179 research outputs found
The Most Embarrassing Thing that Ever Happened: Conversational Stories in a Theory of Enactment
Paper
Effect of anisotropy on the ground-state magnetic ordering of the spin-one quantum -- model on the square lattice
We study the zero-temperature phase diagram of the
-- Heisenberg model for spin-1 particles on an
infinite square lattice interacting via nearest-neighbour () and
next-nearest-neighbour () bonds. Both bonds have the same -type
anisotropy in spin space. The effects on the quasiclassical N\'{e}el-ordered
and collinear stripe-ordered states of varying the anisotropy parameter
is investigated using the coupled cluster method carried out to high
orders. By contrast with the spin-1/2 case studied previously, we predict no
intermediate disordered phase between the N\'{e}el and collinear stripe phases,
for any value of the frustration , for either the -aligned () or -planar-aligned () states. The quantum phase
transition is determined to be first-order for all values of and
. The position of the phase boundary is determined
accurately. It is observed to deviate most from its classical position (for all values of ) at the Heisenberg isotropic point
(), where . By contrast, at the XY
isotropic point (), we find . In the
Ising limit () as expected.Comment: 20 pages, 5 figure
Analytic Trajectories for Mobility Edges in the Anderson Model
A basis of Bloch waves, distorted locally by the random potential, is
introduced for electrons in the Anderson model. Matrix elements of the
Hamiltonian between these distorted waves are averages over infinite numbers of
independent site-energies, and so take definite values rather than
distributions of values. The transformed Hamiltonian is ordered, and may be
interpreted as an itinerant electron interacting with a spin on each site. In
this new basis, the distinction between extended and localized states is clear,
and edges of the bands of extended states, the mobility edges, are calculated
as a function of disorder. In two dimensions these edges have been found in
both analytic and numerical applications of tridiagonalization, but they have
not been found in analytic approaches based on perturbation theory, or the
single-parameter scaling hypothesis; nor have they been detected in numerical
approaches based on scaling or critical distributions of level spacing. In both
two and three dimensions the mobility edges in this work are found to separate
with increasing disorder for all disorders, in contrast with the results of
calculation using numerical scaling for three dimensions. The analytic
trajectories are compared with recent results of numerical tridiagonalization
on samples of over 10^9 sites. This representation of the Anderson model as an
ordered interacting system implies that in addition to transitions at mobility
edges, the Anderson model contains weaker transitions characterized by critical
disorders where the band of extended states decouples from individual sites;
and that singularities in the distribution of site energies, rather than its
second moment, determine localization properties of the Anderson model.Comment: 32 pages, 2 figure
Resolving identity ambiguity through transcending fandom
Identity construction involves accumulating cultural, social, and symbolic capital, with initial endowments being accrued through socialization into one’s habitus. This research explores the experiences of individuals that feel a lack of capital, which leads to ambiguity regarding their identities and places in the world. Through in-depth interviews, this interpretive research shows that such individuals may turn to fandom for gaining status and belonging. Fandoms are consumption fields with clear, limited forms of cultural capital. Through serial fandom and engagement with fandom in different ways, individuals were able to learn the skill of identifying and accruing relevant cultural capital. The skill became decontextualized and recontextualized, allowing individuals to transcend fandom and accrue general forms of cultural capital. Learning the skill aids individuals in dealing with the simultaneously debilitating and empowering freedom of contemporary consumer culture. Moreover, gaining cultural capital could be altogether developing into the form of the process we describe
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