Ultrafast initialization and QND-readout of a spin qubit via control of nanodot-vacuum coupling

TL;DR

This paper presents a method for ultrafast initialization and quantum non-demolition readout of a spin qubit by controlling nanodot-vacuum coupling, enabling scalable quantum computing.

Contribution

It introduces a novel approach to manipulate vacuum-nanodot coupling for fast spin initialization and QND readout using optical pump pulses and integrated photonic structures.

Findings

Efficient quantum pathway from electron spin to flying photon established.

Ultrafast spin initialization achieved through controlled nanodot-vacuum interaction.

QND readout compatible with optically driven spin quantum computers.

Abstract

Ultrafast initialization enables fault-tolerant processing of quantum information while QND readout enables scalable quantum computation. By spatially assembling photon resonators and wave-guides around an n-doped nanodot and by temporally designing optical pump pulses, an efficient quantum pathway can be established from an electron spin to a charged exciton to a cavity photon and finally to a flying photon in the waveguide. Such control of vacuum-nanodot coupling can be exploited for ultrafast initialization and QND readout of the spin, which are particularly compatible with the optically driven spin quantum computers.