Coherent Tunneling by Adiabatic Passage of an exchange-only spin qubit in a double quantum dot chain

TL;DR

This paper demonstrates a scheme for coherent tunneling by adiabatic passage of exchange-only spin qubits in a double quantum dot chain, highlighting electrical control and robustness against dephasing for quantum computing.

Contribution

It introduces a novel CTAP-based method for adiabatic transfer of exchange-only spin qubits in a linear quantum dot chain, emphasizing electrical manipulation and minimal internal state population.

Findings

Successful adiabatic transfer without populating internal states

External states show transient populations during transport

Dephasing effects impact tunneling efficiency

Abstract

A scheme based on Coherent Tunneling by Adiabatic Passage (CTAP) of exchange-only spin qubit quantum states in a linearly arranged double quantum dot chain is demonstrated. Logical states for the qubit are defined by adopting the spin state of three electrons confined in a double quantum dot. The possibility to obtain gate operations entirely with electrical manipulations makes this qubit a valuable architecture in the field of quantum computing for the implementation of quantum algorithms. The effect of the external control parameters as well as the effect of the dephasing on the coherent tunneling in the chain is studied. During adiabatic transport, within a constant energy degenerate eigenspace, the states in the double quantum dots internal to the chain are not populated, while transient populations of the mixed states in the external ones are predicted.