Towards Rare-Earth Molecular Crystals as a New Platform in Quantum Networks
Bibliographic record
Abstract
Rare-Earth (RE) atoms possess a unique atomic energy level structure, leading to excellent electronic and spin coherence properties [1]. Consequently, RE-ion-doped materials are promising candidates for implementing light-matter interfaces for photonic quantum technologies, such as quantum memories. To exploit these properties in quantum technologies, the REs must be hosted in a solid-state material [1]. RE organic molecular crystals offer advantages over the well-known RE-doped inorganic crystals. In organic molecular crystals, RE ions are integral parts of the molecular structure, unlike in inorganic crystals, in which the RE ions are distributed randomly into the crystal lattice structure. This can potentially lead to narrower inhomogeneous broadening. These crystals provide unmatched flexibility in combining with photonic structures and in material composition, allowing the choice of different ligands and point group symmetries around the RE ion [2], [10], [4]. Our research focuses on crystals formed from a molecular complex hosting erbium ions$\lceil{E}r(C_{5}H_{7}O_{2})_{3}(C_{12}H_{8}N_{2})\rceil$. As these crystals have not yet been studied for quantum information purposes, we conducted a series of optical spectroscopy measurements to characterize the platform. We performed absorption measurements and obtained the absorption profiles at room and cryogenic temperatures. The results show a narrow inhomogeneous broadening in samples with different relative concentrations, even at 100%, for which all molecules contain an erbium ion. We measured the lifetime of the second lowest crystal field level of the ground state manifold$(\boldsymbol{30}\ cm^{-1}$above ground state) to be 1.759 seconds. Additionally, we measured the inhomogeneous broadening of the lowest crystal field level versus temperature to investigate the effects of phonon processes. Finally, under an external magnetic field, we observed Zeeman splitting and determined the g-factor to be 3.23 for erbium ions in this molecular complex.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".