AI ML Engineer

Optum is seeking a highly skilled AI ML Engineer for its Hyderabad, Telangana location. This role involves the end-to-end training and fine-tuning of Large Language Models (LLMs), including both open-source (e.g., Qwen, LLaMA, Mistral) and closed-source (e.g., OpenAI, Gemini, Anthropic) models. You will architect and implement GraphRAG pipelines, design and train semantic and dense vector embeddings, and develop semantic retrieval systems with advanced document segmentation and indexing strategies. The position requires building and scaling distributed training environments using NCCL and InfiniBand for multi-GPU and multi-node training. You will apply reinforcement learning techniques such as RLHF and RLAIF to align model behavior with human preferences and domain-specific goals. Collaboration with cross-functional teams to translate business needs into AI-driven solutions for production deployment is essential.

Primary Responsibilities:

• Develop end-to-end training and fine-tuning of Large Language Models (LLMs), including open-source and closed-source ecosystems.
• Architect and implement GraphRAG pipelines for enhanced contextual grounding.
• Design, train, and optimize semantic and dense vector embeddings for document understanding, search, and retrieval.
• Develop semantic retrieval systems with advanced document segmentation and indexing strategies.
• Build and scale distributed training environments using NCCL and InfiniBand.
• Apply reinforcement learning techniques (e.g., RLHF, RLAIF) to align model behavior.
• Collaborate with cross-functional teams to deliver AI-driven solutions.
• Comply with all company policies and directives.

Required Qualifications:

• PhD or Master's degree in computer science, Machine Learning, or related field.
• 6+ years of experience in applied AI/ML with statistics, with a solid track record of delivering production-grade models.
• Experience with Exploratory Data Analysis (EDA).
• Proficiency with PyTorch.
• Experience with LLM training and fine-tuning (e.g., GPT, LLaMA, Mistral, Qwen).
• Experience with Graph-based retrieval systems (GraphRAG, knowledge graphs).
• Experience with Embedding models (e.g., BGE, E5, SimCSE).
• Experience with Semantic search and vector databases (e.g., FAISS, Weaviate, Milvus).
• Experience with Document segmentation and preprocessing (OCR, layout parsing).
• Experience with Model fusion and ensemble techniques.
• Experience with Optimization algorithms (Bayesian, Particle Swarm, Genetic Algorithms).
• Experience with Reinforcement learning (e.g., RLHF, PPO, DPO, GRPO), Supervised Fine Tuning (SFT), LoRA, QLoRA, axolotl.
• Experience with Prompt optimization frameworks (AutoPrompt, GreaterPrompt, DSPy), GEPA.
• Experience with Hybrid NLP solutions.
• Deep knowledge and extensive experience with Machine/Deep Learning frameworks including transformer architectures, state space models, large language models, and agentic approaches.
• Knowledge of algorithms and techniques within a computational domain with emphasis on text processing.
• Deep expertise in: NLP, Fundamental machine learning, deep learning, transformer, state space-based architecture.
• Experience with Azure ML and/or AWS.
• Proven solid in Python coding, SQL and database queries, data preparation, and analysis.

At UnitedHealth Group, our mission is to help people live healthier lives and make the health system work better for everyone. We are committed to enabling and delivering equitable care that addresses health disparities and improves health outcomes.