Justus C. Will
Also known as Justus Will
Justus C. Will is a PhD student in machine learning at the University of California, Irvine, working on climate-model emulation, neural data compression and faster decoding for language models. After degrees in mathematics and computer science at TU Kaiserslautern, he worked there as a research assistant in Marius Kloft's Machine Learning Group on tensor completion. He began his PhD at UC Irvine in 2023, advised by Stephan Mandt, and was an author of ClimSim, a dataset of 5.7 billion input-output pairs for training machine-learning climate emulators that won an Outstanding Paper Award at NeurIPS 2023. In 2025, his paper with Yibo Yang and Mandt on progressive image compression with universally quantized diffusion models was selected as an oral at ICLR, and in 2026 he presented Parallel Token Prediction for language models at the same conference.
Timeline
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2017–2022
Degrees at TU Kaiserslautern
He studies mathematics and computer science at TU Kaiserslautern, earning two bachelor's degrees and then an M.Sc. in mathematics in 2022, with a semester abroad at Lund University in Sweden.
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2019–2022
Tensor completion in Kaiserslautern
From October 2019 to May 2020, he is a research assistant at the German Research Center for Artificial Intelligence (DFKI), where he develops an evolutionary algorithm that optimizes the topology and hyperparameters of convolutional networks. From October 2020 to December 2022, he is a research assistant in Marius Kloft's Machine Learning Group at TU Kaiserslautern, where he develops a tensor completion framework for sparse tabular data.
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2023
A PhD at UC Irvine
In 2023, he begins a Ph.D. in computer science at the University of California, Irvine, advised by Stephan Mandt.
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2023
ClimSim wins a NeurIPS award
He is an author of ClimSim, a dataset of 5.7 billion pairs of input and output vectors for training machine-learning emulators of high-resolution climate physics, developed by a consortium of climate scientists and ML researchers. The paper receives an Outstanding Paper Award in the Datasets and Benchmarks Track at NeurIPS 2023.
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2025
ClimSim-Online in JMLR
In 2025, the Journal of Machine Learning Research publishes ClimSim-Online, on which he is an author. It extends ClimSim with an end-to-end workflow and a containerized pipeline for coupling ML models into operational climate simulators for hybrid testing.
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2025
Progressive compression at ICLR
In 2025, he and Yibo Yang, with Stephan Mandt, present Progressive Compression with Universally Quantized Diffusion Models, selected as an oral at ICLR. The paper proposes a diffusion model with uniform noise in the forward process, whose negative ELBO corresponds to the end-to-end compression cost under universal quantization.
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2026
Parallel Token Prediction at ICLR
In 2026, he coauthors Parallel Token Prediction for Language Models with Felix Draxler, Stephan Mandt and others, presented at ICLR in April 2026. The method predicts several tokens in a single model call by moving the source of randomness from post-hoc sampling to random input variables.
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As of October 2026
PhD student at UC Irvine
He is a PhD student at the University of California, Irvine, advised by Stephan Mandt, with research on deep generative models, neural data compression and machine learning for climate science.
Career
- 2020–2022University of KaiserslauternResearch Assistant
- 2019–2020DFKIResearch Assistant
Education
- From 2023University of California, IrvinePhD
- 2022University of KaiserslauternBachelor's degrees in Mathematics and Computer Science; M.Sc. in Mathematics
Sources and credits
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- Justus Will
- Justus Will - Machine Learning Group, TU Kaiserslautern
- #NeurIPS2023 outstanding papers - AIhub
- ClimSim: A large multi-scale dataset for hybrid physics-ML climate emulation
- ClimSim-Online: A Large Multi-scale Dataset and Framework for Hybrid ML-physics Climate Emulation
- Progressive Compression with Universally Quantized Diffusion Models
- ICLR 2025 Oral: Progressive Compression with Universally Quantized Diffusion Models
- Parallel Token Prediction for Language Models
- ICLR Poster Parallel Token Prediction for Language Models


