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

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 https://wellhub.com/de-de/ - Mental health support through nilo.health http://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® https://www.jobrad.org/ Bike Lease