Dynamical properties of a nonequilibrium quantum dot close to a dissipative quantum phase transition

Chung-Hou Chung*

*Corresponding author for this work

研究成果: Article

摘要

The dynamical decoherence rate and charge susceptibility of a nonequilibrium quantum dot close to a dissipative quantum phase transition are calculated. The setup concerns a resonance-level quantum dot coupled to two spinless fermionic baths with a finite bias voltage and an ohmic bosonic bath representing a dissipative environment. The system is equivalent to an anisotropic Kondo model. As dissipation strength increases, the system at zero temperature and zero bias exhibits a quantum phase transition of the Kosterlitz-Thouless (KT) type between a conducting delocalized phase and an insulating localized phase. Within the nonequilibrium frequency-dependent renormalization group (RG) approach, the finite bias crossover in dynamical decoherence rate and charge susceptibility close to the transition are addressed. The dynamical decoherence rate is found to increase with increasing frequency. In the delocalized phase, it shows a singularity at frequencies equal to positive or negative bias voltage. As the system cross overs to the localized phase, the decoherence rate at low frequencies gets progressively smaller and the singular feature is gradually smeared out, leading to a single linear frequency dependence. The dynamical charge susceptibility at low frequencies shows a dip-to-peak crossover across the transition. Relevance of these results to the experiments is discussed.

原文English
文章編號115308
期刊Physical Review B - Condensed Matter and Materials Physics
83
發行號11
DOIs
出版狀態Published - 7 三月 2011

指紋 深入研究「Dynamical properties of a nonequilibrium quantum dot close to a dissipative quantum phase transition」主題。共同形成了獨特的指紋。

  • 引用此