Locality and parameter tradeoffs for quantum codes

Title: Locality and parameter tradeoffs for quantum codes

Abstract: Quantum (error-correcting) codes protect from noise the delicate entanglement of quantum states that distinguishes quantum computers from classical computers. In practice, local interactions — interactions between nearby qubits — are easier to implement than non-local ones, but constraining quantum codes to local interactions limits their quality. For example, the seminal Bravyi-Poulin-Terhal (BPT) bound states that a quantum code with only local interations in two dimensions must satisfy kd^2<=O(n), where n,k,d are the number physical qubits, number of logical qubits, and distance of the code, respectively.In this talk, I will discuss how much “nonlocality” is needed to implement quantum codes beyond the BPT bound. Our works establish tight tradeoffs between the amount of nonlocality and the parameters of quantum codes, proving no-go results and showing matching code constructions. This talk will not assume prior background in quantum computing.