Quantifying the performance of approximate teleportation and quantum error correction via symmetric two-PPT-extendibility

TL;DR

This paper introduces a method to quantify the performance of approximate quantum teleportation and error correction using symmetric two-PPT-extendibility, providing bounds and computational techniques for practical resource states.

Contribution

It develops a semi-definite relaxation approach to evaluate approximate teleportation and quantum error correction performance, leveraging symmetry to reduce computational complexity.

Findings

Bounds on teleportation and error correction performance for various states.

Reduction in computational cost via symmetry exploitation.

Application of bounds to specific resource states and channels.

Abstract

The ideal realization of quantum teleportation relies on having access to a maximally entangled state; however, in practice, such an ideal state is typically not available and one can instead only realize an approximate teleportation. With this in mind, we present a method to quantify the performance of approximate teleportation when using an arbitrary resource state. More specifically, after framing the task of approximate teleportation as an optimization of a simulation error over one-way local operations and classical communication (LOCC) channels, we establish a semi-definite relaxation of this optimization task by instead optimizing over the larger set of two-PPT-extendible channels. The main analytical calculations in our paper consist of exploiting the unitary covariance symmetry of the identity channel to establish a significant reduction of the computational cost of this latter optimization. Next, by exploiting known connections between approximate teleportation and quantum error correction, we also apply these concepts to establish bounds on the performance of approximate quantum error correction over a given quantum channel. Finally, we evaluate our bounds for various examples of resource states and channels.