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

AlephalphaHeidelberg🇩🇪GermanyPosted 14 Oct 2026

Why This Role Stands Out

Advance your career in AI research by developing cutting-edge techniques to enhance LLM reliability and trustworthiness at a leading European foundation model developer. You'll thrive here if you're passionate about pushing the boundaries of post-training methodologies and contributing to impactful, human-centric AI solutions. Apply to join a dynamic team with access to significant GPU resources and a hybrid work environment.

Quick Overview

Seniority
Mid Senior
Employment type
Full Time
Work mode
Hybrid
Location
Heidelberg, Germany
Posted
12 hours ago
LLMMental HealthPyTorchPython

Job Description

Who we are

Aleph Alpha’s mission is to deliver sovereign, human-centric AI to governmental institutions and large enterprises. To that end, we deliver category-defining AI innovation that enables open, accessible, and trustworthy deployment of GenAI in industrial applications. Our organization develops foundational models and next-generation methods that make it easy and affordable for Aleph Alpha’s customers to increase productivity in development, engineering, logistics, and manufacturing processes.

About the role

We are looking for a (Senior) AI Researcher to join our hallucination reduction capability team to push the boundaries in LLM post-training (SFT and RL).

We're one of the few places in Europe training foundation models from scratch. You will be part of a team of (senior) researchers and PhD interns doing cutting-edge research across pre-, mid- and post-training, grounding and specialized models with hundreds of GPUs at our disposal.

What will you do

  • 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).

Compensation and 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