Interference and interaction effects in multi-level quantum dots

Abstract

Using renormalization group techniques, we study spectral and transport properties of a spinless interacting quantum dot consisting of two levels coupled to metallic reservoirs. For strong Coulomb repulsion $U$ and an applied Aharonov-Bohm phase $\varphi$, we find a large direct tunnel splitting $|\Delta |\sim (\Gamma /\pi )|\cos (\varphi /2)|\ln (U/{\omega }_c)$ between the levels of the order of the level broadening $\Gamma$. As a consequence we discover a many-body resonance in the spectral density that can be measured via the absorption power. Furthermore, for $\varphi =\pi$, we show that the system can be tuned into an effective Anderson model with spin-dependent tunneling.

5 pages, 4 figures included, typos corrected