Quantum computing in the NISQ era


Concentrated efforts all around the globe are pursuing the development of viable quantum technologies. However, the technological challenges are immense, and it may still take some time before the first fault-tolerant quantum computers may become available for practical applications. Thus, it is of instrumental importance to not only build a quantum literate workforce, but to also ensure investments are made in realistic and societally beneficial avenues for development.

Despite the fact that the first demonstrations of quantum advantage have been published, currently available hardware is still prone to noise. Thus, it has been argued that we are in the era of noisy-intermediate scale quantum (NISQ) technologies. For instance, the DWave quantum annealer promises to deliver scalability beyond current classical hardware limitations. However, exploiting NISQ technologies often requires a different mathematical modeling framework. For instance, the D-Wave quantum annealer accepts an Ising spin-glass instance as its input and outputs solutions encoded in spin configurations. High-quality solutions are expected to be computed by these devices in a reasonable time, even for problems of the size which already bear practical relevance (currently, up to 5000 variables on a sparse graph). More importantly, a NISQ computer may not (yet) be able to outperform classical computers, however seeking and demonstrating amendable applications provides the instrumental guiding principle for the development of purpose-specific devices with genuine quantum advantage.

Introductory reading:

  • Quantum annealing in the NISQ era: railway conflict management
    Krzysztof Domino, Mátyás Koniorczyk, Krzysztof Krawiec, Konrad Jałowiecki, Sebastian Deffner, and Bartłomiej Gardas
    Entropy 25, 191 (2023) [arXiv:2112.03674]