Robust analog quantum simulators by quantum error-detecting codes: Part II

Achieving noise resilience is an outstanding challenge in Hamiltonian-based quantum computation. To this end, energy-gap protection provides a promising approach, where the desired quantum dynamics are encoded into the ground space of a penalty Hamiltonian that suppresses unwanted noise processes. However, existing approaches either explicitly require high-weight penalty terms that are not directly accessible in current hardware, or utilize non-commuting 2-local Hamiltonians, which typically leads to an exponentially small energy gap. In this work, we introduce a general recipe for designing error-resilient Hamiltonian simulations, utilizing an excited encoding subspace stabilized by solely 2-local commuting Hamiltonians.

Part II of this talk focuses on the implementation of universal 2-local logical interactions via 2-local physical terms. This is realized via a family of quantum error-detecting codes (QEDC) constructed from the block composition of the QEDC introduced in Part I. Specifically, we design a novel class of perturbative gadgets that is compatible with our error-suppression framework. We illustrate the power of our approach by its application to simulating many-body spin models.