Condensed Matter Theory

Abstract:

We develop a phenomenological description of the [Formula presented] quantum Hall state in which the Halperin-Lee-Read theory of the half-filled Landau level is combined with a [Formula presented]-wave pairing interaction between composite fermions (CFs). The electromagnetic response functions for the resulting mean-field superconducting state of the CFs are calculated and used in an RPA calculation of the [Formula presented] and [Formula presented] dependent longitudinal conductivity of the physical electrons, a quantity which can be measured experimentally. © 2003 The American Physical Society.

Abstract:

A brief review is given of the minority game, an idealized model of a market of speculative agents, and its complex many-body behaviour. Particular consideration is given to the consequences and implications of correlations between strategies and different frequencies and timings of adaptation. (C) 2003 Elsevier Science B.V. All rights reserved.

Abstract:

We report on a study of the shape of a stiff, charged rod that is subjected to equal and opposite force couples at its two ends. Unlike a neutral elastic rod, which forms a constant curvature configuration under such influences, the charged rod tends to flatten in the interior and accumulate the curvature in the end points, to maximally reduce the electrostatic self-repulsion. The effect of this nonuniform bending on the effective elasticity and on the statistical conformations of a fluctuating charged rod is discussed. An alternative definition for the electrostatic persistence length is suggested. This definition is found to be consistent with a corresponding length that can be deduced from the end-to-end distribution function of a fluctuating polyelectrolyte.