Computer-implemented method for finding an approximate solution for a quadratic unconstrained binary optimization problem, QUBO problem, the method being performed by a computing system and the method comprising: providing, as input to the computing system, the QUBO problem in a form comprising an Ising Hamiltonian operator, iteratively obtaining a cost function, the cost function depending at least on the Ising Hamiltonian operator, one or more spins s i and/or the step of the algorithm within each step of the iteration, obtaining, by the computing system, associated intermediate values of the one or more spins s i using the cost function, obtaining, at the end of the iterative process, by the computing system, final values of the one or more spins s i that approximately minimize the final iteratively obtained cost function, obtaining, by the computing system, from the final values of the one or more spins s i , an approximate solution for the QUBO problem, wherein the step of obtaining updated intermediate values of the one or more spins s i is performed using a gradient descent technique or a sequential updating of intermediate values of the one or more spins.