Fail fast: techniques to probe rare events in quantum error correction

A central challenge in evaluating proposals such as the fault-tolerant qLDPC architecture introduced in Tour de Gross [1] is to predict performance in the extremely rare-failure regime required for large-scale quantum computation, where Monte Carlo simulation becomes infeasible. This talk will present the analytical and numerical techniques developed in [2] and applied in [1]. We outline three complementary techniques that together yield consistent predictions of logical error rates far below the reach of standard sampling. The focus of the talk will be on the conceptual foundations of these techniques: why they work, the conditions that govern their validity, and how they enable the evaluation of next-generation quantum LDPC codes and other architectures beyond the limits of brute-force Monte Carlo simulation.

[1] Theodore J.~Yoder, Eddie Schoute, Patrick Rall, Emily Pritchett, Jay M.~Gambetta, Andrew W.~Cross, Malcolm Carroll, and Michael E.~Beverland. ``Tour de gross: A modular quantum computer based on bivariate bicycle codes." preprint arXiv.03094 (2025).

[2] Michael E. Beverland, Malcolm Carroll, Andrew W. Cross, and Theodore J. Yoder1 ``Fail fast: techniques to probe rare events in quantum error correction." preprint arXiv.15177 (2025)