The ‘quantum utility’ era
During the next three years, it is highly probable that noisy intermediate-scale quantum (NISQ) computers will continue to dominate the field, providing opportunities for all organisations to build awareness and perform experiments. An example is IBM’s 127-qubit ‘Eagle’ processor, which, according to IBM, is its first quantum processor whose scale makes it impossible for a classical computer to reliably simulate.6
NISQ computers allow organisations to experiment with new algorithms and approaches to demonstrate solutions for complex but not insurmountable problems, such as optimisation, simulation and machine learning. However, NISQ systems typically have relatively modest numbers of qubits, and are still impacted by noise and decoherence, which can interrupt calculations before they complete.
In this era, although we may see some limited advantages for quantum computers, it is likely that classical computers will still be able to compete in key domains — albeit only the most powerful existing digital supercomputers.
The ‘quantum advantage’ era
Within 5 to 10 years, it is possible that the performance of quantum computers will begin to stretch significantly ahead of classical computers. For example, more sophisticated chip architectures might extend the capabilities of qubits and enable greater algorithmic complexity. In this case, we may see quantum computers solving problems that would be impractical to run on classical computers or which would take an unreasonable amount of time. These may include simulating many-particle quantum systems to aid materials or drug discovery, or running Grover’s algorithm to significantly speed up unstructured searches.
The ‘quantum supremacy’ era
It is plausible that, within 10 to 20 years, when quantum computers are reliably noise-free or automatically error-correcting, they will have sufficient qubits, and both hardware and software sophistication to run algorithms or simulations that would be impossible to execute on classical computers. It is in this transformational level that truly disruptive impacts may occur.