Staff Research Scientist – Reinforcement Learning

Job not on LinkedIn

🕒 July 3

🏄 California – Remote

🏄 California – Remote

💵 $200k - $250k / year

⏰ Full Time

🔴 Lead

🧬 Research Scientist

🦅 H1B Visa Sponsor

This company has sponsored H1B visas in the past.

👻 Ghost score 36%

What it means: how likely this posting is sitting open without active hiring.How to read it: 60% or higher means we think this is a ghost. Lower scores are less of a worry.How we score it: age, reposts, open roles vs team size, how fast jobs close, and whether pay is listed.Fine print: an estimate from public data, not a judgment of the company. Real jobs can score high, so treat it as a hint, not a fact.

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Thermo Fisher Scientific

WebsiteLinkedInAll Job Openings

10,000+ employees

🏥 Healthcare

💼 Consulting

📦 Logistics

Healthcare • Consulting • Logistics

Thermo Fisher Scientific is a leading global supplier of scientific instrumentation, reagents and consumables, and software services. They support the life sciences, healthcare, and analytical chemistry sectors by providing robust solutions for laboratory research and production processes. Their innovative products and services encompass a range of applications, including diagnostics, lab workflow automation, and drug discovery.

📋 Description

• Design simulation environments and digital twins for enterprise workflows • Post-train LLM agents using RLHF, DPO, GRPO, PPO, and emerging methods • Build pipelines that convert human-labeled traces and verifiable signals into training data • Architect multi-turn, tool-using agents with closed learning loops • Design reward functions and verifiers that resist reward hacking and reflect real task outcomes • Set the technical bar across the team — architecture, code review, engineering standards • Mentor researchers and engineers; drive technical direction through influence • Translate research into production; contribute to publications

🎯 Requirements

• 7+ years in ML/AI research or engineering; 3+ years at senior/staff level • MS or PhD in Computer Science, Machine Learning, or related field (or equivalent) • 5+ years hands-on RL — environment design, reward engineering, policy optimization — with at least one production deployment LLM Post-Training • 3+ years fine-tuning LLMs with hands-on RL post-training (RLHF, DPO, GRPO, PPO) • Expert-level implementation of RLHF pipelines, reward modeling (Bradley-Terry), DPO, and KTO • Strong Python and software engineering skills — comfortable building production pipelines, not just notebooks • Deep expertise in MDPs, policy gradient methods (PPO, SAC), and temporal difference learning • Working knowledge of modern post-training and rollout-serving libraries (TRL, veRL, OpenRLHF, SkyRL)

🏖️ Benefits

• Health insurance • 401(k) matching • Flexible work hours • Paid time off • Remote work options