739 research outputs found
Habitus, Symbolic Violence, and Reflexivity: Applying Bourdieu’s Theories to Social Work
During the mid- to late-twentieth century, Pierre Bourdieu crated a conceptual framework that describes how underclass status becomes embodied in individuals, and the ways that personal, professional, and political fields perpetuate this oppression. Bourdieu’s theories also outline the role of the “critical intellectual” in undermining oppression and fighting for social justice. Using key terms from Bourdieu’s explanatory framework, this article examines the power relations and symbolic violence built into the interactions between social workers and clients, and offers suggestions as to how reflexive and relational social work can help workers reduce this impact. This paper also explores the role of social workers in addressing social inequalities by examining Bourdieu’s writings in terms of macro approaches to disparity
Raman Scattering and Anomalous Current Algebra: Observation of Chiral Bound State in Mott Insulators
Recent experiments on inelastic light scattering in a number of insulating
cuprates [1] revealed a new excitation appearing in the case of crossed
polarizations just below the optical absorption threshold. This observation
suggests that there exists a local exciton-like state with an odd parity with
respect to a spatial reflection. We present the theory of high energy large
shift Raman scattering in Mott insulators and interpret the experiment [1] as
an evidence of a chiral bound state of a hole and a doubly occupied site with a
topological magnetic excitation. A formation of these composites is a crucial
feature of various topological mechanisms of superconductivity. We show that
inelastic light scattering provides an instrument for direct measurements of a
local chirality and anomalous terms in the electronic current algebra.Comment: 18 pages, TeX, C Version 3.
Orthogonality catastrophe and shock waves in a non-equilibrium Fermi gas
A semiclassical wave-packet propagating in a dissipationless Fermi gas
inevitably enters a "gradient catastrophe" regime, where an initially smooth
front develops large gradients and undergoes a dramatic shock wave phenomenon.
The non-linear effects in electronic transport are due to the curvature of the
electronic spectrum at the Fermi surface. They can be probed by a sudden
switching of a local potential. In equilibrium, this process produces a large
number of particle-hole pairs, a phenomenon closely related to the
Orthogonality Catastrophe. We study a generalization of this phenomenon to the
non-equilibrium regime and show how the Orthogonality Catastrophe cures the
Gradient Catastrophe, providing a dispersive regularization mechanism. We show
that a wave packet overturns and collapses into modulated oscillations with the
wave vector determined by the height of the initial wave. The oscillations
occupy a growing region extending forward with velocity proportional to the
initial height of the packet. We derive a fundamental equation for the
transition rates (MKP-equation) and solve it by means of the Whitham modulation
theory.Comment: 5 pages, 1 figure, revtex4, pr
Quantum Shock Waves - the case for non-linear effects in dynamics of electronic liquids
Using the Calogero model as an example, we show that the transport in
interacting non-dissipative electronic systems is essentially non-linear.
Non-linear effects are due to the curvature of the electronic spectrum near the
Fermi energy. As is typical for non-linear systems, propagating wave packets
are unstable. At finite time shock wave singularities develop, the wave packet
collapses, and oscillatory features arise. They evolve into regularly
structured localized pulses carrying a fractionally quantized charge - {\it
soliton trains}. We briefly discuss perspectives of observation of Quantum
Shock Waves in edge states of Fractional Quantum Hall Effect and a direct
measurement of the fractional charge
Chiral non-linear sigma-models as models for topological superconductivity
We study the mechanism of topological superconductivity in a hierarchical
chain of chiral non-linear sigma-models (models of current algebra) in one,
two, and three spatial dimensions. The models have roots in the 1D
Peierls-Frohlich model and illustrate how the 1D Frohlich's ideal conductivity
extends to a genuine superconductivity in dimensions higher than one. The
mechanism is based on the fact that a point-like topological soliton carries an
electric charge. We discuss a flux quantization mechanism and show that it is
essentially a generalization of the persistent current phenomenon, known in
quantum wires. We also discuss why the superconducting state is stable in the
presence of a weak disorder.Comment: 5 pages, revtex, no figure
Lehmann-Symanzik-Zimmermann Reduction Approach to Multi-Photon Scattering in Coupled-Resonator Arrays
We present a quantum field theoretical approach based on the
Lehmann-Symanzik-Zimmermann reduction for the multi-photon scattering process
in a nano-architecture consisting of the coupled resonator arrays (CRA), which
are also coupled to some artificial atoms as the controlling quantum node. By
making use of this approach, we find the bound states of single photon for an
elementary unit, the T-type CRA, and explicitly obtain its multi-photon
scattering S-matrix in various situations. We also use this method to calculate
the multi-photon S-matrices for the more complex quantum network constructed
with main T-type CRA's, such as a H-type CRA waveguide.Comment: 15 pages, 14 figure
Matrix eigenvalue model: Feynman graph technique for all genera
We present the diagrammatic technique for calculating the free energy of the
matrix eigenvalue model (the model with arbitrary power by the
Vandermonde determinant) to all orders of 1/N expansion in the case where the
limiting eigenvalue distribution spans arbitrary (but fixed) number of disjoint
intervals (curves).Comment: Latex, 27 page
Integrability in SFT and new representation of KP tau-function
We are investigating the properties of vacuum and boundary states in the CFT
of free bosons under the conformal transformation. We show that transformed
vacuum (boundary state) is given in terms of tau-functions of dispersionless KP
(Toda) hierarchies. Applications of this approach to string field theory is
considered. We recognize in Neumann coefficients the matrix of second
derivatives of tau-function of dispersionless KP and identify surface states
with the conformally transformed vacuum of free field theory.Comment: 25 pp, LaTeX, reference added in the Section 3.
Quantum Hydrodynamics, Quantum Benjamin-Ono Equation, and Calogero Model
Collective field theory for Calogero model represents particles with
fractional statistics in terms of hydrodynamic modes -- density and velocity
fields. We show that the quantum hydrodynamics of this model can be written as
a single evolution equation on a real holomorphic Bose field -- quantum
integrable Benjamin-Ono equation. It renders tools of integrable systems to
studies of nonlinear dynamics of 1D quantum liquids.Comment: 5 pages, 1 figur
Magnetic properties of the Anderson model: a local moment approach
We develop a local moment approach to static properties of the symmetric
Anderson model in the presence of a magnetic field, focussing in particular on
the strong coupling Kondo regime. The approach is innately simple and
physically transparent; but is found to give good agreement, for essentially
all field strengths, with exact results for the Wilson ratio, impurity
magnetization, spin susceptibility and related properties.Comment: 7 pages, 3 postscript figues. Latex 2e using the epl.cls Europhysics
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