Spin-to-polarization mapping with a coherent quantum dot-cavity receiver
Abstract
Coherent light-matter interfaces controllably modifying the state of a photon upon interaction with a stationary qubit are a key resource for implementing deterministic entangling gates for optical quantum technologies. This requires a one-to-one mapping between the state of the scattered photon and that of the embedded qubit. Here, we present an experimental signature of such a bijection by leveraging the spin-induced Kerr rotation present in a low-noise charged quantum dot-micropillar cavity device. Through time-resolved polarization measurements, we project the electron spin to one of its eigenstates with 95±2% fidelity with a single reflected photon detection, and follow the subsequent spin relaxation through the detection of a second reflected photon. We demonstrate that, after a transient regime governed by the trion radiative lifetime, two orthogonal polarization states can be produced, each associated to a given spin eigenstate. While the current results are limited by a timescale competition between electron spin relaxation and trion radiative lifetime, they could be improved using hole spins displaying increased relaxation times. Our work paves the way towards deterministic logic gates exploiting this one-to-one mapping between a spin and the polarization of a scattered photon.
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BibTeX
@misc{medeiros2026spintopolarization,
title = {{Spin-to-polarization mapping with a coherent quantum dot-cavity receiver}},
author = {Adrià Medeiros and Vincent Vinel and Eliott Rambeau and Petr Steindl and Elham Mehdi and Manuel Gundín and Clément Millet and Petr Stepanov and Niccolo Somaschi and Aristide Lemaître and Isabelle Sagnes and Olivier Krebs and Pascale Senellart and Dario A. Fioretto and Loïc Lanco},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.03910},
eprint = {2609.03910},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.03910},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Spin-to-polarization mapping with a coherent quantum dot-cavity receiver
AU - Adrià Medeiros
AU - Vincent Vinel
AU - Eliott Rambeau
AU - Petr Steindl
AU - Elham Mehdi
AU - Manuel Gundín
AU - Clément Millet
AU - Petr Stepanov
AU - Niccolo Somaschi
AU - Aristide Lemaître
AU - Isabelle Sagnes
AU - Olivier Krebs
AU - Pascale Senellart
AU - Dario A. Fioretto
AU - Loïc Lanco
PY - 2026
DA - 2026/09/03
PB - arXiv
DO - 10.48550/arxiv.2609.03910
UR - https://arxiv.org/abs/2609.03910
AB - Coherent light-matter interfaces controllably modifying the state of a photon upon interaction with a stationary qubit are a key resource for implementing deterministic entangling gates for optical quantum technologies. This requires a one-to-one mapping between the state of the scattered photon and that of the embedded qubit. Here, we present an experimental signature of such a bijection by leveraging the spin-induced Kerr rotation present in a low-noise charged quantum dot-micropillar cavity device. Through time-resolved polarization measurements, we project the electron spin to one of its eigenstates with 95±2% fidelity with a single reflected photon detection, and follow the subsequent spin relaxation through the detection of a second reflected photon. We demonstrate that, after a transient regime governed by the trion radiative lifetime, two orthogonal polarization states can be produced, each associated to a given spin eigenstate. While the current results are limited by a timescale competition between electron spin relaxation and trion radiative lifetime, they could be improved using hole spins displaying increased relaxation times. Our work paves the way towards deterministic logic gates exploiting this one-to-one mapping between a spin and the polarization of a scattered photon.
ER -