Quantum annealing-based quantum computers
Quantum annealing is a technique used to find the global minimum or optimal solution to a problem that can have a large number of solutions. Essentially it is used for optimization problems such as the Traveling Salesman Problem (TSP), which seeks to find the shortest path for a traveling salesman to visit every city on the route only once and then return back to their starting city. The TSP sounds very simple in description but is a very hard problem to solve because as the number of cities increase, thousands, millions, or even billions of paths emerge as well, which makes this a combinatorial optimization problem. For this kind of problem, quantum computers are the best because the TSP cannot be solved even by today's fastest computers.
D-Wave, a Canadian company, uses the quantum annealing technology to solve combinatorial optimization problems and their computers have been purchased by Google, Microsoft, and NASA for research...