# Experimental realization of nondestructive discrimination of Bell states using a five-qubit quantum computer

## TL;DR

This paper demonstrates the nondestructive discrimination of Bell states using a five-qubit superconducting quantum computer, confirming the feasibility and high fidelity of such measurements on cloud-based quantum hardware.

## Contribution

It extends previous NMR-based experiments to superconducting qubits, showing nondestructive Bell state measurement on a scalable quantum platform.

## Key findings

- Bell states can be constructed and measured nondestructively with high fidelity.
- Comparison shows similar results to earlier NMR experiments.
- Gate errors need reduction for scalable quantum computing.

## Abstract

A scheme for distributed quantum measurement that allows nondestructive or indirect Bell measurement was proposed by Gupta et al., (Int. J. Quant. Infor. \textbf{5} (2007) 627) and subsequently realized experimentally using an NMR-based three-qubit quantum computer by Samal et al., (J. Phys. B, \textbf{43} (2010) 095508). In the present work, a similar experiment is performed using the five-qubit super-conductivity-based quantum computer, which has been recently placed in cloud by IBM Corporation. The experiment confirmed that the Bell state can be constructed and measured in a nondestructive manner with a reasonably high fidelity. A comparison of the outcomes of this study and the results obtained earlier in the NMR-based experiment has also been performed. The study indicates that to make a scalable SQUID-based computer, errors by the gates (in the present technology) have to be reduced considerably.