Do correlations create an energy gap in electronic bilayers? Critical analysis of different approaches

This paper investigates the effect of correlations in electronic bilayers on the longitudinal collective mode structure. We employ the dielectric permeability constructed by means of the classical theory of moments. It is shown that the neglection of damping processes overestimates the role of correlations. We conclude that the correct account of damping processes leads to an absence of an energy gap.Comment: 4 page

Phases in Strongly Coupled Electronic Bilayer Liquids

The strongly correlated liquid state of a bilayer of charged particles has been studied via the HNC calculation of the two-body functions. We report the first time emergence of a series of structural phases, identified through the behavior of the two-body functions.Comment: 5 pages, RevTEX 3.0, 4 ps figures; Submitted to Phys. Rev. Let

Effect of the Coulomb repulsion on the {\it ac} transport through a quantum dot

We calculate in a linear response the admittance of a quantum dot out of equilibrium. The interaction between two electrons with opposite spins simultaneously residing on the resonant level is modeled by an Anderson Hamiltonian. The electron correlations lead to the appearence of a new feature in the frequency dependence of the conductance. For certain parameter values there are two crossover frequencies between a capacitive and an inductive behavior of the imaginary part of the admittance. The experimental implications of the obtained results are briefly discussed.Comment: 13 pages, REVTEX 3.0, 2 .ps figures from [email protected], NUB-308

Collective Modes in Strongly Coupled Elecronic Bilayer Liquids

We present the first reliable calculation of the collective mode structure of a strongly coupled electronic bilayer. The calculation is based on a classical model through the $3^{rd}$ frequency-moment-sum-rule preserving Quasi Localized Charge Approximation, using the recently calculated Hypernetted Chain pair correlation functions. The spectrum shows an energy gap at $k=0$ and the absence of a previously conjectured dynamical instability.Comment: 4 pages, 4 .ps figure