Training Sparse Mixture Of Experts Text Embedding Models
By Zach Nussbaum, Brandon Duderstadt. arXiv.org, 2025
44 citations recorded by the source corpus.
Transformer-based text embedding models have improved their performance on benchmarks like MIRACL and BEIR by increasing their parameter counts. However, this scaling approach introduces significant deployment challenges, including increased inference latency and memory usage. These challenges are particularly severe in retrieval-augmented generation (RAG) applications, where large models' increased memory requirements constrain dataset ingestion capacity, and their higher latency directly impacts query-time performance. While causal language models have addressed similar efficiency challenges using Mixture of Experts (MoE) architectures, this approach hasn't been successfully adapted to the general text embedding setting. In this paper, we introduce Nomic Embed v2, the first general purpose MoE text embedding model. Our model outperforms models in the same parameter class on both monolingual and multilingual benchmarks while also maintaining competitive performance with models twice its size. We open-source all code, models, and evaluation data to ensure full reproducibility of our training pipeline at \href{https://github.com/nomic-ai/contrastors}{https://github.com/nomic-ai/contrastors}.
Subfields: Information Retrieval & Search, Representation & Self-Supervised Learning, Model Architectures
View Paper: https://arxiv.org/abs/2502.07972
Citations in the corpus
- Mixture-of-Experts Language Models Can Be Strong and Efficient Retrievers (2026, unknown): “Nomic Embed v2 trains a purpose-built, BERT-scale MoE encoder for text embedding (Nussbaum and Duderstadt, 2025), while GritLM evaluates a single Mixtral-based model under a joint generative and embedding objective and reports lower MTEB retrieval effectiveness than its dense 7B counterpart…”
- Continuous Online Evaluation of Recommendation Strategies in Social Science Academic Search (2026, unknown): “In this study, we experimented with three embedding models: (1) paraphrase-multilingual-mpnet-base-v2 [64], (2) nomic-embed-text-v2-moe [58], and (3) all-MiniLM-L6-v2 5 .”
- Don't Contrast the Impossible: Region-Constrained Batching for Contrastive User Modeling on a Local Community Platform (2026, unknown): “For item features, we use embeddings obtained from a pretrained embedding model [8, 9], which takes an item’s title, content, metadata and image as input and produces the corresponding item representations.”
- MARS: Multi-hop Adaptive Retrieval and SPARQL Generation for KGQA (2026, unknown): “For the text embedding function ϕ , we use a trained sparse mixture-of-experts text embedding model [35] with d = 768 dimensions.”
- Temporal Preference Optimization for Unsupervised Retrieval (2026, unknown): “…retrievers to scale with large amounts of unlabeled documents, from early statistical methods (Jatowt et al., 2005; 2013; Berberich et al., 2010; Kanhabua & Nørv˚ag, 2010; Kanhabua et al., 2012) like BM25 (Robertson & Zaragoza, 2009) to recent neural embedding models (Nussbaum & Duderstadt, 2025).”
- HistoRAG: Embedding Historical Methodology in Retrieval-Augmented Generation Through Critical Technical Practice (2026, unknown): “…are generated using nomic-embed-text (Nussbaum et al., 2025), an open-source model with 768-dimensional embeddings and an 8,192-token context window, subsequently migrated to nomic-embed-text-v2-moe (Nussbaum and Duderstadt, 2025) for improved multilingual performance on the German-language corpus.”
- Advancing Arabic Reverse Dictionary Systems: A Transformer-Based Approach with Novel Dataset Construction (2026, unknown): “In contrast, v1 [26] 0.208 0.596 0.221 ATMv2 [28] 0.222 0.570 0.183 Nomic-embed-text-v2 [29] 0.215 0.587 0.145 mpnet [30] 0.225 0.562 0.22 L12 [30] 0.220 0.560 0.22 LaBSE [30] 0.221 0.570 0.17 CasedV1 [30] 0.226 0.560 0.21 Snowflake-arctic-embed [31] 0.207 0.607 0.117 Roberta (Eng-Ar) [15] 0.170…”
- SkMTEB: Slovak Massive Text Embedding Benchmark and Model Adaptation (2026, unknown): “…efficiency: Jina Embed-dings v4 (Günther et al., 2025) extends the line toward unified multimodal multilingual retrieval, Nomic Embed v2-MoE (Nussbaum and Duderstadt, 2025) applies sparse Mixture-of-Experts to text embeddings, and compact open models such as Gran-ite Embedding (Awasthy et…”
- Zero-Shot Semantic Re-Identification for Autonomous Driving: A VLM Baseline Study (2026, unknown): “5 27B (Q4-K-M) [15] • Gemma 4 E2B [16] We pair these with four text embedding models: • Embedding Gemma 300M [17] • Nomic Embed v2 305M [18] • Qwen3-Embedding 4B [19] • Qwen3-Embedding 8B [19] This yields a cross-product of description generators and encoders, allowing us to isolate the impact of…”
- Argus-Retriever: Vision-LLM Late-Interaction Retrieval with Region-Aware Query-Conditioned MoE for Visual Document Retrieval (2026, unknown): “In retrieval the idea has been explored more sparingly: Guo et al. (2025) apply a competitively-learned MoE to first-stage text retrieval; Nussbaum and Duderstadt (2025) train sparse-MoE text embedding models; and Sokli et al. (2025) study MoE in dense retrieval.”
- eMEM: A Hybrid Spatio-Temporal Memory System For Embodied Agents (2026, unknown): “Experiments use Qwen 3.6 (27B) [Qwen Team, 2025] as both agent and entity-extractor, gemma3:27b as the judge (the judge is held constant across all configurations), and nomic-embed-text-v2-moe [Nussbaum and Duderstadt, 2025] embeddings.”
- IdioLink: Retrieving Meaning Beyond Words Across Idiomatic and Literal Expressions (2026, unknown): “We assess encoder models: Contriever-based TART (Asai et al., 2023), the instruction-tuned multilingual E5 (Wang et al., 2024c), and Nomic-Embed-v2 (Nussbaum and Duderstadt, 2025).”