Senior LLM Engineer — Quantum AI & Model Optimization

Multiverse Computing; Barcelona; On-site; EUR 90,000 - 130,000; Full time

Job summary

Multiverse Computing in Spain is seeking a Senior LLM Engineer to join our Research team. You will work across the full model lifecycle: data, distributed training, post-training, compression, evaluation and efficient inference.

Our past work includes compressing and healing open-weight models, post-training with SFT, RL and distillation, multimodal training, knowledge editing, and building our family of models. We value strong fundamentals and publish papers when appropriate.

Qualifications

• Master's or PhD in CS, AI, Mathematics, Physics or related field.
• Senior: 4+ years of hands-on experience training or post-training transformer models.
• Strong PyTorch, low-level model code and parallelism.
• Experience with distributed training (FSDP, DeepSpeed or Megatron-LM; data, tensor, pipeline and expert parallelism) on multi-node clusters.
• Fluent English communication.

Responsibilities

• Train and post-train LLMs and multimodal models on multi-node GPU clusters using SFT, preference optimisation, RL (e.g. GRPO), and on-policy and offline distillation.
• Design compression techniques (quantization, pruning, quantization-aware training, quantum-inspired tensor-network methods) and healing recipes that recover the quality of compressed models.
• Build RL environments, reward functions and verifiers for reasoning, coding and agentic tasks, and extend RL methods to world models and Physical AI.
• Research and prototype post-transformer and hybrid architectures (state-space models, linear attention, MoE), from small-scale ablations to scaling recipes.
• Build data pipelines for curation, filtering, deduplication and large-scale synthetic data generation.
• Design rigorous ablations and evaluations on current benchmark suites (reasoning, coding, long-context, instruction following, agentic) as well as internal evals.
• Port and optimise models for inference on various accelerators and edge chips, profiling latency, memory and throughput.
• Write up experiments and results as internal reports and, where relevant, papers and open-source releases.
• Review code, mentor teammates, and follow and bring in the latest research.

Skills

PyTorch

Distributed training

Deep learning

English fluency

SFT RL

Education

Master's or PhD in CS/AI

Tools

Megatron-LM

DeepSpeed

Kubernetes

Slurm

Job description

Multiverse Computing in Spain is seeking a Senior LLM Engineer to join our Research team. You will work across the full model lifecycle: data, distributed training, post-training, compression, evaluation and efficient inference.

Our past work includes compressing and healing open-weight models, post-training with SFT, RL and distillation, multimodal training, knowledge editing, and building our family of models. We value strong fundamentals and publish papers when appropriate.