Data Reduction Physicist

• Design next-generation data structures that push the limits of data reduction while preserving physics performance and analysis flexibility.
• Ensure all formats are accelerator-native (e.g., structure-of-arrays, SoA) and optimised for high-throughput GPU processing.
• Build an end-to-end framework to rigorously quantify the impact of lossy compression, with clear metrics, reference analyses, and automated regression tests.
• Benchmark compression/decompression under realistic workloads: CPU/GPU cost, I/O throughput, memory footprint, and latency.
• Advance lossless compression, leveraging R³-reconstructed objects and pioneering AI/ML techniques.
• Improve raw data structure to achieve higher compressibility and faster data access.

• Demonstrated contributions to trigger and/or reconstruction in HEP (or comparable high-throughput scientific software).
• Practical understanding of of end-to-end HEP experiment operations, from detector readout to reconstruction, calibrations, datasets, and final physics results.
• Experience working in a large international collaboration (code review, CI/CD, documentation) is a plus.
• Knowledge with LHC experiments and their data formats is a plus.
• Expertise in data compression techniques is a plus. (lossless and/or lossy).
• Experience applying AI/ML methods (e.g., autoencoders) to data reduction is a plus.
• Proficiency in GPU programming and heterogeneous computing is a plus.

Skills

• High proficiency in C++, Python, and ROOT.
• Solid understanding of event reconstruction, including calibrations and commonly used data formats in HEP.
• Spoken and written English, with a commitment to learn French.

Eligibility criteria:

• You are a national of a CERN Member or Associate Member State.
• You have a professional background in Physics (or a related field) and have either:

• a Master's degree with 2 to 6 years of post-graduation professional experience;
• or a PhD with no more than 3 years of post-graduation professional experience.

• You have never had a CERN fellow or graduate contract before., Computing engineer, radiofrequency engineer, process operator in cryogenics, web developer, mechanical engineer, administrative assistant, system administrator, power electronics engineer, scientific writer, applied physicist and many more

Desired degree disciplines/class From apprenticeship to PhD in a wide variety of domains

• A monthly stipend between 6372-7004 Swiss Francs per month (tax free) depending on your degree.
• 30 days of paid leave per year plus 2 weeks annual closure.
• Coverage by CERN's comprehensive health insurance scheme (for yourself, your spouse and children), and membership of the CERN Pension Fund.
• Family, child and infant monthly allowances depending on your individual circumstances.
• A relocation package (installation grant and travel expenses) depending on your individual circumstances.
• Possibility to extend your contract up to 36 months.
• On-the-job and formal training including language classes.

Imagine taking part in the largest scientific experiment in the world. CERN needs more than physicists and engineers - if you're a student, a graduate, just starting your career or an experienced professional, whatever your field of expertise, CERN could be your next opportunity.