. One concern is that radionuclides might be leached from the stored wastes and eventually reach the saturated zone, where they would be transported in the ground-water system away from the repository. The purpose of this report is to present a data base that consolidates the available ground-water data for the area surrounding the potential Yucca Mountain nuclear-waste repository. The objective of assembling this data is to provide a data base that potentially could be used to help determine: (1) Ground-water flow paths; (2) velocities and residence times of ground water; (3) the degree of vertical and lateral chemical heterogeneity of the ground-water system; and (4) chemical processes that affect the potential movement radionuclide species