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Senior AI Researcher: LLM post-training for hallucination reduction (f/m/d)

Aleph Alpha· Research
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Hybrid (Heidelberg), Hybrid (Berlin)Full-timePosted 1w ago

About the role

Senior AI Researcher focused on LLM post-training to reduce hallucinations, grounding models in evidence, and improving uncertainty estimation, calibration, and self-correction. Hybrid, Heidelberg/Berlin, full-time.

Responsibilities

  • Core Research & Development: Design, execute, and scale post-training methodologies (SFT, RL) specifically aimed at eliminating model hallucinations and making them grounded in evidence.
  • Uncertainty & Reliability: Research and implement techniques in uncertainty estimation, calibration, self-consistency, and self-correction mechanisms to enable models to identify and signal when they “don't know”.
  • Post-Training Pipelines: Build and optimize high-throughput, distributed fine-tuning and training pipelines across multi-node GPU clusters.
  • Evaluation & Benchmarking: Design and implement rigorous evaluation methods to benchmark hallucination rates, truthfulness, and reasoning accuracy.
  • Technical Ownership: Drive research projects independently from initial hypothesis to scalable production implementation and technical reports.

Qualifications

  • Hands-on experience fine-tuning or post-training LLMs using modern distributed training frameworks.
  • Track record of research or implementation in at least one of the following domains: Hallucination mitigation / truthfulness alignment / grounding in RAG; Uncertainty estimation, or out-of-distribution detection; Retrieval-Augmented Generation evaluation / alignment, refusal behavior calibration, or claim verification.
  • Strong programming skills (Python & PyTorch).

Skills

Required:Fine-tuning or post-training of LLMsHallucination mitigation / truthfulness alignment / grounding in RAGUncertainty estimation / out-of-distribution detectionPythonPyTorch
Nice to have:Retrieval-Augmented Generation evaluation / alignment / claim verification

Benefits

  • Become part of an AI revolution!
  • 30 days of paid vacation
  • Access to a variety of fitness & wellness offerings via Wellhub
  • Mental health support through nilo.health
  • Substantially subsidized company pension plan for your future security
  • Subsidized Germany-wide transportation ticket
  • Budget for additional technical equipment
  • Flexible working hours for better work-life balance and hybrid working model
  • JobRad® Bike Lease
Last updated Oct 14, 2026. Interested? Apply on the company site.

About Aleph Alpha

Sovereign AI Solutions for Enterprises and Governments by Aleph Alpha

Aleph Alpha empowers enterprises and governments with sovereign AI solutions for complex and critical processes. Secure your sovereignty, protect your data, and shape the future of AI-driven knowledge work.

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