Influence of $\mathcal{PT}$-symmetric complex potentials on the decoupling mechanism in quantum transport process

TL;DR

This paper investigates how $ ext{PT}$-symmetric complex potentials influence decoupling and antiresonance phenomena in quantum transport through a quantum-dot chain, revealing transformations in transport behavior due to non-Hermitian effects.

Contribution

It demonstrates the impact of $ ext{PT}$-symmetric potentials on decoupling and antiresonance in quantum transport, highlighting the role of non-Hermitian effects in modifying transport phenomena.

Findings

Decoupling occurs at specific molecular states in Hermitian systems.

$ ext{PT}$ symmetry transforms decoupling into Fano antiresonance.

Magnetic flux can interchange roles of molecular states.

Abstract

We consider one system in which the terminal dots of a one-dimensional quantum-dot chain couple equally to the left and right leads and study the influence of $\mathcal{PT}$-symmetric complex potentials on the quantum transport process. It is found that in the case of the Hermitian Hamiltonian, remarkable decoupling and antiresonance phenomena have an opportunity to co-occur in the transport process. For the chains with odd(even) dots, all their even(odd)-numbered molecular states decouple from the leads. Meanwhile, antiresonance occurs at the positions of the even(odd)-numbered eigenenergies of the sub-chains without terminal dots. When the $\mathcal{PT}$-symmetric complex potentials are introduced to the terminal dots, the decoupling phenomenon is found to transform into the Fano antiresonance. In addition, it shows that appropriate magnetic flux can interchange the roles of the odd and even molecular states. These results can assist to understand the quantum transport modified by the $\mathcal{PT}$ symmetry in non-Hermitian discrete systems.