Quantum as a service (QaaS) is the offering of quantum compute facilities as an on demand service.
The compute capacity of quantum computers exceeds conventional CPUs by many millions of instructions per second (MIPS). This increased capacity is owed mostly to the fundamental nature of quantum computers where their qubits allow them to harness quantum superpositions and Entanglement in order to perform many calculations at the same time. This allows quantum computers to be more effective at trying many solutions to a problem and makes them exceptional at breaking encryption.
Companies such as D-Wave, Rigetti, Microsoft and IBM offer their quantum computers for researchers, allowing those who wish to experiment with quantum computing to develop code without the massive resources to design, build and maintain a quantum computer. The inherent complexity of maintaining reliable operation of quantum computers is due to their highly unstable nature as they require super-cooling and other very controlled conditions to achieve quantum states.
In 2018, quantum computing passed its fledgling stages with Rigetti’s development of a 128 qubit supercomputer. Prior, IBM estimated that universal quantum computers would require 100 qubits, a number thought by some to offer compute capacity beyond all the world’s supercomputers.
Lesser qubit computers are generally offered for use as a service for researchers with access through cloud infrastructure. The simpler quantum computers still present the opportunity to see what quantum computing has to offer and develop and understanding of programing for quantum computing.