# Benchmarking highly entangled states on a 60-atom analog quantum simulator

**Authors:** Adam L. Shaw, Zhuo Chen, Joonhee Choi, Daniel K. Mark, Pascal Scholl, Ran Finkelstein, Andreas Elben, Soonwon Choi, Manuel Endres  
**arXiv:** [2308.07914](https://arxiv.org/abs/2308.07914)  
**Date:** 2023-08-15  
**Summary page:** https://www.summarizepaper.com/en/arxiv-id/2308.07914v1/

## Key points

- In the realm of quantum computing, classical computers are forced to make approximations to accurately represent highly entangled quantum states.
- Challenges exist in comparing fidelity between quantum and classical systems, especially for analog quantum devices.
- A study by Adam L. Shaw, Zhuo Chen, Joonhee Choi, Daniel K. Mark, Pascal Scholl, Ran Finkelstein, Andreas Elben, Soonwon Choi, and Manuel Endres used a 60-atom analog Rydberg quantum simulator to push boundaries into a high entanglement entropy regime where exact classical simulation is impractical.
- The team developed an estimator for experimental mixed-state entanglement through extrapolation from comparisons against various approximate classical algorithms with varying entanglement limits.
- The experiment proved competitive with state-of-the-art digital quantum devices engaged in random circuit evolution.
- Only one newly introduced algorithm was able to keep pace with the experiment on the classical hardware utilized by the team.
- These results open new avenues for evaluating the performance of analog and digital quantum devices operating beyond-classically-exact regimes.
- The study highlights the evolving disparity between quantum and classical systems while showcasing the potential of analog quantum simulators in advancing entanglement studies.

## Summary

In the realm of quantum computing, a competitive landscape has emerged where classical computers are forced to make approximations in order to accurately represent highly entangled quantum states. This transition into a beyond-classically-exact regime has posed challenges in comparing fidelity between quantum and classical systems, particularly when it comes to analog quantum devices. The ability to estimate the actual entanglement content of experiments has remained a puzzle yet to be solved. In a groundbreaking study, Adam L. Shaw, Zhuo Chen, Joonhee Choi, Daniel K. Mark, Pascal Scholl, Ran Finkelstein, Andreas Elben, Soonwon Choi, and Manuel Endres have conducted  and  using a 60-atom analog Rydberg quantum simulator. Their research pushes the boundaries into a high entanglement entropy regime where exact classical simulation becomes impractical. The  employed by the team involves extrapolation from comparisons against numerous approximate classical algorithms with varying entanglement limits. Through this methodical approach, they were able to develop and demonstrate an estimator for experimental mixed-state entanglement. Surprisingly, their experiment proved to be competitive with state-of-the-art digital quantum devices engaged in random circuit evolution. Furthermore, the researchers compared the experimental fidelity achieved in their study against various approximate classical algorithms. Intriguingly, only one newly introduced algorithm was able to keep pace with the experiment on the classical hardware utilized by the team. These groundbreaking results open up new avenues for evaluating the performance of both analog and digital quantum devices operating in the beyond-classically-exact regime. They shed light on the evolving disparity between quantum and classical systems while showcasing the potential of analog quantum simulators in pushing the boundaries of entanglement studies. The collaborative effort of these researchers marks a significant advancement in our understanding of highly entangled states and sets a new standard for future research in this field.