Staff+ Applied Researcher: Build AI World Models for Business

Lightfield; San Francisco (CA); Hybrid; USD 180,000 - 240,000; Full time

Benefits offered by this job

Competitive salary

Meaningful early equity

Health insurance (medical, dental, and

3 weeks of PTO

11 paid company holidays + winterbreak

3 months paid family leave

Wednesdays work from home

Regular team dinners and retreats

401k plan

Commuter and lunch stipend

Job summary

Lightfield is hiring an experienced researcher to build a Business World Model through frontier research in simulation, world modeling and self-improvement. You will own projects from conception to measurable impact, shaping the lab's agenda and reputation as it grows.

You will lead evaluations, build benchmarks, and publish open benchmarks and papers while mentoring teammates. Join a team applying ML/NLP to real-world business challenges in SF.

Qualifications

• 7+ years of applied research experience in ML or NLP, in industry or academia.
• PhD or MS in Computer Science, Machine Learning or 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, evaluation, agent design and retrieval. Post-training experience is a plus.
• Rigorous about experimental design and able to distinguish real improvements from noise.
• Strong Python and production-code comfort (TypeScript, Node.js, PostgreSQL) alongside engineers.
• Ability to drive ambiguous problems independently with visible results.
• Clear written and oral communication to technical and non-technical audiences.

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, record updates and outbound.
• Create simulated companies with users and knowledge streams to evaluate the end-to-end system.
• Develop techniques for improvement at world, company and user levels, including RL and fine-tuning.
• Model deal probability and ship as product features.
• Improve cost and quality trade-offs across the AI system, including inference cost.
• Publish research blog posts, open benchmarks, arXiv reports and papers; present at conferences.
• Help build a world-class research team by recruiting and mentoring teammates.

Skills

ML research

NLP

LLMs eval

Agent design

Retrieval

Experiment design

Python

TypeScript

Node.js

PostgreSQL

Education

MS in CS/ML

PhD preferred

Tools

Python

TypeScript

Node.js

PostgreSQL

Job description

Lightfield is hiring an experienced researcher to build a Business World Model through frontier research in simulation, world modeling and self-improvement. You will own projects from conception to measurable impact, shaping the lab's agenda and reputation as it grows.

You will lead evaluations, build benchmarks, and publish open benchmarks and papers while mentoring teammates. Join a team applying ML/NLP to real-world business challenges in SF.