FINE-STRUCTURE IN THE OFF-RESONANCE CONDUCTANCE OF SMALL COULOMB-BLOCKADE SYSTEMS

We show how a fine, multiple-peak structure can arise in the off-reson ance, zero-bias conductance of Coulomb-blockade systems. In order to u nderstand how this effect comes about one must abandon the orthodox, m ean-field understanding of the Coulomb-blockade phenomenon and conside r quantum fluctuations in the occupation of the single-particle electr onic levels. We illustrate such an effect with a spinless Anderson-lik e model for multilevel systems and an equation-of-motion method for ca lculating Green's functions that combines two simple decoupling scheme s.