Handshake AI is seeking a PhD Student Researcher to work on novel RLHF/GRPO pipelines, instruction-following refinements, reasoning-trace supervision, multilingual/long-horizon/domain-specific benchmarks, automatic vs. human preference studies, robustness diagnostics, active-learning loops, data value estimation, synthetic data generation, and low-resource fine-tuning strategies. The goal is to produce an archive-ready manuscript or top-tier conference submission.