Recorded 08 November 2023. Thomas Schuster of the California Institute of Technology presents "Noise, complexity, and information dynamics in quantum circuits" at IPAM's Many-body Quantum Systems via Classical and Quantum Computation Workshop. Abstract: I will discuss two recent works that leverage ideas from quantum information dynamics to understand the impact of noise on large-scale quantum systems. First, I will introduce a framework based on information dynamics to describe how noise propagates in ergodic many-body quantum systems. Our framework yields immediate predictions for popular benchmarking protocols involving time-reversal, and provides a potential explanation for recent NMR experiments on ~100s of interacting quantum spins. Second, in a more rigorous context, I will provide a polynomial-time classical algorithm for simulating expectation values in almost any noisy quantum circuit. Our algorithm is provably efficient, and extends recent results on noisy random circuit sampling to a much more general setting. As a corollary, we establish that almost any quantum experiment that provides an exponential speed-up over classical computation must fail in the presence of a noise rate greater than ~1/n, where n is the number of qubits. Learn more online at: https://www.ipam.ucla.edu/programs/workshops/workshop-iii-many-body-quantum-systems-via-classical-and-quantum-computation/