The term “quantum advantage” can refer to the experimental demonstration of a quantum algorithm solving a real-world problem on a quantum computer faster than any classical algorithm running on any classical computer. Because quantum computing terminology is not standardized, the term may also be applied to theoretical speedups – those that have not been demonstrated experimentally – as well as to problems with no known real-world utility.
The promise of such computational advantages for real-world problems fuels investments into relevant organizations. Although academic institutions favor exponential speedups, enterprises value any edge over competitors, including quadratic and quartic speedups.
Although the term “quantum advantage” was initially applied to speed, other potential advantages have been discovered. As noted on our “Quantum Computer Technology: Architecture, Advantages and Disadvantages” page, these other advantages include:
Other advantages have been cited that result from quantum computing being primarily cloud services. Although these advantages apply to other cloud services, as well, they can be thought of as advantages over on-premises high performance computing (HPC) resources. As noted on our “Quantum-as-a-Service: Definition, Advantages and Examples” page, these advantages include:
Furthermore, quantum computers are generally recognized as consuming less energy than HPC resources. This is financially advantageous if the hardware is on-site, and it is the more environmentally-responsible option regardless of location.
In comparing the terms quantum advantage vs quantum supremacy, it must be noted that the terms are often used interchangeably. In regard to their most common uses, however, there are distinctions in their definitions:
The key differences between these definitions, therefore, are:
In summary, “Supremacy” usually has one straightforward meaning, which involves solving problems that supercomputers cannot, whether the problems need to be solved or not. A Techopedia article titled “Quantum Advantage” adds that the parameters of “supremacy” experiments ought to be “reasonable.” Either way, “advantage” is the far more versatile and practical term.
Besides its versatility, Nature correspondence titled “Instead of ‘supremacy’ use ‘quantum advantage’” highlights another reason for the shift in recent years to the increased use of “advantage.” Despite objections, however, the term “supremacy” remains in use for extreme demonstrations of quantum computation.
Quantum advantage in optimization retains the definition of quantum advantage, but applied specifically to solving optimization problems. One reason for this distinction is the classical intractability of many of these problems, all of which have real-world applicability. As these problems scale in size, their complexity can grow much faster.
Hybrid classical-quantum algorithms exist that, like classical algorithms, have scaling problems. The reason for the increased attention, therefore, is the discovery of the applicability of the Rydberg states of neutral atoms to solve certain classically-intractable problems without scaling issues. This is now being looked at as potentially the quickest realization of true quantum advantage.