Q2B25 Paris | Olivier Ezratty, Academic, Co Founder, Free Electron, EPITA, Quantum Energy Initiative

Olivier Ezratty, co-founder of the Quantum Energy Initiative, presents a talk on the energetic challenges of fault-tolerant quantum computing (FTQC). He emphasizes the need to consider energy consumption as a key factor in the development of quantum computers, drawing parallels with the AI industry’s energy issues. He defines two types of energetic quantum advantage: comparative (when quantum outperforms classical) and acceptability (when quantum enables tasks impossible classically, but energy consumption must be acceptable). He breaks down energy consumption into electronics, cryogenics, and classical computing, highlighting that classical computing for error correction and compilation will be a significant energy cost. He discusses the impact of error correction overhead, citing Google’s Willow chip as an example, and the need for interconnects when scaling to thousands of logical qubits. He presents resource estimates from DARPA and JQI, showing that some quantum algorithms may require prohibitive computing times. He introduces an EFP framework (Energy, Footprint, Power) for system design. He compares projected power consumption of quantum computers from various vendors to existing HPC systems, noting that some, like Xanadu, are currently too high to be acceptable. He argues that energetics is intertwined with economics, and that economies of scale are needed to reduce costs. He concludes by emphasizing the need for a holistic, interdisciplinary approach to design energy-efficient quantum systems.