Recovery algorithms for Clifford Hayden-Preskill problem

TL;DR

This paper introduces deterministic recovery algorithms for the Hayden-Preskill problem using Clifford dynamics, leveraging Bell measurements and feedback, with implications for quantum error correction and many-body quantum systems.

Contribution

It presents the first simple, deterministic recovery algorithms for Clifford-based Hayden-Preskill problems, connecting operator growth with recovery fidelity and extending to fault-tolerant many-body teleportation.

Findings

Recovery algorithms achieve high fidelity with Clifford unitaries.

Feedback operations depend on operator growth analysis.

Algorithms relate out-of-time order correlators to Wigner functions.

Abstract

The Hayden-Preskill recovery problem has provided useful insights on physics of quantum black holes as well as dynamics in quantum many-body systems from the viewpoint of quantum error-correcting codes. While finding an efficient universal information recovery procedure seems challenging, some interesting classes of dynamical systems may admit efficient recovery algorithms. Here we present simple deterministic recovery algorithms for the Hayden-Preskill problem when its unitary dynamics is given by a Clifford operator. The algorithms utilize generalized Bell measurements and apply feedback operations based on the measurement result. The recovery fidelity and the necessary feedback operation can be found by analyzing the operator growth. These algorithms can also serve as a decoding strategy for entanglement-assisted quantum error-correcting codes (EAQECCs). We also present a version of recovery algorithms with local Pauli basis measurements, which can be viewed as a many-body generalization of quantum teleportation with fault-tolerance. A certain relation between out-of-time order correlation functions and discrete Wigner functions is also discussed, which may be of independent interest.