Effect of quantum noise on Coulomb blockade in normal tunnel junctions at high voltages

TL;DR

This study explores how quantum noise influences Coulomb blockade phenomena in normal tunnel junctions at high voltages, revealing a slow approach to linear behavior and confirming theoretical models involving environmental interactions.

Contribution

It provides experimental validation of quantum theory predictions on environmental effects in tunnel junctions at high voltages, emphasizing the importance of frequency-dependent phase velocity.

Findings

Better fit with 1/sqrt{V} dependence supports quantum interaction models.

Experimental results align with the horizon picture using frequency-dependent phase velocity.

Coulomb blockade behavior persists at high voltages with slow asymptotic approach.

Abstract

We have investigated asymptotic behavior of normal tunnel junctions at voltages where even the best ohmic environments start to look like RC transmission lines. In the experiments, this is manifested by an exceedingly slow approach to the linear behavior above the Coulomb gap. As expected on the basis of the quantum theory taking into account interaction with the environmental modes, better fits are obtained using 1/sqrt{V}- than 1/V- dependence for the asymptote. These results agree with the horizon picture if the frequency-dependent phase velocity is employed instead of the speed of light in order to determine the extent of the surroundings seen by the junction.