Applied Research Scientist, World Model AI (Equity)

Lightfield; San Francisco (CA); On-site; USD 220,000 - 300,000; Full time

Benefits offered by this job

Competitive salary

Meaningful equity

Health insurance

3 weeks PTO

11 holidays

Paid family leave

Wednesdays WFH

Team events

401k

Commuter stipend

Lunch stipend

Job summary

Lightfield is hiring a senior applied researcher to lead world-model research for business applications. You will own projects from initial question to measurable product impact, shaping the lab’s agenda, culture and reputation as it grows.

You will work with AI engineers to translate research into production, publish benchmarks and papers, and mentor teammates. The role reports to the Chief AI Officer and offers equity and a collaborative environment.

Qualifications

• 7+ years of applied research experience in ML or NLP, in industry or academia.
• PhD or MS in Computer Science, Machine Learning or a related field, or equivalent research experience.
• Track record of research that shipped or was published: papers, open-source models, datasets or benchmarks.
• Deep hands-on experience with LLMs, including evaluation, agent design and retrieval. Post-training (SFT, RL, preference optimization) is a plus.
• Rigorous about experimental design and able to distinguish real improvements from noise.
• Strong Python skills and comfortable in production codebases (TypeScript, Node.js, PostgreSQL).
• Ability to drive ambiguous problems independently with visible results and clear communication.

Responsibilities

• Lead research projects in evaluation, benchmarks, deal prediction, simulation and self-improvement.
• Design empirical evaluations of Lightfield’s AI system using LLM-as-judge, rubric-based grading, offline replay and A/B tests.
• Build benchmarks for GTM tasks such as list building, CSV imports, mail intelligence and record updates.
• Create simulated companies with users and email/meeting streams to evaluate the end-to-end system.
• Develop techniques to improve the AI system at world, company and user levels (RL, fine-tuning).
• Model deal probability and ship as product features.
• Improve cost and quality trade-offs across the AI stack, including inference cost.
• Publish research blog posts, open benchmarks, arXiv reports and present at conferences.
• Help build a world-class research team by recruiting and mentoring teammates.

Skills

Applied ML/NLP

LLMs experience

Python

RL techniques

TypeScript

Node.js

PostgreSQL

Education

PhD in Computer Science

MS in ML/CS

Tools

PyTorch

scikit-learn

Git

Docker

Job description

Lightfield is hiring a senior applied researcher to lead world-model research for business applications. You will own projects from initial question to measurable product impact, shaping the lab’s agenda, culture and reputation as it grows.

You will work with AI engineers to translate research into production, publish benchmarks and papers, and mentor teammates. The role reports to the Chief AI Officer and offers equity and a collaborative environment.