I am interested in learning more about the following: would it be possible for me to simulate a molecule consisting of copper ions through a quantum circuit?

And if so, can that circuit allow me to measure the decoherence time of that molecule?

I know it's an open-ended question, so any books, research papers, etc, would be much appreciated it.

  • $\begingroup$ Can you please explain what you mean by the "decoherence time of a molecule"? $\endgroup$ Aug 16, 2020 at 18:32

1 Answer 1


Since Google is one of, if not the, industry leaders in molecular simulation with quantum computers, their published work is a reasonable benchmark for what's presently within reach. As you probably know, a few years ago Google reported (commentary) successful electronic structure calculations for a Hydrogen atom, favoring the variational quantum eigensolver approach. A lot has happened since then, but I haven't noticed much recently from Google on VQE (though others are still actively working on VQE).

The most recent paper from Google uses phase estimation performed on a quantum walk to simulate FeMoco. This simulation requires $8 \times 10^{10}$ Toffoli gates (best case) and about three million qubitweeks of state distillation (a 700x improvement over the previous approach).

This is an unsatisfactory answer, but obviously the complexity of Copper ions lies somewhere between a Hydrogen atom (feasible) and FeMoco (not yet feasible), though I'm not sure how to quantify where it falls in that spectrum. The recent Google paper has an up-to-date list of references for further reading on the topic.


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