Distinguishing particle-hole conjugated Fractional Quantum Hall states using quantum dot mediated edge transport

TL;DR

This paper proposes a theoretical method using quantum dot mediated edge transport to distinguish between different fractional quantum Hall states, including particle-hole conjugates and non-Abelian states, based on conductance behavior.

Contribution

It introduces a novel approach to identify fractional quantum Hall states by analyzing edge transport in the presence of quantum dots, revealing distinct conductance signatures.

Findings

Disorder-irrelevant phase: u=1/3 conductance vanishes, u=2/3 remains finite.

Disorder-dominated phase: u=1/3 conductance is (1/5)e^2/h, u=2/3 is (1/2)e^2/h.

At u=5/2, Pfaffian and anti-Pfaffian states show different conductance in the disorder-irrelevant phase.

Abstract

We study theoretically edge transport of a fractional quantum Hall liquid, in the presence of a quantum dot inside the Hall bar with well controlled electron density and Landau level filling factor \nu, and show that such transport studies can help reveal the nature of the fractional quantum Hall liquid. In our first example we study the \nu=1/3 and \nu=2/3 liquids in the presence of a \nu=1 quantum dot. When the quantum dot becomes large, its edge states join those of the Hall bar to reconstruct the edge states configuration. Taking randomness around the edges into account, we find that in the disorder-irrelevant phase the two-terminal conductance of the original \nu=1/3 system vanishes at zero temperature, while that of the \nu=2/3 case remains finite. This distinction is rooted in the fact that the \nu=2/3 state is built upon the \nu=1 state. In the disorder-dominated phase, the two-terminal conductance of \nu=1/3 system is (1/5)\frac{e^2}{h} and that of \nu=2/3 system is (1/2)\frac{e^2}{h}. We further apply the same idea to the \nu=5/2 system which realizes either the Pfaffian or the anti-Pfaffian states. In this case we study the edge transport in the presence of a central \nu=3 quantum dot. If the quantum dot is large enough for its edge states joining those of the Hall bar, in the disorder-irrelevant phase the total two-terminal conductance in the Pfaffian case is G^{Pf}_{tot}\rightarrow 2 \frac{e^2}{h} while that of anti-Pfaffian case is higher but not universal, G^{aPf}_{tot}> 2 \frac{e^2}{h}. This difference can be used to determine which one of these two states is realized at \nu=5/2. In the disorder-dominated phase, however, the total two-terminal conductances in these two systems are exactly the same, G^{Pf/aPf}_{tot}=(7/3)\frac{e^2}{h}.