Steve Simon

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:

In this paper, we consider a narrowband point-to-point communication system with nT transmitters and nR receivers. We assume the receiver has perfect knowledge of the channel, while the transmitter has no channel knowledge. We consider the case where the receiving antenna array has uncorrelated elements, while the elements of the transmitting array are arbitrarily correlated. Focusing on the case where nT = 2, we derive simple analytic expressions for the ergodic average and the cumulative distribution function of the mutual information for arbitrary input (transmission) signal covariance. We then determine the ergodic and outage capacities and the associated optimal input signal covariances. We thus show how a transmitter with covariance knowledge should correlate its transmissions to maximize throughput. These results allow us to derive an exact condition (both necessary and sufficient) that determines when beamforming is optimal for systems with arbitrary number of transmitters and receivers.

Abstract:

A numerical method was formulated to study braiding statistics of FQH excitations. The method was applied to perform the first direct calculation of the non-Abelian statistics in the MR state. Results confirm previous data drawn within the CFT framework.