Quantum computers based on photons may possess key advantages over those based on electrons. To benefit from those advantages, quantum computing startup Xanadu has, for the first time, made a photonic quantum computer publicly available over the cloud.
Whereas classical computers switch transistors either on or off to symbolize data as ones and zeroes, quantum computers use quantum bits or “qubits” that, because of the surreal nature of quantum physics, can be in a state known as superposition where they can act as both 1 and 0. This essentially lets each qubit perform two calculations at once.
If two qubits are quantum-mechanically linked, or entangled, they can help perform 2^2 or four calculations simultaneously; three qubits, 2^3 or eight calculations; and so on. In principle, a quantum computer with 300 qubits could perform more calculations in an instant than there are atoms in the visible universe.