Condensed Matter Seminar: "Fidelity of a quantum state protected by the surface code at finite temperatures"

A fundamental challenge to quantum information processing is to protect information from the detrimental effects of the environment. A milestone in addressing this problem was the development of the theory of quantum error correction (QEC). In this work, we build upon previous studies in order to evaluate the fidelity of a quantum state protected by one of the best QEC codes: the surface code. We discuss the protection of a quantum state for different spectral functions, bath temperatures and QEC cycles times. Analytical results are supported by finite size scaling analyses of Monte Carlo and exact diagonalization of finite lattices. Our results demonstrate a finite threshold that explicitly depends on the bath mediated qubit-qubit interaction range and temperature of the bath.