Drimva

Epsilon Health

Research Engineer / Research Scientist, Post-Training & Reinforcement Learning

San Francisco, CA · On-site · Full-time · Posted Aug 31, 2026

About the job

Develops post-training and reinforcement learning methods for multimodal medical AI to produce accurate, reliable radiology reports from medical images.

What you'll do

  • Develop post-training methods, reward models, and multimodal reasoning capabilities, and explore agentic tool use and inference-time optimization.
  • Own research from experimental design through distributed training and evaluation, with deployment handoff.
  • Create rigorous clinical evaluations and contribute original research and technical insights.

What they ask for

  • Expertise in reinforcement learning, language model post-training, or multimodal machine learning.
  • Demonstrated ability to develop, train, or improve state-of-the-art machine learning models.
  • Strong understanding of post-training techniques, including reinforcement learning, reward modeling, and preference optimization.
  • Experience with large-scale distributed training using PyTorch or JAX.

Nice to have

  • Publications at leading ML conferences such as NeurIPS, ICML, ICLR, CVPR, or ACL.
  • Experience with RL algorithms, reward models or RLHF, large-scale RL infrastructure, multimodal reasoning, inference-time optimization, medical imaging, or reliability evaluation.

Tools

PyTorch, JAX, GRPO, DAPO, vLLM, SGLang, verl, TRL

AI focus

Post-training and reinforcement learning for multimodal medical AI, including reward modeling, clinical reasoning, agentic tool use, and inference-time optimization.

Model-written summary · the original posting is authoritative

First seen Oct 29, 2026 · Last verified Nov 5, 2026 (UTC)