Researchers set benchmark to determine achievement of quantum computing

Researchers at Pacific Northwest National Laboratory (PNNL) have set a mark that a quantum system would need to surpass to establish quantum supremacy in the realm of chemistry.

That’s because the fastest classical computers available today are getting better and better at simulating what a quantum computer will eventually be expected to do. To prove itself in the real world, a quantum computer will need to be able to outdo what a fast supercomputer can do. And that’s where the PNNL-led team have set a benchmark for quantum computers to beat.

At 113 electrons, the recent benchmark simulation is the largest quantum system ever simulated at this precise level of accuracy using a classical computer. Working with collaborators in Hungary and the Czech Republic, the PNNL team set the benchmark by simulating the structure of an important chemical structure in nitrogenase, an enzyme that converts nitrogen in the atmosphere into usable fertilizer for plants. The enzyme is the subject of intense study because it may hold to key to producing enough food to feed an ever-growing global population.

Understanding how this enzyme is able to break the strong nitrogen triple bond, while expending very little energy, could be key to new catalyst design, eventually providing abundant fertilizer currently produced using a chemical process requiring large energy inputs.

Until a full-scale quantum computer is available, the PNNL team worked with Microsoft experts to develop a bridge between current digital computers and what comes next. The workflow takes advantage of what classical computers do well now, while using the current capabilities of quantum computing to describe chemical transformations relevant to industrial processes such as energy generation and energy storage. (

More information:

 Jiří Brabec, et al. Massively parallel quantum chemical density matrix renormalization group method. arXiv:2001.04890v1 [physics.chem-ph]:

Nicholas P. Bauman et al. Downfolding of many-body Hamiltonians using active-space models: Extension of the sub-system embedding sub-algebras approach to unitary coupled cluster formalisms, The Journal of Chemical Physics (2019). DOI: 10.1063/1.5094643

Nicholas P. Bauman et al. Quantum simulations of excited states with active-space downfolded Hamiltonians, The Journal of Chemical Physics(2019). DOI: 10.1063/1.5128103

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