Has the quantum future already come? Let’s see what is going on.
This article tells us D-Wave began to produce and sell quantum computers in 2011: first, it was a 128-qubit quantum computer, then a 512-qubit one and so on, up to a 2000-qubit quantum computer! Moreover, the main developer of DapCash project Dmitry Gerasimovhas repeatedly received proposals to develop software for D-Wave computers, with which it is possible to hack blockchains and other systems 🙂
Has Quantum Apocalypse already came and we missed it? This is where we need to clarify some things. The quantum computer developed by D-Wave, strictly speaking, can’t be called “quantum” in the truest sense of the word. This so-called adiabatic computer is a classic computer that uses some quantum effects. D-Wave computers can solve only a very narrow range of optimization problems. There is such a problem known, for example, in the economy — cost optimization. You have a lot of parameters, a lot of goals that you need to achieve at the same time. For example, you need to visit a million customers in different places and at the same time, you need to optimize the road, costs, time and so on. This is a classical problem, the so-called “traveling salesman problem”. On conventional computers, it is very difficult to solve — a computer needs to sort out many, many different options, it may take thousands of years, and the D-Wave copes with it in seconds.
But an adiabatic computer is not designed for other tasks, so its use is extremely limited.
In fact, an adiabatic computer is a step in the evolution of a classical computer with a very non-standard architecture that uses some quantum effects. The adiabatic computer doesn’t use the effect of superposition. This is not a “universal” quantum computer that can be used to factorize numbers, to hack encryption systems, etc.
A universal quantum computer is limited to 72 qubits so far – in March 2018, Google reported testing of a laboratory sample of such a computer.