Research

I work on post-training and evaluation of LLMs at Google DeepMind, with a focus on agents operating in open-ended environments that have no single best answer. My work includes scaling reinforcement-learning data for scientific tasks and building evaluation benchmarks for scientific agents.

Before moving into machine learning, I completed a PhD in physics at Berkeley, where I helped formulate and prove the Quantum Null Energy Condition. I later worked at the Perimeter Institute as an It from Qubit fellow, studying information transfer in evaporating black holes.

Machine Learning

Gemini Team, Google (including Z. Fisher). Gemini 2.5: Pushing the Frontier with Advanced Reasoning, Multimodality, Long Context, and Next Generation Agentic Capabilities. arXiv:2507.06261 (2025).

Gemini Team, Google (including Z. Fisher). Gemini 1.5: Unlocking Multimodal Understanding Across Millions of Tokens of Context. arXiv:2403.05530 (2024).

B. Gunel, J.B. Wendt, J. Xie, Z. Fisher et al. STRUM-LLM: Attributed and Structured Contrastive Summarization. arXiv:2403.19710 (2024).

Y. Sheng, S. Gandhe, B. Kanagal, Z. Fisher et al. Measuring an LLM’s Proficiency at Using APIs: A Query Generation Strategy. KDD-ADS (2024).

R. Aksitov, S. Miryoosefi, Z. Fisher et al. ReST meets ReAct: Self-Improvement for Multi-Step Reasoning LLM Agent. arXiv:2312.10003 (2023).

L. Vilnis, Z. Fisher, B. Kanagal, P. Murray, S. Sanghai. Impakt: A Dataset for Open-Schema Knowledge Base Construction. arXiv:2212.10770 (2022).

S. Ontanon, J. Ainslie, Z. Fisher, V. Cvicek. Making Transformers Solve Compositional Tasks. ACL (2022).

S. Ontanon, J. Ainslie, V. Cvicek, Z. Fisher. LogicInference: A New Dataset for Teaching Logical Inference to Seq2Seq Models. arXiv:2203.15099 (2022).

J. Ainslie, S. Ontanon, C. Alberti, V. Cvicek, Z. Fisher et al. ETC: Encoding Long and Structured Inputs in Transformers. EMNLP (2020).

Physics

H.Z. Chen, Z. Fisher, J. Hernandez, R.C. Myers, S.M. Ruan. Evaporating Black Holes Coupled to a Thermal Bath. JHEP 2021 (1), 65.

H.Z. Chen, Z. Fisher, J. Hernandez, R.C. Myers, S.M. Ruan. Information Flow in Black Hole Evaporation. JHEP 2020 (3), 152.

Z. Fisher, C.J. Mogni. A Semiclassical, Entropic Proof of a Weak Gravity Conjecture. arXiv:1706.08257 (2017).

R. Bousso, Z. Fisher, S. Leichenauer, A. Wall. Quantum Focusing Conjecture. Phys. Rev. D 93, 064044 (2016).

R. Bousso, Z. Fisher, J. Koeller, S. Leichenauer, A. Wall. Proof of the Quantum Null Energy Condition. Phys. Rev. D 93, 024017 (2016). Editors’ Suggestion.

R. Bousso, H. Casini, Z. Fisher, J. Maldacena. Entropy on a Null Surface for Interacting Quantum Field Theories and the Bousso Bound. Phys. Rev. D 91, 084030 (2015).

R. Bousso, H. Casini, Z. Fisher, J. Maldacena. Proof of a Quantum Bousso Bound. Phys. Rev. D 90, 044002 (2014).

C. Sun, Z. Fisher, C. Pappas, D. Robin. Pulsed Multipole Injection for the ALS Upgrade. Proceedings of IPAC (2010), 2642.

Patents and Disclosures

A. Sadr, T. Yu, D. Li, Z. Fisher et al. Artificial Intelligence Generated Badges for Search. U.S. Patent Application 18/636,844 (2024).

H. Wu, Z. Fisher et al. Automated Optimization of Structured Large Language Model Prompts via Iterative Evaluation. Technical Disclosure Commons (2026).

Zach Fisher