Many-body Tunneling and Nonequilibrium Dynamics of Doublons in Strongly Correlated Quantum Dots

Wenjie Hou,Yuandong Wang,Yijing Yan,Jianhua Wei,Zhengang Zhu

doi:10.1038/s41598-017-02728-7

Abstract

Quantum tunneling dominates coherent transport at low temperatures in many systems of great interest. In this work we report a many–body tunneling (MBT), by nonperturbatively solving the Anderson multi-impurity model, and identify it a fundamental tunneling process on top of the well–acknowledged sequential tunneling and cotunneling. We show that the MBT involves the dynamics of doublons in strongly correlated systems. Proportional to the numbers of dynamical doublons, the MBT can dominate the off–resonant transport in the strongly correlated regime. A T3/2–dependence of the MBT current on temperature is uncovered and can be identified as a fingerprint of the MBT in experiments. We also prove that the MBT can support the coherent long–range tunneling of doublons, which is well consistent with recent experiments on ultracold atoms. As a fundamental physical process, the MBT is expected to play important roles in general quantum systems.

Highlights

) is the operator that creates a spin-s corresponds to the operator for the electron number electron with energy i,s (i = 1, 2) in of dot i
The device leads are treated as noninteracting electron reservoirs and the Hamiltonian can be written as
The numerical results are considered to be quantitatively accurate with increasing truncated level and converge

Summary

Quantum Dots

Quantum tunneling dominates coherent transport at low temperatures in many systems of great interest. Quantum tunneling deeply involved many–body interactions (shortened with many–body tunneling (MBT)) inevitably exists and dominates in many strongly correlated systems. The doublon-holon (unoccupied sites) binding plays important role[12], which was proved to be closely related to the Mott transition and high-temperature superconductivity[13]. There have been extensive studies on the properties of doublons in Bose- and Fermi-Hubbard models in ultracold atoms[15,16,17,18,19,20,21,22]. The experiments of Fermi-Hubbard model (ultracold 40K atoms) found the decay rate of doublon scaling as τ−1 ∝ exp(−U/t), where U is the on-site electron-electron (e − e) interaction and t is the tunneling coupling between nearest-neighbor sites[16]. The intrinsic features of the MBT and doublon are studied and their universality is addressed

MBT in DQDs

Summary

Method

Additional Information