Ultrafast Coherent Manipulation of Trions in Site-Controlled Nanowire Quantum Dots

TL;DR

This paper demonstrates ultrafast all-optical coherent control of qubits in site-controlled nanowire quantum dots, showing their potential as scalable platforms for quantum information processing.

Contribution

It provides the first demonstration of complete coherent control of qubits in site-controlled nanowire quantum dots, bridging the gap with randomly-positioned quantum dots.

Findings

Successful ultrafast coherent manipulation of trions in site-controlled quantum dots.

Site-controlled quantum dots exhibit similar qubit control capabilities as random quantum dots.

Potential for scalable quantum hardware using site-controlled nanowire quantum dots.

Abstract

Physical implementations of large-scale quantum processors based on solid-state platforms benefit from realizations of quantum bits positioned in regular arrays. Self-assembled quantum dots are well-established as promising candidates for quantum optics and quantum information processing, but they are randomly positioned. Site-controlled quantum dots, on the other hand, are grown in pre-defined locations, but have not yet been sufficiently developed to be used as a platform for quantum information processing. In this letter we demonstrate all-optical ultrafast complete coherent control of a qubit formed by the single-spin/trion states of a charged site-controlled nanowire quantum dot. Our results show that site-controlled quantum dots in nanowires are promising hosts of charged-exciton qubits, and that these qubits can be cleanly manipulated in the same fashion as has been demonstrated in randomly-positioned quantum dot samples. Our findings suggest that many of the related excitonic qubit experiments that have been performed over the past 15 years may work well in the more scalable site-controlled systems, making them very promising for the realization of quantum hardware.