Benchmarking Quantum Computers. Are These Devices Ready to Go Beyond Supremacy?

Simulating quantum many-body dynamics on a current digital quantum computer

Selected notes ~

+  Universal quantum computers are potentially an ideal setting for simulating many-body quantum dynamics that is out of reach for classical digital computers. We use state-of-the-art IBM quantum computers to study paradigmatic examples of condensed matter physics—we simulate the effects of disorder and interactions on quantum particle transport, as well as correlation and entanglement spreading.

Given the current stage of development, and the immense expectation from the public and physics communities, it is timely to critically assess and benchmark the state-of-the-art… By measuring a range of physical correlators, we can assess the capabilities and limitations of current quantum computers for simulating quantum dynamics.

+  Our benchmark results show that the quality of the current machines is below what is necessary for quantitatively accurate continuous-time dynamics of observables and reachable system sizes are small comparable to exact diagonalization.

+  Despite this, we are successfully able to demonstrate clear qualitative behaviour associated with localization physics and many-body interaction effects.

Source:  npj.  Smith, A., Kim, M.S., Pollmann, F. et al. Simulating quantum many-body dynamics on a current digital quantum computer. npj Quantum Inf 5, 106 (2019) doi:10.1038/s41534-019-0217-0,  Simulating quantum many-body dynamics on a current digital quantum computer…

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