Protection of noisy multipartite entangled states of superconducting qubits via universally robust dynamical decoupling schemes

TL;DR

This paper demonstrates that the universally robust dynamical decoupling (URDD) sequence effectively preserves multipartite entangled states on a cloud-based quantum computer, with performance enhancements from phase randomization techniques.

Contribution

The study introduces and experimentally validates the use of URDD combined with phase randomization methods to protect multipartite entanglement against noise on IBM quantum hardware.

Findings

URDD successfully preserves multipartite entangled states.

Adding phase randomization improves protection performance.

Experimental validation on IBM quantum platform.

Abstract

We demonstrate the efficacy of the universally robust dynamical decoupling (URDD) sequence to preserve multipartite maximally entangled quantum states on a cloud based quantum computer via the IBM platform. URDD is a technique that can compensate for experimental errors and simultaneously protect the state against environmental noise. To further improve the performance of the URDD sequence, phase randomization (PR) as well as correlated phase randomization (CPR) techniques are added to the basic URDD sequence. The performance of the URDD sequence is quantified by measuring the entanglement in several noisy entangled states (two-qubit triplet state, three-qubit GHZ state, four-qubit GHZ state and four-qubit cluster state) at several time points. Our experimental results demonstrate that the URDD sequence is successfully able to protect noisy multipartite entangled states and its performance is substantially improved by adding the phase randomization and correlated phase randomization sequences.