Realizing Quantum Advantage Before Fault Tolerance
Physics Colloqium with Jay Gambetta, IBM Quantum
Abstract: Today’s quantum computers are noisy and imperfect. However, they are already accessing regimes that challenge classical computation. In this talk, I will explore whether current quantum processors can perform computations exhibiting separations over classical computing that can be rigorously validated. To do so, I will discuss how improvements in quantum hardware and integration with classical resources are not only enabling error mitigation and post-selected error correction techniques to yield verifiable quantum outputs at scales beyond exact classical verification—but are also pushing the limits of leading classical approximations. Then I will address how these experimental results can be benchmarked, highlighting the Quantum Advantage Tracker as a means of monitoring progress across three key problem types: observable estimations, variational problems, and classically verifiable problems. Finally, I will look at how hybrid classical-quantum algorithms and heterogeneous architectures are the key to scaling these advantages. Ultimately, these examples suggest there is a credible path to quantum advantage before fault tolerance
