Observation of "Partial Coherence" in an Aharonov-Bohm Interferometer with a Quantum Dot

TL;DR

This paper demonstrates partial coherence in an Aharonov-Bohm interferometer with a quantum dot, showing how spin entanglement causes quantum dephasing and affects interference amplitude.

Contribution

It provides experimental evidence of partial coherence due to spin entanglement in a quantum dot within an AB interferometer, linking spin-flip processes to dephasing.

Findings

AB amplitude varies with gate voltage across a spin-pair state

Asymmetry in amplitude matches theoretical spin-flip dephasing predictions

Evidence of partial coherence from spin entanglement in the system

Abstract

We report experiments on the interference through spin states of electrons in a quantum dot (QD) embedded in an Aharonov-Bohm (AB) interferometer. We have picked up a spin-pair state, for which the environmental conditions are ideally similar and have traced the AB amplitude in the range of the gate voltage that covers the pair. The behavior of the asymmetry in the amplitude around the two Coulomb peaks agrees with the theoretical prediction that relates a spin-flip process in a QD to the quantum dephasing of electrons. These results consist evidence of "partial coherence" due to an entanglement of spins in the QD and the interferometer.