Opportunistic full reconstruction of 100-dimensional frequency-bin quantum states
Abstract
Frequency-bin encoding provides a scalable platform for photonic quantum information processing by enabling high-dimensional qudit states compatible with the telecommunications infrastructure. However, characterizing these systems remains challenging, as conventional quantum state tomography requires measurement resources that increase rapidly with dimensionality, compounded by the difficulty of implementing controllable measurements across many frequency modes at once. Here, we address these challenges and demonstrate threshold quantum state tomography of entangled frequency-bin qudits using adaptive measurements that exploit the sparsity of highly entangled biphoton frequency combs. Combined with Bayesian inference, we experimentally demonstrate full state estimation of biphoton frequency combs with Hilbert space dimensions up to d2=100---a 56% increase over the previous record---all while performing a mere 1.9% of the measurements required by conventional tomographically complete approaches. This work confirms the promise of measurement-aware approaches for characterizing high-dimensional photonic quantum systems, unlocking new tools for full tomography that are hardware-efficient, state-aware, and free from a priori assumptions about state structure.
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BibTeX
@misc{nguyen2026opportunistic,
title = {{Opportunistic full reconstruction of 100-dimensional frequency-bin quantum states}},
author = {Hanson H. Nguyen and Zachary Goisman and Chen-You Su and Diego Maragnano and Marco Liscidini and Jason D. McKinney and Hsuan-Hao Lu and Joseph M. Lukens},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.03496},
eprint = {2610.03496},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.03496},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Opportunistic full reconstruction of 100-dimensional frequency-bin quantum states
AU - Hanson H. Nguyen
AU - Zachary Goisman
AU - Chen-You Su
AU - Diego Maragnano
AU - Marco Liscidini
AU - Jason D. McKinney
AU - Hsuan-Hao Lu
AU - Joseph M. Lukens
PY - 2026
DA - 2026/10/02
PB - arXiv
DO - 10.48550/arxiv.2610.03496
UR - https://arxiv.org/abs/2610.03496
AB - Frequency-bin encoding provides a scalable platform for photonic quantum information processing by enabling high-dimensional qudit states compatible with the telecommunications infrastructure. However, characterizing these systems remains challenging, as conventional quantum state tomography requires measurement resources that increase rapidly with dimensionality, compounded by the difficulty of implementing controllable measurements across many frequency modes at once. Here, we address these challenges and demonstrate threshold quantum state tomography of entangled frequency-bin qudits using adaptive measurements that exploit the sparsity of highly entangled biphoton frequency combs. Combined with Bayesian inference, we experimentally demonstrate full state estimation of biphoton frequency combs with Hilbert space dimensions up to d^2=100---a 56% increase over the previous record---all while performing a mere 1.9% of the measurements required by conventional tomographically complete approaches. This work confirms the promise of measurement-aware approaches for characterizing high-dimensional photonic quantum systems, unlocking new tools for full tomography that are hardware-efficient, state-aware, and free from a priori assumptions about state structure.
ER -